text: // CodeMirror, copyright (c) by Marijn Haverbeke and others
  // Distributed under an MIT license: http://codemirror.net/LICENSE
  
  // This is CodeMirror (http://codemirror.net), a code editor
  // implemented in JavaScript on top of the browser's DOM.
  //
  // You can find some technical background for some of the code below
  // at http://marijnhaverbeke.nl/blog/#cm-internals .
  
  (function(mod) {
    if (typeof exports == "object" && typeof module == "object") // CommonJS
      module.exports = mod();
    else if (typeof define == "function" && define.amd) // AMD
      return define([], mod);
    else // Plain browser env
      (this || window).CodeMirror = mod();
  })(function() {
    "use strict";
  
    // BROWSER SNIFFING
  
    // Kludges for bugs and behavior differences that can't be feature
    // detected are enabled based on userAgent etc sniffing.
    var userAgent = navigator.userAgent;
    var platform = navigator.platform;
  
    var gecko = /gecko\/\d/i.test(userAgent);
    var ie_upto10 = /MSIE \d/.test(userAgent);
    var ie_11up = /Trident\/(?:[7-9]|\d{2,})\..*rv:(\d+)/.exec(userAgent);
    var ie = ie_upto10 || ie_11up;
    var ie_version = ie && (ie_upto10 ? document.documentMode || 6 : ie_11up[1]);
    var webkit = /WebKit\//.test(userAgent);
    var qtwebkit = webkit && /Qt\/\d+\.\d+/.test(userAgent);
    var chrome = /Chrome\//.test(userAgent);
    var presto = /Opera\//.test(userAgent);
    var safari = /Apple Computer/.test(navigator.vendor);
    var mac_geMountainLion = /Mac OS X 1\d\D([8-9]|\d\d)\D/.test(userAgent);
    var phantom = /PhantomJS/.test(userAgent);
  
    var ios = /AppleWebKit/.test(userAgent) && /Mobile\/\w+/.test(userAgent);
    // This is woefully incomplete. Suggestions for alternative methods welcome.
    var mobile = ios || /Android|webOS|BlackBerry|Opera Mini|Opera Mobi|IEMobile/i.test(userAgent);
    var mac = ios || /Mac/.test(platform);
    var windows = /win/i.test(platform);
  
    var presto_version = presto && userAgent.match(/Version\/(\d*\.\d*)/);
    if (presto_version) presto_version = Number(presto_version[1]);
    if (presto_version && presto_version >= 15) { presto = false; webkit = true; }
    // Some browsers use the wrong event properties to signal cmd/ctrl on OS X
    var flipCtrlCmd = mac && (qtwebkit || presto && (presto_version == null || presto_version < 12.11));
    var captureRightClick = gecko || (ie && ie_version >= 9);
  
    // Optimize some code when these features are not used.
    var sawReadOnlySpans = false, sawCollapsedSpans = false;
  
    // EDITOR CONSTRUCTOR
  
    // A CodeMirror instance represents an editor. This is the object
    // that user code is usually dealing with.
  
    function CodeMirror(place, options) {
      if (!(this instanceof CodeMirror)) return new CodeMirror(place, options);
  
      this.options = options = options ? copyObj(options) : {};
      // Determine effective options based on given values and defaults.
      copyObj(defaults, options, false);
      setGuttersForLineNumbers(options);
  
      var doc = options.value;
      if (typeof doc == "string") doc = new Doc(doc, options.mode, null, options.lineSeparator);
      this.doc = doc;
  
      var input = new CodeMirror.inputStyles[options.inputStyle](this);
      var display = this.display = new Display(place, doc, input);
      display.wrapper.CodeMirror = this;
      updateGutters(this);
      themeChanged(this);
      if (options.lineWrapping)
        this.display.wrapper.className += " CodeMirror-wrap";
      if (options.autofocus && !mobile) display.input.focus();
      initScrollbars(this);
  
      this.state = {
        keyMaps: [],  // stores maps added by addKeyMap
        overlays: [], // highlighting overlays, as added by addOverlay
        modeGen: 0,   // bumped when mode/overlay changes, used to invalidate highlighting info
        overwrite: false,
        delayingBlurEvent: false,
        focused: false,
        suppressEdits: false, // used to disable editing during key handlers when in readOnly mode
        pasteIncoming: false, cutIncoming: false, // help recognize paste/cut edits in input.poll
        selectingText: false,
        draggingText: false,
        highlight: new Delayed(), // stores highlight worker timeout
        keySeq: null,  // Unfinished key sequence
        specialChars: null
      };
  
      var cm = this;
  
      // Override magic textarea content restore that IE sometimes does
      // on our hidden textarea on reload
      if (ie && ie_version < 11) setTimeout(function() { cm.display.input.reset(true); }, 20);
  
      registerEventHandlers(this);
      ensureGlobalHandlers();
  
      startOperation(this);
      this.curOp.forceUpdate = true;
      attachDoc(this, doc);
  
      if ((options.autofocus && !mobile) || cm.hasFocus())
        setTimeout(bind(onFocus, this), 20);
      else
        onBlur(this);
  
      for (var opt in optionHandlers) if (optionHandlers.hasOwnProperty(opt))
        optionHandlers[opt](this, options[opt], Init);
      maybeUpdateLineNumberWidth(this);
      if (options.finishInit) options.finishInit(this);
      for (var i = 0; i < initHooks.length; ++i) initHooks[i](this);
      endOperation(this);
      // Suppress optimizelegibility in Webkit, since it breaks text
      // measuring on line wrapping boundaries.
      if (webkit && options.lineWrapping &&
          getComputedStyle(display.lineDiv).textRendering == "optimizelegibility")
        display.lineDiv.style.textRendering = "auto";
    }
  
    // DISPLAY CONSTRUCTOR
  
    // The display handles the DOM integration, both for input reading
    // and content drawing. It holds references to DOM nodes and
    // display-related state.
  
    function Display(place, doc, input) {
      var d = this;
      this.input = input;
  
      // Covers bottom-right square when both scrollbars are present.
      d.scrollbarFiller = elt("div", null, "CodeMirror-scrollbar-filler");
      d.scrollbarFiller.setAttribute("cm-not-content", "true");
      // Covers bottom of gutter when coverGutterNextToScrollbar is on
      // and h scrollbar is present.
      d.gutterFiller = elt("div", null, "CodeMirror-gutter-filler");
      d.gutterFiller.setAttribute("cm-not-content", "true");
      // Will contain the actual code, positioned to cover the viewport.
      d.lineDiv = elt("div", null, "CodeMirror-code");
      // Elements are added to these to represent selection and cursors.
      d.selectionDiv = elt("div", null, null, "position: relative; z-index: 1");
      d.cursorDiv = elt("div", null, "CodeMirror-cursors");
      // A visibility: hidden element used to find the size of things.
      d.measure = elt("div", null, "CodeMirror-measure");
      // When lines outside of the viewport are measured, they are drawn in this.
      d.lineMeasure = elt("div", null, "CodeMirror-measure");
      // Wraps everything that needs to exist inside the vertically-padded coordinate system
      d.lineSpace = elt("div", [d.measure, d.lineMeasure, d.selectionDiv, d.cursorDiv, d.lineDiv],
                        null, "position: relative; outline: none");
      // Moved around its parent to cover visible view.
      d.mover = elt("div", [elt("div", [d.lineSpace], "CodeMirror-lines")], null, "position: relative");
      // Set to the height of the document, allowing scrolling.
      d.sizer = elt("div", [d.mover], "CodeMirror-sizer");
      d.sizerWidth = null;
      // Behavior of elts with overflow: auto and padding is
      // inconsistent across browsers. This is used to ensure the
      // scrollable area is big enough.
      d.heightForcer = elt("div", null, null, "position: absolute; height: " + scrollerGap + "px; width: 1px;");
      // Will contain the gutters, if any.
      d.gutters = elt("div", null, "CodeMirror-gutters");
      d.lineGutter = null;
      // Actual scrollable element.
      d.scroller = elt("div", [d.sizer, d.heightForcer, d.gutters], "CodeMirror-scroll");
      d.scroller.setAttribute("tabIndex", "-1");
      // The element in which the editor lives.
      d.wrapper = elt("div", [d.scrollbarFiller, d.gutterFiller, d.scroller], "CodeMirror");
  
      // Work around IE7 z-index bug (not perfect, hence IE7 not really being supported)
      if (ie && ie_version < 8) { d.gutters.style.zIndex = -1; d.scroller.style.paddingRight = 0; }
      if (!webkit && !(gecko && mobile)) d.scroller.draggable = true;
  
      if (place) {
        if (place.appendChild) place.appendChild(d.wrapper);
        else place(d.wrapper);
      }
  
      // Current rendered range (may be bigger than the view window).
      d.viewFrom = d.viewTo = doc.first;
      d.reportedViewFrom = d.reportedViewTo = doc.first;
      // Information about the rendered lines.
      d.view = [];
      d.renderedView = null;
      // Holds info about a single rendered line when it was rendered
      // for measurement, while not in view.
      d.externalMeasured = null;
      // Empty space (in pixels) above the view
      d.viewOffset = 0;
      d.lastWrapHeight = d.lastWrapWidth = 0;
      d.updateLineNumbers = null;
  
      d.nativeBarWidth = d.barHeight = d.barWidth = 0;
      d.scrollbarsClipped = false;
  
      // Used to only resize the line number gutter when necessary (when
      // the amount of lines crosses a boundary that makes its width change)
      d.lineNumWidth = d.lineNumInnerWidth = d.lineNumChars = null;
      // Set to true when a non-horizontal-scrolling line widget is
      // added. As an optimization, line widget aligning is skipped when
      // this is false.
      d.alignWidgets = false;
  
      d.cachedCharWidth = d.cachedTextHeight = d.cachedPaddingH = null;
  
      // Tracks the maximum line length so that the horizontal scrollbar
      // can be kept static when scrolling.
      d.maxLine = null;
      d.maxLineLength = 0;
      d.maxLineChanged = false;
  
      // Used for measuring wheel scrolling granularity
      d.wheelDX = d.wheelDY = d.wheelStartX = d.wheelStartY = null;
  
      // True when shift is held down.
      d.shift = false;
  
      // Used to track whether anything happened since the context menu
      // was opened.
      d.selForContextMenu = null;
  
      d.activeTouch = null;
  
      input.init(d);
    }
  
    // STATE UPDATES
  
    // Used to get the editor into a consistent state again when options change.
  
    function loadMode(cm) {
      cm.doc.mode = CodeMirror.getMode(cm.options, cm.doc.modeOption);
      resetModeState(cm);
    }
  
    function resetModeState(cm) {
      cm.doc.iter(function(line) {
        if (line.stateAfter) line.stateAfter = null;
        if (line.styles) line.styles = null;
      });
      cm.doc.frontier = cm.doc.first;
      startWorker(cm, 100);
      cm.state.modeGen++;
      if (cm.curOp) regChange(cm);
    }
  
    function wrappingChanged(cm) {
      if (cm.options.lineWrapping) {
        addClass(cm.display.wrapper, "CodeMirror-wrap");
        cm.display.sizer.style.minWidth = "";
        cm.display.sizerWidth = null;
      } else {
        rmClass(cm.display.wrapper, "CodeMirror-wrap");
        findMaxLine(cm);
      }
      estimateLineHeights(cm);
      regChange(cm);
      clearCaches(cm);
      setTimeout(function(){updateScrollbars(cm);}, 100);
    }
  
    // Returns a function that estimates the height of a line, to use as
    // first approximation until the line becomes visible (and is thus
    // properly measurable).
    function estimateHeight(cm) {
      var th = textHeight(cm.display), wrapping = cm.options.lineWrapping;
      var perLine = wrapping && Math.max(5, cm.display.scroller.clientWidth / charWidth(cm.display) - 3);
      return function(line) {
        if (lineIsHidden(cm.doc, line)) return 0;
  
        var widgetsHeight = 0;
        if (line.widgets) for (var i = 0; i < line.widgets.length; i++) {
          if (line.widgets[i].height) widgetsHeight += line.widgets[i].height;
        }
  
        if (wrapping)
          return widgetsHeight + (Math.ceil(line.text.length / perLine) || 1) * th;
        else
          return widgetsHeight + th;
      };
    }
  
    function estimateLineHeights(cm) {
      var doc = cm.doc, est = estimateHeight(cm);
      doc.iter(function(line) {
        var estHeight = est(line);
        if (estHeight != line.height) updateLineHeight(line, estHeight);
      });
    }
  
    function themeChanged(cm) {
      cm.display.wrapper.className = cm.display.wrapper.className.replace(/\s*cm-s-\S+/g, "") +
        cm.options.theme.replace(/(^|\s)\s*/g, " cm-s-");
      clearCaches(cm);
    }
  
    function guttersChanged(cm) {
      updateGutters(cm);
      regChange(cm);
      setTimeout(function(){alignHorizontally(cm);}, 20);
    }
  
    // Rebuild the gutter elements, ensure the margin to the left of the
    // code matches their width.
    function updateGutters(cm) {
      var gutters = cm.display.gutters, specs = cm.options.gutters;
      removeChildren(gutters);
      for (var i = 0; i < specs.length; ++i) {
        var gutterClass = specs[i];
        var gElt = gutters.appendChild(elt("div", null, "CodeMirror-gutter " + gutterClass));
        if (gutterClass == "CodeMirror-linenumbers") {
          cm.display.lineGutter = gElt;
          gElt.style.width = (cm.display.lineNumWidth || 1) + "px";
        }
      }
      gutters.style.display = i ? "" : "none";
      updateGutterSpace(cm);
    }
  
    function updateGutterSpace(cm) {
      var width = cm.display.gutters.offsetWidth;
      cm.display.sizer.style.marginLeft = width + "px";
    }
  
    // Compute the character length of a line, taking into account
    // collapsed ranges (see markText) that might hide parts, and join
    // other lines onto it.
    function lineLength(line) {
      if (line.height == 0) return 0;
      var len = line.text.length, merged, cur = line;
      while (merged = collapsedSpanAtStart(cur)) {
        var found = merged.find(0, true);
        cur = found.from.line;
        len += found.from.ch - found.to.ch;
      }
      cur = line;
      while (merged = collapsedSpanAtEnd(cur)) {
        var found = merged.find(0, true);
        len -= cur.text.length - found.from.ch;
        cur = found.to.line;
        len += cur.text.length - found.to.ch;
      }
      return len;
    }
  
    // Find the longest line in the document.
    function findMaxLine(cm) {
      var d = cm.display, doc = cm.doc;
      d.maxLine = getLine(doc, doc.first);
      d.maxLineLength = lineLength(d.maxLine);
      d.maxLineChanged = true;
      doc.iter(function(line) {
        var len = lineLength(line);
        if (len > d.maxLineLength) {
          d.maxLineLength = len;
          d.maxLine = line;
        }
      });
    }
  
    // Make sure the gutters options contains the element
    // "CodeMirror-linenumbers" when the lineNumbers option is true.
    function setGuttersForLineNumbers(options) {
      var found = indexOf(options.gutters, "CodeMirror-linenumbers");
      if (found == -1 && options.lineNumbers) {
        options.gutters = options.gutters.concat(["CodeMirror-linenumbers"]);
      } else if (found > -1 && !options.lineNumbers) {
        options.gutters = options.gutters.slice(0);
        options.gutters.splice(found, 1);
      }
    }
  
    // SCROLLBARS
  
    // Prepare DOM reads needed to update the scrollbars. Done in one
    // shot to minimize update/measure roundtrips.
    function measureForScrollbars(cm) {
      var d = cm.display, gutterW = d.gutters.offsetWidth;
      var docH = Math.round(cm.doc.height + paddingVert(cm.display));
      return {
        clientHeight: d.scroller.clientHeight,
        viewHeight: d.wrapper.clientHeight,
        scrollWidth: d.scroller.scrollWidth, clientWidth: d.scroller.clientWidth,
        viewWidth: d.wrapper.clientWidth,
        barLeft: cm.options.fixedGutter ? gutterW : 0,
        docHeight: docH,
        scrollHeight: docH + scrollGap(cm) + d.barHeight,
        nativeBarWidth: d.nativeBarWidth,
        gutterWidth: gutterW
      };
    }
  
    function NativeScrollbars(place, scroll, cm) {
      this.cm = cm;
      var vert = this.vert = elt("div", [elt("div", null, null, "min-width: 1px")], "CodeMirror-vscrollbar");
      var horiz = this.horiz = elt("div", [elt("div", null, null, "height: 100%; min-height: 1px")], "CodeMirror-hscrollbar");
      place(vert); place(horiz);
  
      on(vert, "scroll", function() {
        if (vert.clientHeight) scroll(vert.scrollTop, "vertical");
      });
      on(horiz, "scroll", function() {
        if (horiz.clientWidth) scroll(horiz.scrollLeft, "horizontal");
      });
  
      this.checkedZeroWidth = false;
      // Need to set a minimum width to see the scrollbar on IE7 (but must not set it on IE8).
      if (ie && ie_version < 8) this.horiz.style.minHeight = this.vert.style.minWidth = "18px";
    }
  
    NativeScrollbars.prototype = copyObj({
      update: function(measure) {
        var needsH = measure.scrollWidth > measure.clientWidth + 1;
        var needsV = measure.scrollHeight > measure.clientHeight + 1;
        var sWidth = measure.nativeBarWidth;
  
        if (needsV) {
          this.vert.style.display = "block";
          this.vert.style.bottom = needsH ? sWidth + "px" : "0";
          var totalHeight = measure.viewHeight - (needsH ? sWidth : 0);
          // A bug in IE8 can cause this value to be negative, so guard it.
          this.vert.firstChild.style.height =
            Math.max(0, measure.scrollHeight - measure.clientHeight + totalHeight) + "px";
        } else {
          this.vert.style.display = "";
          this.vert.firstChild.style.height = "0";
        }
  
        if (needsH) {
          this.horiz.style.display = "block";
          this.horiz.style.right = needsV ? sWidth + "px" : "0";
          this.horiz.style.left = measure.barLeft + "px";
          var totalWidth = measure.viewWidth - measure.barLeft - (needsV ? sWidth : 0);
          this.horiz.firstChild.style.width =
            (measure.scrollWidth - measure.clientWidth + totalWidth) + "px";
        } else {
          this.horiz.style.display = "";
          this.horiz.firstChild.style.width = "0";
        }
  
        if (!this.checkedZeroWidth && measure.clientHeight > 0) {
          if (sWidth == 0) this.zeroWidthHack();
          this.checkedZeroWidth = true;
        }
  
        return {right: needsV ? sWidth : 0, bottom: needsH ? sWidth : 0};
      },
      setScrollLeft: function(pos) {
        if (this.horiz.scrollLeft != pos) this.horiz.scrollLeft = pos;
        if (this.disableHoriz) this.enableZeroWidthBar(this.horiz, this.disableHoriz);
      },
      setScrollTop: function(pos) {
        if (this.vert.scrollTop != pos) this.vert.scrollTop = pos;
        if (this.disableVert) this.enableZeroWidthBar(this.vert, this.disableVert);
      },
      zeroWidthHack: function() {
        var w = mac && !mac_geMountainLion ? "12px" : "18px";
        this.horiz.style.height = this.vert.style.width = w;
        this.horiz.style.pointerEvents = this.vert.style.pointerEvents = "none";
        this.disableHoriz = new Delayed;
        this.disableVert = new Delayed;
      },
      enableZeroWidthBar: function(bar, delay) {
        bar.style.pointerEvents = "auto";
        function maybeDisable() {
          // To find out whether the scrollbar is still visible, we
          // check whether the element under the pixel in the bottom
          // left corner of the scrollbar box is the scrollbar box
          // itself (when the bar is still visible) or its filler child
          // (when the bar is hidden). If it is still visible, we keep
          // it enabled, if it's hidden, we disable pointer events.
          var box = bar.getBoundingClientRect();
          var elt = document.elementFromPoint(box.left + 1, box.bottom - 1);
          if (elt != bar) bar.style.pointerEvents = "none";
          else delay.set(1000, maybeDisable);
        }
        delay.set(1000, maybeDisable);
      },
      clear: function() {
        var parent = this.horiz.parentNode;
        parent.removeChild(this.horiz);
        parent.removeChild(this.vert);
      }
    }, NativeScrollbars.prototype);
  
    function NullScrollbars() {}
  
    NullScrollbars.prototype = copyObj({
      update: function() { return {bottom: 0, right: 0}; },
      setScrollLeft: function() {},
      setScrollTop: function() {},
      clear: function() {}
    }, NullScrollbars.prototype);
  
    CodeMirror.scrollbarModel = {"native": NativeScrollbars, "null": NullScrollbars};
  
    function initScrollbars(cm) {
      if (cm.display.scrollbars) {
        cm.display.scrollbars.clear();
        if (cm.display.scrollbars.addClass)
          rmClass(cm.display.wrapper, cm.display.scrollbars.addClass);
      }
  
      cm.display.scrollbars = new CodeMirror.scrollbarModel[cm.options.scrollbarStyle](function(node) {
        cm.display.wrapper.insertBefore(node, cm.display.scrollbarFiller);
        // Prevent clicks in the scrollbars from killing focus
        on(node, "mousedown", function() {
          if (cm.state.focused) setTimeout(function() { cm.display.input.focus(); }, 0);
        });
        node.setAttribute("cm-not-content", "true");
      }, function(pos, axis) {
        if (axis == "horizontal") setScrollLeft(cm, pos);
        else setScrollTop(cm, pos);
      }, cm);
      if (cm.display.scrollbars.addClass)
        addClass(cm.display.wrapper, cm.display.scrollbars.addClass);
    }
  
    function updateScrollbars(cm, measure) {
      if (!measure) measure = measureForScrollbars(cm);
      var startWidth = cm.display.barWidth, startHeight = cm.display.barHeight;
      updateScrollbarsInner(cm, measure);
      for (var i = 0; i < 4 && startWidth != cm.display.barWidth || startHeight != cm.display.barHeight; i++) {
        if (startWidth != cm.display.barWidth && cm.options.lineWrapping)
          updateHeightsInViewport(cm);
        updateScrollbarsInner(cm, measureForScrollbars(cm));
        startWidth = cm.display.barWidth; startHeight = cm.display.barHeight;
      }
    }
  
    // Re-synchronize the fake scrollbars with the actual size of the
    // content.
    function updateScrollbarsInner(cm, measure) {
      var d = cm.display;
      var sizes = d.scrollbars.update(measure);
  
      d.sizer.style.paddingRight = (d.barWidth = sizes.right) + "px";
      d.sizer.style.paddingBottom = (d.barHeight = sizes.bottom) + "px";
      d.heightForcer.style.borderBottom = sizes.bottom + "px solid transparent"
  
      if (sizes.right && sizes.bottom) {
        d.scrollbarFiller.style.display = "block";
        d.scrollbarFiller.style.height = sizes.bottom + "px";
        d.scrollbarFiller.style.width = sizes.right + "px";
      } else d.scrollbarFiller.style.display = "";
      if (sizes.bottom && cm.options.coverGutterNextToScrollbar && cm.options.fixedGutter) {
        d.gutterFiller.style.display = "block";
        d.gutterFiller.style.height = sizes.bottom + "px";
        d.gutterFiller.style.width = measure.gutterWidth + "px";
      } else d.gutterFiller.style.display = "";
    }
  
    // Compute the lines that are visible in a given viewport (defaults
    // the the current scroll position). viewport may contain top,
    // height, and ensure (see op.scrollToPos) properties.
    function visibleLines(display, doc, viewport) {
      var top = viewport && viewport.top != null ? Math.max(0, viewport.top) : display.scroller.scrollTop;
      top = Math.floor(top - paddingTop(display));
      var bottom = viewport && viewport.bottom != null ? viewport.bottom : top + display.wrapper.clientHeight;
  
      var from = lineAtHeight(doc, top), to = lineAtHeight(doc, bottom);
      // Ensure is a {from: {line, ch}, to: {line, ch}} object, and
      // forces those lines into the viewport (if possible).
      if (viewport && viewport.ensure) {
        var ensureFrom = viewport.ensure.from.line, ensureTo = viewport.ensure.to.line;
        if (ensureFrom < from) {
          from = ensureFrom;
          to = lineAtHeight(doc, heightAtLine(getLine(doc, ensureFrom)) + display.wrapper.clientHeight);
        } else if (Math.min(ensureTo, doc.lastLine()) >= to) {
          from = lineAtHeight(doc, heightAtLine(getLine(doc, ensureTo)) - display.wrapper.clientHeight);
          to = ensureTo;
        }
      }
      return {from: from, to: Math.max(to, from + 1)};
    }
  
    // LINE NUMBERS
  
    // Re-align line numbers and gutter marks to compensate for
    // horizontal scrolling.
    function alignHorizontally(cm) {
      var display = cm.display, view = display.view;
      if (!display.alignWidgets && (!display.gutters.firstChild || !cm.options.fixedGutter)) return;
      var comp = compensateForHScroll(display) - display.scroller.scrollLeft + cm.doc.scrollLeft;
      var gutterW = display.gutters.offsetWidth, left = comp + "px";
      for (var i = 0; i < view.length; i++) if (!view[i].hidden) {
        if (cm.options.fixedGutter && view[i].gutter)
          view[i].gutter.style.left = left;
        var align = view[i].alignable;
        if (align) for (var j = 0; j < align.length; j++)
          align[j].style.left = left;
      }
      if (cm.options.fixedGutter)
        display.gutters.style.left = (comp + gutterW) + "px";
    }
  
    // Used to ensure that the line number gutter is still the right
    // size for the current document size. Returns true when an update
    // is needed.
    function maybeUpdateLineNumberWidth(cm) {
      if (!cm.options.lineNumbers) return false;
      var doc = cm.doc, last = lineNumberFor(cm.options, doc.first + doc.size - 1), display = cm.display;
      if (last.length != display.lineNumChars) {
        var test = display.measure.appendChild(elt("div", [elt("div", last)],
                                                   "CodeMirror-linenumber CodeMirror-gutter-elt"));
        var innerW = test.firstChild.offsetWidth, padding = test.offsetWidth - innerW;
        display.lineGutter.style.width = "";
        display.lineNumInnerWidth = Math.max(innerW, display.lineGutter.offsetWidth - padding) + 1;
        display.lineNumWidth = display.lineNumInnerWidth + padding;
        display.lineNumChars = display.lineNumInnerWidth ? last.length : -1;
        display.lineGutter.style.width = display.lineNumWidth + "px";
        updateGutterSpace(cm);
        return true;
      }
      return false;
    }
  
    function lineNumberFor(options, i) {
      return String(options.lineNumberFormatter(i + options.firstLineNumber));
    }
  
    // Computes display.scroller.scrollLeft + display.gutters.offsetWidth,
    // but using getBoundingClientRect to get a sub-pixel-accurate
    // result.
    function compensateForHScroll(display) {
      return display.scroller.getBoundingClientRect().left - display.sizer.getBoundingClientRect().left;
    }
  
    // DISPLAY DRAWING
  
    function DisplayUpdate(cm, viewport, force) {
      var display = cm.display;
  
      this.viewport = viewport;
      // Store some values that we'll need later (but don't want to force a relayout for)
      this.visible = visibleLines(display, cm.doc, viewport);
      this.editorIsHidden = !display.wrapper.offsetWidth;
      this.wrapperHeight = display.wrapper.clientHeight;
      this.wrapperWidth = display.wrapper.clientWidth;
      this.oldDisplayWidth = displayWidth(cm);
      this.force = force;
      this.dims = getDimensions(cm);
      this.events = [];
    }
  
    DisplayUpdate.prototype.signal = function(emitter, type) {
      if (hasHandler(emitter, type))
        this.events.push(arguments);
    };
    DisplayUpdate.prototype.finish = function() {
      for (var i = 0; i < this.events.length; i++)
        signal.apply(null, this.events[i]);
    };
  
    function maybeClipScrollbars(cm) {
      var display = cm.display;
      if (!display.scrollbarsClipped && display.scroller.offsetWidth) {
        display.nativeBarWidth = display.scroller.offsetWidth - display.scroller.clientWidth;
        display.heightForcer.style.height = scrollGap(cm) + "px";
        display.sizer.style.marginBottom = -display.nativeBarWidth + "px";
        display.sizer.style.borderRightWidth = scrollGap(cm) + "px";
        display.scrollbarsClipped = true;
      }
    }
  
    // Does the actual updating of the line display. Bails out
    // (returning false) when there is nothing to be done and forced is
    // false.
    function updateDisplayIfNeeded(cm, update) {
      var display = cm.display, doc = cm.doc;
  
      if (update.editorIsHidden) {
        resetView(cm);
        return false;
      }
  
      // Bail out if the visible area is already rendered and nothing changed.
      if (!update.force &&
          update.visible.from >= display.viewFrom && update.visible.to <= display.viewTo &&
          (display.updateLineNumbers == null || display.updateLineNumbers >= display.viewTo) &&
          display.renderedView == display.view && countDirtyView(cm) == 0)
        return false;
  
      if (maybeUpdateLineNumberWidth(cm)) {
        resetView(cm);
        update.dims = getDimensions(cm);
      }
  
      // Compute a suitable new viewport (from & to)
      var end = doc.first + doc.size;
      var from = Math.max(update.visible.from - cm.options.viewportMargin, doc.first);
      var to = Math.min(end, update.visible.to + cm.options.viewportMargin);
      if (display.viewFrom < from && from - display.viewFrom < 20) from = Math.max(doc.first, display.viewFrom);
      if (display.viewTo > to && display.viewTo - to < 20) to = Math.min(end, display.viewTo);
      if (sawCollapsedSpans) {
        from = visualLineNo(cm.doc, from);
        to = visualLineEndNo(cm.doc, to);
      }
  
      var different = from != display.viewFrom || to != display.viewTo ||
        display.lastWrapHeight != update.wrapperHeight || display.lastWrapWidth != update.wrapperWidth;
      adjustView(cm, from, to);
  
      display.viewOffset = heightAtLine(getLine(cm.doc, display.viewFrom));
      // Position the mover div to align with the current scroll position
      cm.display.mover.style.top = display.viewOffset + "px";
  
      var toUpdate = countDirtyView(cm);
      if (!different && toUpdate == 0 && !update.force && display.renderedView == display.view &&
          (display.updateLineNumbers == null || display.updateLineNumbers >= display.viewTo))
        return false;
  
      // For big changes, we hide the enclosing element during the
      // update, since that speeds up the operations on most browsers.
      var focused = activeElt();
      if (toUpdate > 4) display.lineDiv.style.display = "none";
      patchDisplay(cm, display.updateLineNumbers, update.dims);
      if (toUpdate > 4) display.lineDiv.style.display = "";
      display.renderedView = display.view;
      // There might have been a widget with a focused element that got
      // hidden or updated, if so re-focus it.
      if (focused && activeElt() != focused && focused.offsetHeight) focused.focus();
  
      // Prevent selection and cursors from interfering with the scroll
      // width and height.
      removeChildren(display.cursorDiv);
      removeChildren(display.selectionDiv);
      display.gutters.style.height = display.sizer.style.minHeight = 0;
  
      if (different) {
        display.lastWrapHeight = update.wrapperHeight;
        display.lastWrapWidth = update.wrapperWidth;
        startWorker(cm, 400);
      }
  
      display.updateLineNumbers = null;
  
      return true;
    }
  
    function postUpdateDisplay(cm, update) {
      var viewport = update.viewport;
  
      for (var first = true;; first = false) {
        if (!first || !cm.options.lineWrapping || update.oldDisplayWidth == displayWidth(cm)) {
          // Clip forced viewport to actual scrollable area.
          if (viewport && viewport.top != null)
            viewport = {top: Math.min(cm.doc.height + paddingVert(cm.display) - displayHeight(cm), viewport.top)};
          // Updated line heights might result in the drawn area not
          // actually covering the viewport. Keep looping until it does.
          update.visible = visibleLines(cm.display, cm.doc, viewport);
          if (update.visible.from >= cm.display.viewFrom && update.visible.to <= cm.display.viewTo)
            break;
        }
        if (!updateDisplayIfNeeded(cm, update)) break;
        updateHeightsInViewport(cm);
        var barMeasure = measureForScrollbars(cm);
        updateSelection(cm);
        updateScrollbars(cm, barMeasure);
        setDocumentHeight(cm, barMeasure);
      }
  
      update.signal(cm, "update", cm);
      if (cm.display.viewFrom != cm.display.reportedViewFrom || cm.display.viewTo != cm.display.reportedViewTo) {
        update.signal(cm, "viewportChange", cm, cm.display.viewFrom, cm.display.viewTo);
        cm.display.reportedViewFrom = cm.display.viewFrom; cm.display.reportedViewTo = cm.display.viewTo;
      }
    }
  
    function updateDisplaySimple(cm, viewport) {
      var update = new DisplayUpdate(cm, viewport);
      if (updateDisplayIfNeeded(cm, update)) {
        updateHeightsInViewport(cm);
        postUpdateDisplay(cm, update);
        var barMeasure = measureForScrollbars(cm);
        updateSelection(cm);
        updateScrollbars(cm, barMeasure);
        setDocumentHeight(cm, barMeasure);
        update.finish();
      }
    }
  
    function setDocumentHeight(cm, measure) {
      cm.display.sizer.style.minHeight = measure.docHeight + "px";
      cm.display.heightForcer.style.top = measure.docHeight + "px";
      cm.display.gutters.style.height = (measure.docHeight + cm.display.barHeight + scrollGap(cm)) + "px";
    }
  
    // Read the actual heights of the rendered lines, and update their
    // stored heights to match.
    function updateHeightsInViewport(cm) {
      var display = cm.display;
      var prevBottom = display.lineDiv.offsetTop;
      for (var i = 0; i < display.view.length; i++) {
        var cur = display.view[i], height;
        if (cur.hidden) continue;
        if (ie && ie_version < 8) {
          var bot = cur.node.offsetTop + cur.node.offsetHeight;
          height = bot - prevBottom;
          prevBottom = bot;
        } else {
          var box = cur.node.getBoundingClientRect();
          height = box.bottom - box.top;
        }
        var diff = cur.line.height - height;
        if (height < 2) height = textHeight(display);
        if (diff > .001 || diff < -.001) {
          updateLineHeight(cur.line, height);
          updateWidgetHeight(cur.line);
          if (cur.rest) for (var j = 0; j < cur.rest.length; j++)
            updateWidgetHeight(cur.rest[j]);
        }
      }
    }
  
    // Read and store the height of line widgets associated with the
    // given line.
    function updateWidgetHeight(line) {
      if (line.widgets) for (var i = 0; i < line.widgets.length; ++i)
        line.widgets[i].height = line.widgets[i].node.parentNode.offsetHeight;
    }
  
    // Do a bulk-read of the DOM positions and sizes needed to draw the
    // view, so that we don't interleave reading and writing to the DOM.
    function getDimensions(cm) {
      var d = cm.display, left = {}, width = {};
      var gutterLeft = d.gutters.clientLeft;
      for (var n = d.gutters.firstChild, i = 0; n; n = n.nextSibling, ++i) {
        left[cm.options.gutters[i]] = n.offsetLeft + n.clientLeft + gutterLeft;
        width[cm.options.gutters[i]] = n.clientWidth;
      }
      return {fixedPos: compensateForHScroll(d),
              gutterTotalWidth: d.gutters.offsetWidth,
              gutterLeft: left,
              gutterWidth: width,
              wrapperWidth: d.wrapper.clientWidth};
    }
  
    // Sync the actual display DOM structure with display.view, removing
    // nodes for lines that are no longer in view, and creating the ones
    // that are not there yet, and updating the ones that are out of
    // date.
    function patchDisplay(cm, updateNumbersFrom, dims) {
      var display = cm.display, lineNumbers = cm.options.lineNumbers;
      var container = display.lineDiv, cur = container.firstChild;
  
      function rm(node) {
        var next = node.nextSibling;
        // Works around a throw-scroll bug in OS X Webkit
        if (webkit && mac && cm.display.currentWheelTarget == node)
          node.style.display = "none";
        else
          node.parentNode.removeChild(node);
        return next;
      }
  
      var view = display.view, lineN = display.viewFrom;
      // Loop over the elements in the view, syncing cur (the DOM nodes
      // in display.lineDiv) with the view as we go.
      for (var i = 0; i < view.length; i++) {
        var lineView = view[i];
        if (lineView.hidden) {
        } else if (!lineView.node || lineView.node.parentNode != container) { // Not drawn yet
          var node = buildLineElement(cm, lineView, lineN, dims);
          container.insertBefore(node, cur);
        } else { // Already drawn
          while (cur != lineView.node) cur = rm(cur);
          var updateNumber = lineNumbers && updateNumbersFrom != null &&
            updateNumbersFrom <= lineN && lineView.lineNumber;
          if (lineView.changes) {
            if (indexOf(lineView.changes, "gutter") > -1) updateNumber = false;
            updateLineForChanges(cm, lineView, lineN, dims);
          }
          if (updateNumber) {
            removeChildren(lineView.lineNumber);
            lineView.lineNumber.appendChild(document.createTextNode(lineNumberFor(cm.options, lineN)));
          }
          cur = lineView.node.nextSibling;
        }
        lineN += lineView.size;
      }
      while (cur) cur = rm(cur);
    }
  
    // When an aspect of a line changes, a string is added to
    // lineView.changes. This updates the relevant part of the line's
    // DOM structure.
    function updateLineForChanges(cm, lineView, lineN, dims) {
      for (var j = 0; j < lineView.changes.length; j++) {
        var type = lineView.changes[j];
        if (type == "text") updateLineText(cm, lineView);
        else if (type == "gutter") updateLineGutter(cm, lineView, lineN, dims);
        else if (type == "class") updateLineClasses(lineView);
        else if (type == "widget") updateLineWidgets(cm, lineView, dims);
      }
      lineView.changes = null;
    }
  
    // Lines with gutter elements, widgets or a background class need to
    // be wrapped, and have the extra elements added to the wrapper div
    function ensureLineWrapped(lineView) {
      if (lineView.node == lineView.text) {
        lineView.node = elt("div", null, null, "position: relative");
        if (lineView.text.parentNode)
          lineView.text.parentNode.replaceChild(lineView.node, lineView.text);
        lineView.node.appendChild(lineView.text);
        if (ie && ie_version < 8) lineView.node.style.zIndex = 2;
      }
      return lineView.node;
    }
  
    function updateLineBackground(lineView) {
      var cls = lineView.bgClass ? lineView.bgClass + " " + (lineView.line.bgClass || "") : lineView.line.bgClass;
      if (cls) cls += " CodeMirror-linebackground";
      if (lineView.background) {
        if (cls) lineView.background.className = cls;
        else { lineView.background.parentNode.removeChild(lineView.background); lineView.background = null; }
      } else if (cls) {
        var wrap = ensureLineWrapped(lineView);
        lineView.background = wrap.insertBefore(elt("div", null, cls), wrap.firstChild);
      }
    }
  
    // Wrapper around buildLineContent which will reuse the structure
    // in display.externalMeasured when possible.
    function getLineContent(cm, lineView) {
      var ext = cm.display.externalMeasured;
      if (ext && ext.line == lineView.line) {
        cm.display.externalMeasured = null;
        lineView.measure = ext.measure;
        return ext.built;
      }
      return buildLineContent(cm, lineView);
    }
  
    // Redraw the line's text. Interacts with the background and text
    // classes because the mode may output tokens that influence these
    // classes.
    function updateLineText(cm, lineView) {
      var cls = lineView.text.className;
      var built = getLineContent(cm, lineView);
      if (lineView.text == lineView.node) lineView.node = built.pre;
      lineView.text.parentNode.replaceChild(built.pre, lineView.text);
      lineView.text = built.pre;
      if (built.bgClass != lineView.bgClass || built.textClass != lineView.textClass) {
        lineView.bgClass = built.bgClass;
        lineView.textClass = built.textClass;
        updateLineClasses(lineView);
      } else if (cls) {
        lineView.text.className = cls;
      }
    }
  
    function updateLineClasses(lineView) {
      updateLineBackground(lineView);
      if (lineView.line.wrapClass)
        ensureLineWrapped(lineView).className = lineView.line.wrapClass;
      else if (lineView.node != lineView.text)
        lineView.node.className = "";
      var textClass = lineView.textClass ? lineView.textClass + " " + (lineView.line.textClass || "") : lineView.line.textClass;
      lineView.text.className = textClass || "";
    }
  
    function updateLineGutter(cm, lineView, lineN, dims) {
      if (lineView.gutter) {
        lineView.node.removeChild(lineView.gutter);
        lineView.gutter = null;
      }
      if (lineView.gutterBackground) {
        lineView.node.removeChild(lineView.gutterBackground);
        lineView.gutterBackground = null;
      }
      if (lineView.line.gutterClass) {
        var wrap = ensureLineWrapped(lineView);
        lineView.gutterBackground = elt("div", null, "CodeMirror-gutter-background " + lineView.line.gutterClass,
                                        "left: " + (cm.options.fixedGutter ? dims.fixedPos : -dims.gutterTotalWidth) +
                                        "px; width: " + dims.gutterTotalWidth + "px");
        wrap.insertBefore(lineView.gutterBackground, lineView.text);
      }
      var markers = lineView.line.gutterMarkers;
      if (cm.options.lineNumbers || markers) {
        var wrap = ensureLineWrapped(lineView);
        var gutterWrap = lineView.gutter = elt("div", null, "CodeMirror-gutter-wrapper", "left: " +
                                               (cm.options.fixedGutter ? dims.fixedPos : -dims.gutterTotalWidth) + "px");
        cm.display.input.setUneditable(gutterWrap);
        wrap.insertBefore(gutterWrap, lineView.text);
        if (lineView.line.gutterClass)
          gutterWrap.className += " " + lineView.line.gutterClass;
        if (cm.options.lineNumbers && (!markers || !markers["CodeMirror-linenumbers"]))
          lineView.lineNumber = gutterWrap.appendChild(
            elt("div", lineNumberFor(cm.options, lineN),
                "CodeMirror-linenumber CodeMirror-gutter-elt",
                "left: " + dims.gutterLeft["CodeMirror-linenumbers"] + "px; width: "
                + cm.display.lineNumInnerWidth + "px"));
        if (markers) for (var k = 0; k < cm.options.gutters.length; ++k) {
          var id = cm.options.gutters[k], found = markers.hasOwnProperty(id) && markers[id];
          if (found)
            gutterWrap.appendChild(elt("div", [found], "CodeMirror-gutter-elt", "left: " +
                                       dims.gutterLeft[id] + "px; width: " + dims.gutterWidth[id] + "px"));
        }
      }
    }
  
    function updateLineWidgets(cm, lineView, dims) {
      if (lineView.alignable) lineView.alignable = null;
      for (var node = lineView.node.firstChild, next; node; node = next) {
        var next = node.nextSibling;
        if (node.className == "CodeMirror-linewidget")
          lineView.node.removeChild(node);
      }
      insertLineWidgets(cm, lineView, dims);
    }
  
    // Build a line's DOM representation from scratch
    function buildLineElement(cm, lineView, lineN, dims) {
      var built = getLineContent(cm, lineView);
      lineView.text = lineView.node = built.pre;
      if (built.bgClass) lineView.bgClass = built.bgClass;
      if (built.textClass) lineView.textClass = built.textClass;
  
      updateLineClasses(lineView);
      updateLineGutter(cm, lineView, lineN, dims);
      insertLineWidgets(cm, lineView, dims);
      return lineView.node;
    }
  
    // A lineView may contain multiple logical lines (when merged by
    // collapsed spans). The widgets for all of them need to be drawn.
    function insertLineWidgets(cm, lineView, dims) {
      insertLineWidgetsFor(cm, lineView.line, lineView, dims, true);
      if (lineView.rest) for (var i = 0; i < lineView.rest.length; i++)
        insertLineWidgetsFor(cm, lineView.rest[i], lineView, dims, false);
    }
  
    function insertLineWidgetsFor(cm, line, lineView, dims, allowAbove) {
      if (!line.widgets) return;
      var wrap = ensureLineWrapped(lineView);
      for (var i = 0, ws = line.widgets; i < ws.length; ++i) {
        var widget = ws[i], node = elt("div", [widget.node], "CodeMirror-linewidget");
        if (!widget.handleMouseEvents) node.setAttribute("cm-ignore-events", "true");
        positionLineWidget(widget, node, lineView, dims);
        cm.display.input.setUneditable(node);
        if (allowAbove && widget.above)
          wrap.insertBefore(node, lineView.gutter || lineView.text);
        else
          wrap.appendChild(node);
        signalLater(widget, "redraw");
      }
    }
  
    function positionLineWidget(widget, node, lineView, dims) {
      if (widget.noHScroll) {
        (lineView.alignable || (lineView.alignable = [])).push(node);
        var width = dims.wrapperWidth;
        node.style.left = dims.fixedPos + "px";
        if (!widget.coverGutter) {
          width -= dims.gutterTotalWidth;
          node.style.paddingLeft = dims.gutterTotalWidth + "px";
        }
        node.style.width = width + "px";
      }
      if (widget.coverGutter) {
        node.style.zIndex = 5;
        node.style.position = "relative";
        if (!widget.noHScroll) node.style.marginLeft = -dims.gutterTotalWidth + "px";
      }
    }
  
    // POSITION OBJECT
  
    // A Pos instance represents a position within the text.
    var Pos = CodeMirror.Pos = function(line, ch) {
      if (!(this instanceof Pos)) return new Pos(line, ch);
      this.line = line; this.ch = ch;
    };
  
    // Compare two positions, return 0 if they are the same, a negative
    // number when a is less, and a positive number otherwise.
    var cmp = CodeMirror.cmpPos = function(a, b) { return a.line - b.line || a.ch - b.ch; };
  
    function copyPos(x) {return Pos(x.line, x.ch);}
    function maxPos(a, b) { return cmp(a, b) < 0 ? b : a; }
    function minPos(a, b) { return cmp(a, b) < 0 ? a : b; }
  
    // INPUT HANDLING
  
    function ensureFocus(cm) {
      if (!cm.state.focused) { cm.display.input.focus(); onFocus(cm); }
    }
  
    // This will be set to an array of strings when copying, so that,
    // when pasting, we know what kind of selections the copied text
    // was made out of.
    var lastCopied = null;
  
    function applyTextInput(cm, inserted, deleted, sel, origin) {
      var doc = cm.doc;
      cm.display.shift = false;
      if (!sel) sel = doc.sel;
  
      var paste = cm.state.pasteIncoming || origin == "paste";
      var textLines = doc.splitLines(inserted), multiPaste = null;
      // When pasing N lines into N selections, insert one line per selection
      if (paste && sel.ranges.length > 1) {
        if (lastCopied && lastCopied.join("\n") == inserted) {
          if (sel.ranges.length % lastCopied.length == 0) {
            multiPaste = [];
            for (var i = 0; i < lastCopied.length; i++)
              multiPaste.push(doc.splitLines(lastCopied[i]));
          }
        } else if (textLines.length == sel.ranges.length) {
          multiPaste = map(textLines, function(l) { return [l]; });
        }
      }
  
      // Normal behavior is to insert the new text into every selection
      for (var i = sel.ranges.length - 1; i >= 0; i--) {
        var range = sel.ranges[i];
        var from = range.from(), to = range.to();
        if (range.empty()) {
          if (deleted && deleted > 0) // Handle deletion
            from = Pos(from.line, from.ch - deleted);
          else if (cm.state.overwrite && !paste) // Handle overwrite
            to = Pos(to.line, Math.min(getLine(doc, to.line).text.length, to.ch + lst(textLines).length));
        }
        var updateInput = cm.curOp.updateInput;
        var changeEvent = {from: from, to: to, text: multiPaste ? multiPaste[i % multiPaste.length] : textLines,
                           origin: origin || (paste ? "paste" : cm.state.cutIncoming ? "cut" : "+input")};
        makeChange(cm.doc, changeEvent);
        signalLater(cm, "inputRead", cm, changeEvent);
      }
      if (inserted && !paste)
        triggerElectric(cm, inserted);
  
      ensureCursorVisible(cm);
      cm.curOp.updateInput = updateInput;
      cm.curOp.typing = true;
      cm.state.pasteIncoming = cm.state.cutIncoming = false;
    }
  
    function handlePaste(e, cm) {
      var pasted = e.clipboardData && e.clipboardData.getData("text/plain");
      if (pasted) {
        e.preventDefault();
        if (!cm.isReadOnly() && !cm.options.disableInput)
          runInOp(cm, function() { applyTextInput(cm, pasted, 0, null, "paste"); });
        return true;
      }
    }
  
    function triggerElectric(cm, inserted) {
      // When an 'electric' character is inserted, immediately trigger a reindent
      if (!cm.options.electricChars || !cm.options.smartIndent) return;
      var sel = cm.doc.sel;
  
      for (var i = sel.ranges.length - 1; i >= 0; i--) {
        var range = sel.ranges[i];
        if (range.head.ch > 100 || (i && sel.ranges[i - 1].head.line == range.head.line)) continue;
        var mode = cm.getModeAt(range.head);
        var indented = false;
        if (mode.electricChars) {
          for (var j = 0; j < mode.electricChars.length; j++)
            if (inserted.indexOf(mode.electricChars.charAt(j)) > -1) {
              indented = indentLine(cm, range.head.line, "smart");
              break;
            }
        } else if (mode.electricInput) {
          if (mode.electricInput.test(getLine(cm.doc, range.head.line).text.slice(0, range.head.ch)))
            indented = indentLine(cm, range.head.line, "smart");
        }
        if (indented) signalLater(cm, "electricInput", cm, range.head.line);
      }
    }
  
    function copyableRanges(cm) {
      var text = [], ranges = [];
      for (var i = 0; i < cm.doc.sel.ranges.length; i++) {
        var line = cm.doc.sel.ranges[i].head.line;
        var lineRange = {anchor: Pos(line, 0), head: Pos(line + 1, 0)};
        ranges.push(lineRange);
        text.push(cm.getRange(lineRange.anchor, lineRange.head));
      }
      return {text: text, ranges: ranges};
    }
  
    function disableBrowserMagic(field) {
      field.setAttribute("autocorrect", "off");
      field.setAttribute("autocapitalize", "off");
      field.setAttribute("spellcheck", "false");
    }
  
    // TEXTAREA INPUT STYLE
  
    function TextareaInput(cm) {
      this.cm = cm;
      // See input.poll and input.reset
      this.prevInput = "";
  
      // Flag that indicates whether we expect input to appear real soon
      // now (after some event like 'keypress' or 'input') and are
      // polling intensively.
      this.pollingFast = false;
      // Self-resetting timeout for the poller
      this.polling = new Delayed();
      // Tracks when input.reset has punted to just putting a short
      // string into the textarea instead of the full selection.
      this.inaccurateSelection = false;
      // Used to work around IE issue with selection being forgotten when focus moves away from textarea
      this.hasSelection = false;
      this.composing = null;
    };
  
    function hiddenTextarea() {
      var te = elt("textarea", null, null, "position: absolute; padding: 0; width: 1px; height: 1em; outline: none");
      var div = elt("div", [te], null, "overflow: hidden; position: relative; width: 3px; height: 0px;");
      // The textarea is kept positioned near the cursor to prevent the
      // fact that it'll be scrolled into view on input from scrolling
      // our fake cursor out of view. On webkit, when wrap=off, paste is
      // very slow. So make the area wide instead.
      if (webkit) te.style.width = "1000px";
      else te.setAttribute("wrap", "off");
      // If border: 0; -- iOS fails to open keyboard (issue #1287)
      if (ios) te.style.border = "1px solid black";
      disableBrowserMagic(te);
      return div;
    }
  
    TextareaInput.prototype = copyObj({
      init: function(display) {
        var input = this, cm = this.cm;
  
        // Wraps and hides input textarea
        var div = this.wrapper = hiddenTextarea();
        // The semihidden textarea that is focused when the editor is
        // focused, and receives input.
        var te = this.textarea = div.firstChild;
        display.wrapper.insertBefore(div, display.wrapper.firstChild);
  
        // Needed to hide big blue blinking cursor on Mobile Safari (doesn't seem to work in iOS 8 anymore)
        if (ios) te.style.width = "0px";
  
        on(te, "input", function() {
          if (ie && ie_version >= 9 && input.hasSelection) input.hasSelection = null;
          input.poll();
        });
  
        on(te, "paste", function(e) {
          if (signalDOMEvent(cm, e) || handlePaste(e, cm)) return
  
          cm.state.pasteIncoming = true;
          input.fastPoll();
        });
  
        function prepareCopyCut(e) {
          if (signalDOMEvent(cm, e)) return
          if (cm.somethingSelected()) {
            lastCopied = cm.getSelections();
            if (input.inaccurateSelection) {
              input.prevInput = "";
              input.inaccurateSelection = false;
              te.value = lastCopied.join("\n");
              selectInput(te);
            }
          } else if (!cm.options.lineWiseCopyCut) {
            return;
          } else {
            var ranges = copyableRanges(cm);
            lastCopied = ranges.text;
            if (e.type == "cut") {
              cm.setSelections(ranges.ranges, null, sel_dontScroll);
            } else {
              input.prevInput = "";
              te.value = ranges.text.join("\n");
              selectInput(te);
            }
          }
          if (e.type == "cut") cm.state.cutIncoming = true;
        }
        on(te, "cut", prepareCopyCut);
        on(te, "copy", prepareCopyCut);
  
        on(display.scroller, "paste", function(e) {
          if (eventInWidget(display, e) || signalDOMEvent(cm, e)) return;
          cm.state.pasteIncoming = true;
          input.focus();
        });
  
        // Prevent normal selection in the editor (we handle our own)
        on(display.lineSpace, "selectstart", function(e) {
          if (!eventInWidget(display, e)) e_preventDefault(e);
        });
  
        on(te, "compositionstart", function() {
          var start = cm.getCursor("from");
          if (input.composing) input.composing.range.clear()
          input.composing = {
            start: start,
            range: cm.markText(start, cm.getCursor("to"), {className: "CodeMirror-composing"})
          };
        });
        on(te, "compositionend", function() {
          if (input.composing) {
            input.poll();
            input.composing.range.clear();
            input.composing = null;
          }
        });
      },
  
      prepareSelection: function() {
        // Redraw the selection and/or cursor
        var cm = this.cm, display = cm.display, doc = cm.doc;
        var result = prepareSelection(cm);
  
        // Move the hidden textarea near the cursor to prevent scrolling artifacts
        if (cm.options.moveInputWithCursor) {
          var headPos = cursorCoords(cm, doc.sel.primary().head, "div");
          var wrapOff = display.wrapper.getBoundingClientRect(), lineOff = display.lineDiv.getBoundingClientRect();
          result.teTop = Math.max(0, Math.min(display.wrapper.clientHeight - 10,
                                              headPos.top + lineOff.top - wrapOff.top));
          result.teLeft = Math.max(0, Math.min(display.wrapper.clientWidth - 10,
                                               headPos.left + lineOff.left - wrapOff.left));
        }
  
        return result;
      },
  
      showSelection: function(drawn) {
        var cm = this.cm, display = cm.display;
        removeChildrenAndAdd(display.cursorDiv, drawn.cursors);
        removeChildrenAndAdd(display.selectionDiv, drawn.selection);
        if (drawn.teTop != null) {
          this.wrapper.style.top = drawn.teTop + "px";
          this.wrapper.style.left = drawn.teLeft + "px";
        }
      },
  
      // Reset the input to correspond to the selection (or to be empty,
      // when not typing and nothing is selected)
      reset: function(typing) {
        if (this.contextMenuPending) return;
        var minimal, selected, cm = this.cm, doc = cm.doc;
        if (cm.somethingSelected()) {
          this.prevInput = "";
          var range = doc.sel.primary();
          minimal = hasCopyEvent &&
            (range.to().line - range.from().line > 100 || (selected = cm.getSelection()).length > 1000);
          var content = minimal ? "-" : selected || cm.getSelection();
          this.textarea.value = content;
          if (cm.state.focused) selectInput(this.textarea);
          if (ie && ie_version >= 9) this.hasSelection = content;
        } else if (!typing) {
          this.prevInput = this.textarea.value = "";
          if (ie && ie_version >= 9) this.hasSelection = null;
        }
        this.inaccurateSelection = minimal;
      },
  
      getField: function() { return this.textarea; },
  
      supportsTouch: function() { return false; },
  
      focus: function() {
        if (this.cm.options.readOnly != "nocursor" && (!mobile || activeElt() != this.textarea)) {
          try { this.textarea.focus(); }
          catch (e) {} // IE8 will throw if the textarea is display: none or not in DOM
        }
      },
  
      blur: function() { this.textarea.blur(); },
  
      resetPosition: function() {
        this.wrapper.style.top = this.wrapper.style.left = 0;
      },
  
      receivedFocus: function() { this.slowPoll(); },
  
      // Poll for input changes, using the normal rate of polling. This
      // runs as long as the editor is focused.
      slowPoll: function() {
        var input = this;
        if (input.pollingFast) return;
        input.polling.set(this.cm.options.pollInterval, function() {
          input.poll();
          if (input.cm.state.focused) input.slowPoll();
        });
      },
  
      // When an event has just come in that is likely to add or change
      // something in the input textarea, we poll faster, to ensure that
      // the change appears on the screen quickly.
      fastPoll: function() {
        var missed = false, input = this;
        input.pollingFast = true;
        function p() {
          var changed = input.poll();
          if (!changed && !missed) {missed = true; input.polling.set(60, p);}
          else {input.pollingFast = false; input.slowPoll();}
        }
        input.polling.set(20, p);
      },
  
      // Read input from the textarea, and update the document to match.
      // When something is selected, it is present in the textarea, and
      // selected (unless it is huge, in which case a placeholder is
      // used). When nothing is selected, the cursor sits after previously
      // seen text (can be empty), which is stored in prevInput (we must
      // not reset the textarea when typing, because that breaks IME).
      poll: function() {
        var cm = this.cm, input = this.textarea, prevInput = this.prevInput;
        // Since this is called a *lot*, try to bail out as cheaply as
        // possible when it is clear that nothing happened. hasSelection
        // will be the case when there is a lot of text in the textarea,
        // in which case reading its value would be expensive.
        if (this.contextMenuPending || !cm.state.focused ||
            (hasSelection(input) && !prevInput && !this.composing) ||
            cm.isReadOnly() || cm.options.disableInput || cm.state.keySeq)
          return false;
  
        var text = input.value;
        // If nothing changed, bail.
        if (text == prevInput && !cm.somethingSelected()) return false;
        // Work around nonsensical selection resetting in IE9/10, and
        // inexplicable appearance of private area unicode characters on
        // some key combos in Mac (#2689).
        if (ie && ie_version >= 9 && this.hasSelection === text ||
            mac && /[\uf700-\uf7ff]/.test(text)) {
          cm.display.input.reset();
          return false;
        }
  
        if (cm.doc.sel == cm.display.selForContextMenu) {
          var first = text.charCodeAt(0);
          if (first == 0x200b && !prevInput) prevInput = "\u200b";
          if (first == 0x21da) { this.reset(); return this.cm.execCommand("undo"); }
        }
        // Find the part of the input that is actually new
        var same = 0, l = Math.min(prevInput.length, text.length);
        while (same < l && prevInput.charCodeAt(same) == text.charCodeAt(same)) ++same;
  
        var self = this;
        runInOp(cm, function() {
          applyTextInput(cm, text.slice(same), prevInput.length - same,
                         null, self.composing ? "*compose" : null);
  
          // Don't leave long text in the textarea, since it makes further polling slow
          if (text.length > 1000 || text.indexOf("\n") > -1) input.value = self.prevInput = "";
          else self.prevInput = text;
  
          if (self.composing) {
            self.composing.range.clear();
            self.composing.range = cm.markText(self.composing.start, cm.getCursor("to"),
                                               {className: "CodeMirror-composing"});
          }
        });
        return true;
      },
  
      ensurePolled: function() {
        if (this.pollingFast && this.poll()) this.pollingFast = false;
      },
  
      onKeyPress: function() {
        if (ie && ie_version >= 9) this.hasSelection = null;
        this.fastPoll();
      },
  
      onContextMenu: function(e) {
        var input = this, cm = input.cm, display = cm.display, te = input.textarea;
        var pos = posFromMouse(cm, e), scrollPos = display.scroller.scrollTop;
        if (!pos || presto) return; // Opera is difficult.
  
        // Reset the current text selection only if the click is done outside of the selection
        // and 'resetSelectionOnContextMenu' option is true.
        var reset = cm.options.resetSelectionOnContextMenu;
        if (reset && cm.doc.sel.contains(pos) == -1)
          operation(cm, setSelection)(cm.doc, simpleSelection(pos), sel_dontScroll);
  
        var oldCSS = te.style.cssText, oldWrapperCSS = input.wrapper.style.cssText;
        input.wrapper.style.cssText = "position: absolute"
        var wrapperBox = input.wrapper.getBoundingClientRect()
        te.style.cssText = "position: absolute; width: 30px; height: 30px; top: " + (e.clientY - wrapperBox.top - 5) +
          "px; left: " + (e.clientX - wrapperBox.left - 5) + "px; z-index: 1000; background: " +
          (ie ? "rgba(255, 255, 255, .05)" : "transparent") +
          "; outline: none; border-width: 0; outline: none; overflow: hidden; opacity: .05; filter: alpha(opacity=5);";
        if (webkit) var oldScrollY = window.scrollY; // Work around Chrome issue (#2712)
        display.input.focus();
        if (webkit) window.scrollTo(null, oldScrollY);
        display.input.reset();
        // Adds "Select all" to context menu in FF
        if (!cm.somethingSelected()) te.value = input.prevInput = " ";
        input.contextMenuPending = true;
        display.selForContextMenu = cm.doc.sel;
        clearTimeout(display.detectingSelectAll);
  
        // Select-all will be greyed out if there's nothing to select, so
        // this adds a zero-width space so that we can later check whether
        // it got selected.
        function prepareSelectAllHack() {
          if (te.selectionStart != null) {
            var selected = cm.somethingSelected();
            var extval = "\u200b" + (selected ? te.value : "");
            te.value = "\u21da"; // Used to catch context-menu undo
            te.value = extval;
            input.prevInput = selected ? "" : "\u200b";
            te.selectionStart = 1; te.selectionEnd = extval.length;
            // Re-set this, in case some other handler touched the
            // selection in the meantime.
            display.selForContextMenu = cm.doc.sel;
          }
        }
        function rehide() {
          input.contextMenuPending = false;
          input.wrapper.style.cssText = oldWrapperCSS
          te.style.cssText = oldCSS;
          if (ie && ie_version < 9) display.scrollbars.setScrollTop(display.scroller.scrollTop = scrollPos);
  
          // Try to detect the user choosing select-all
          if (te.selectionStart != null) {
            if (!ie || (ie && ie_version < 9)) prepareSelectAllHack();
            var i = 0, poll = function() {
              if (display.selForContextMenu == cm.doc.sel && te.selectionStart == 0 &&
                  te.selectionEnd > 0 && input.prevInput == "\u200b")
                operation(cm, commands.selectAll)(cm);
              else if (i++ < 10) display.detectingSelectAll = setTimeout(poll, 500);
              else display.input.reset();
            };
            display.detectingSelectAll = setTimeout(poll, 200);
          }
        }
  
        if (ie && ie_version >= 9) prepareSelectAllHack();
        if (captureRightClick) {
          e_stop(e);
          var mouseup = function() {
            off(window, "mouseup", mouseup);
            setTimeout(rehide, 20);
          };
          on(window, "mouseup", mouseup);
        } else {
          setTimeout(rehide, 50);
        }
      },
  
      readOnlyChanged: function(val) {
        if (!val) this.reset();
      },
  
      setUneditable: nothing,
  
      needsContentAttribute: false
    }, TextareaInput.prototype);
  
    // CONTENTEDITABLE INPUT STYLE
  
    function ContentEditableInput(cm) {
      this.cm = cm;
      this.lastAnchorNode = this.lastAnchorOffset = this.lastFocusNode = this.lastFocusOffset = null;
      this.polling = new Delayed();
      this.gracePeriod = false;
    }
  
    ContentEditableInput.prototype = copyObj({
      init: function(display) {
        var input = this, cm = input.cm;
        var div = input.div = display.lineDiv;
        disableBrowserMagic(div);
  
        on(div, "paste", function(e) {
          if (!signalDOMEvent(cm, e)) handlePaste(e, cm);
        })
  
        on(div, "compositionstart", function(e) {
          var data = e.data;
          input.composing = {sel: cm.doc.sel, data: data, startData: data};
          if (!data) return;
          var prim = cm.doc.sel.primary();
          var line = cm.getLine(prim.head.line);
          var found = line.indexOf(data, Math.max(0, prim.head.ch - data.length));
          if (found > -1 && found <= prim.head.ch)
            input.composing.sel = simpleSelection(Pos(prim.head.line, found),
                                                  Pos(prim.head.line, found + data.length));
        });
        on(div, "compositionupdate", function(e) {
          input.composing.data = e.data;
        });
        on(div, "compositionend", function(e) {
          var ours = input.composing;
          if (!ours) return;
          if (e.data != ours.startData && !/\u200b/.test(e.data))
            ours.data = e.data;
          // Need a small delay to prevent other code (input event,
          // selection polling) from doing damage when fired right after
          // compositionend.
          setTimeout(function() {
            if (!ours.handled)
              input.applyComposition(ours);
            if (input.composing == ours)
              input.composing = null;
          }, 50);
        });
  
        on(div, "touchstart", function() {
          input.forceCompositionEnd();
        });
  
        on(div, "input", function() {
          if (input.composing) return;
          if (cm.isReadOnly() || !input.pollContent())
            runInOp(input.cm, function() {regChange(cm);});
        });
  
        function onCopyCut(e) {
          if (signalDOMEvent(cm, e)) return
          if (cm.somethingSelected()) {
            lastCopied = cm.getSelections();
            if (e.type == "cut") cm.replaceSelection("", null, "cut");
          } else if (!cm.options.lineWiseCopyCut) {
            return;
          } else {
            var ranges = copyableRanges(cm);
            lastCopied = ranges.text;
            if (e.type == "cut") {
              cm.operation(function() {
                cm.setSelections(ranges.ranges, 0, sel_dontScroll);
                cm.replaceSelection("", null, "cut");
              });
            }
          }
          // iOS exposes the clipboard API, but seems to discard content inserted into it
          if (e.clipboardData && !ios) {
            e.preventDefault();
            e.clipboardData.clearData();
            e.clipboardData.setData("text/plain", lastCopied.join("\n"));
          } else {
            // Old-fashioned briefly-focus-a-textarea hack
            var kludge = hiddenTextarea(), te = kludge.firstChild;
            cm.display.lineSpace.insertBefore(kludge, cm.display.lineSpace.firstChild);
            te.value = lastCopied.join("\n");
            var hadFocus = document.activeElement;
            selectInput(te);
            setTimeout(function() {
              cm.display.lineSpace.removeChild(kludge);
              hadFocus.focus();
            }, 50);
          }
        }
        on(div, "copy", onCopyCut);
        on(div, "cut", onCopyCut);
      },
  
      prepareSelection: function() {
        var result = prepareSelection(this.cm, false);
        result.focus = this.cm.state.focused;
        return result;
      },
  
      showSelection: function(info) {
        if (!info || !this.cm.display.view.length) return;
        if (info.focus) this.showPrimarySelection();
        this.showMultipleSelections(info);
      },
  
      showPrimarySelection: function() {
        var sel = window.getSelection(), prim = this.cm.doc.sel.primary();
        var curAnchor = domToPos(this.cm, sel.anchorNode, sel.anchorOffset);
        var curFocus = domToPos(this.cm, sel.focusNode, sel.focusOffset);
        if (curAnchor && !curAnchor.bad && curFocus && !curFocus.bad &&
            cmp(minPos(curAnchor, curFocus), prim.from()) == 0 &&
            cmp(maxPos(curAnchor, curFocus), prim.to()) == 0)
          return;
  
        var start = posToDOM(this.cm, prim.from());
        var end = posToDOM(this.cm, prim.to());
        if (!start && !end) return;
  
        var view = this.cm.display.view;
        var old = sel.rangeCount && sel.getRangeAt(0);
        if (!start) {
          start = {node: view[0].measure.map[2], offset: 0};
        } else if (!end) { // FIXME dangerously hacky
          var measure = view[view.length - 1].measure;
          var map = measure.maps ? measure.maps[measure.maps.length - 1] : measure.map;
          end = {node: map[map.length - 1], offset: map[map.length - 2] - map[map.length - 3]};
        }
  
        try { var rng = range(start.node, start.offset, end.offset, end.node); }
        catch(e) {} // Our model of the DOM might be outdated, in which case the range we try to set can be impossible
        if (rng) {
          if (!gecko && this.cm.state.focused) {
            sel.collapse(start.node, start.offset);
            if (!rng.collapsed) sel.addRange(rng);
          } else {
            sel.removeAllRanges();
            sel.addRange(rng);
          }
          if (old && sel.anchorNode == null) sel.addRange(old);
          else if (gecko) this.startGracePeriod();
        }
        this.rememberSelection();
      },
  
      startGracePeriod: function() {
        var input = this;
        clearTimeout(this.gracePeriod);
        this.gracePeriod = setTimeout(function() {
          input.gracePeriod = false;
          if (input.selectionChanged())
            input.cm.operation(function() { input.cm.curOp.selectionChanged = true; });
        }, 20);
      },
  
      showMultipleSelections: function(info) {
        removeChildrenAndAdd(this.cm.display.cursorDiv, info.cursors);
        removeChildrenAndAdd(this.cm.display.selectionDiv, info.selection);
      },
  
      rememberSelection: function() {
        var sel = window.getSelection();
        this.lastAnchorNode = sel.anchorNode; this.lastAnchorOffset = sel.anchorOffset;
        this.lastFocusNode = sel.focusNode; this.lastFocusOffset = sel.focusOffset;
      },
  
      selectionInEditor: function() {
        var sel = window.getSelection();
        if (!sel.rangeCount) return false;
        var node = sel.getRangeAt(0).commonAncestorContainer;
        return contains(this.div, node);
      },
  
      focus: function() {
        if (this.cm.options.readOnly != "nocursor") this.div.focus();
      },
      blur: function() { this.div.blur(); },
      getField: function() { return this.div; },
  
      supportsTouch: function() { return true; },
  
      receivedFocus: function() {
        var input = this;
        if (this.selectionInEditor())
          this.pollSelection();
        else
          runInOp(this.cm, function() { input.cm.curOp.selectionChanged = true; });
  
        function poll() {
          if (input.cm.state.focused) {
            input.pollSelection();
            input.polling.set(input.cm.options.pollInterval, poll);
          }
        }
        this.polling.set(this.cm.options.pollInterval, poll);
      },
  
      selectionChanged: function() {
        var sel = window.getSelection();
        return sel.anchorNode != this.lastAnchorNode || sel.anchorOffset != this.lastAnchorOffset ||
          sel.focusNode != this.lastFocusNode || sel.focusOffset != this.lastFocusOffset;
      },
  
      pollSelection: function() {
        if (!this.composing && !this.gracePeriod && this.selectionChanged()) {
          var sel = window.getSelection(), cm = this.cm;
          this.rememberSelection();
          var anchor = domToPos(cm, sel.anchorNode, sel.anchorOffset);
          var head = domToPos(cm, sel.focusNode, sel.focusOffset);
          if (anchor && head) runInOp(cm, function() {
            setSelection(cm.doc, simpleSelection(anchor, head), sel_dontScroll);
            if (anchor.bad || head.bad) cm.curOp.selectionChanged = true;
          });
        }
      },
  
      pollContent: function() {
        var cm = this.cm, display = cm.display, sel = cm.doc.sel.primary();
        var from = sel.from(), to = sel.to();
        if (from.line < display.viewFrom || to.line > display.viewTo - 1) return false;
  
        var fromIndex;
        if (from.line == display.viewFrom || (fromIndex = findViewIndex(cm, from.line)) == 0) {
          var fromLine = lineNo(display.view[0].line);
          var fromNode = display.view[0].node;
        } else {
          var fromLine = lineNo(display.view[fromIndex].line);
          var fromNode = display.view[fromIndex - 1].node.nextSibling;
        }
        var toIndex = findViewIndex(cm, to.line);
        if (toIndex == display.view.length - 1) {
          var toLine = display.viewTo - 1;
          var toNode = display.lineDiv.lastChild;
        } else {
          var toLine = lineNo(display.view[toIndex + 1].line) - 1;
          var toNode = display.view[toIndex + 1].node.previousSibling;
        }
  
        var newText = cm.doc.splitLines(domTextBetween(cm, fromNode, toNode, fromLine, toLine));
        var oldText = getBetween(cm.doc, Pos(fromLine, 0), Pos(toLine, getLine(cm.doc, toLine).text.length));
        while (newText.length > 1 && oldText.length > 1) {
          if (lst(newText) == lst(oldText)) { newText.pop(); oldText.pop(); toLine--; }
          else if (newText[0] == oldText[0]) { newText.shift(); oldText.shift(); fromLine++; }
          else break;
        }
  
        var cutFront = 0, cutEnd = 0;
        var newTop = newText[0], oldTop = oldText[0], maxCutFront = Math.min(newTop.length, oldTop.length);
        while (cutFront < maxCutFront && newTop.charCodeAt(cutFront) == oldTop.charCodeAt(cutFront))
          ++cutFront;
        var newBot = lst(newText), oldBot = lst(oldText);
        var maxCutEnd = Math.min(newBot.length - (newText.length == 1 ? cutFront : 0),
                                 oldBot.length - (oldText.length == 1 ? cutFront : 0));
        while (cutEnd < maxCutEnd &&
               newBot.charCodeAt(newBot.length - cutEnd - 1) == oldBot.charCodeAt(oldBot.length - cutEnd - 1))
          ++cutEnd;
  
        newText[newText.length - 1] = newBot.slice(0, newBot.length - cutEnd);
        newText[0] = newText[0].slice(cutFront);
  
        var chFrom = Pos(fromLine, cutFront);
        var chTo = Pos(toLine, oldText.length ? lst(oldText).length - cutEnd : 0);
        if (newText.length > 1 || newText[0] || cmp(chFrom, chTo)) {
          replaceRange(cm.doc, newText, chFrom, chTo, "+input");
          return true;
        }
      },
  
      ensurePolled: function() {
        this.forceCompositionEnd();
      },
      reset: function() {
        this.forceCompositionEnd();
      },
      forceCompositionEnd: function() {
        if (!this.composing || this.composing.handled) return;
        this.applyComposition(this.composing);
        this.composing.handled = true;
        this.div.blur();
        this.div.focus();
      },
      applyComposition: function(composing) {
        if (this.cm.isReadOnly())
          operation(this.cm, regChange)(this.cm)
        else if (composing.data && composing.data != composing.startData)
          operation(this.cm, applyTextInput)(this.cm, composing.data, 0, composing.sel);
      },
  
      setUneditable: function(node) {
        node.contentEditable = "false"
      },
  
      onKeyPress: function(e) {
        e.preventDefault();
        if (!this.cm.isReadOnly())
          operation(this.cm, applyTextInput)(this.cm, String.fromCharCode(e.charCode == null ? e.keyCode : e.charCode), 0);
      },
  
      readOnlyChanged: function(val) {
        this.div.contentEditable = String(val != "nocursor")
      },
  
      onContextMenu: nothing,
      resetPosition: nothing,
  
      needsContentAttribute: true
    }, ContentEditableInput.prototype);
  
    function posToDOM(cm, pos) {
      var view = findViewForLine(cm, pos.line);
      if (!view || view.hidden) return null;
      var line = getLine(cm.doc, pos.line);
      var info = mapFromLineView(view, line, pos.line);
  
      var order = getOrder(line), side = "left";
      if (order) {
        var partPos = getBidiPartAt(order, pos.ch);
        side = partPos % 2 ? "right" : "left";
      }
      var result = nodeAndOffsetInLineMap(info.map, pos.ch, side);
      result.offset = result.collapse == "right" ? result.end : result.start;
      return result;
    }
  
    function badPos(pos, bad) { if (bad) pos.bad = true; return pos; }
  
    function domToPos(cm, node, offset) {
      var lineNode;
      if (node == cm.display.lineDiv) {
        lineNode = cm.display.lineDiv.childNodes[offset];
        if (!lineNode) return badPos(cm.clipPos(Pos(cm.display.viewTo - 1)), true);
        node = null; offset = 0;
      } else {
        for (lineNode = node;; lineNode = lineNode.parentNode) {
          if (!lineNode || lineNode == cm.display.lineDiv) return null;
          if (lineNode.parentNode && lineNode.parentNode == cm.display.lineDiv) break;
        }
      }
      for (var i = 0; i < cm.display.view.length; i++) {
        var lineView = cm.display.view[i];
        if (lineView.node == lineNode)
          return locateNodeInLineView(lineView, node, offset);
      }
    }
  
    function locateNodeInLineView(lineView, node, offset) {
      var wrapper = lineView.text.firstChild, bad = false;
      if (!node || !contains(wrapper, node)) return badPos(Pos(lineNo(lineView.line), 0), true);
      if (node == wrapper) {
        bad = true;
        node = wrapper.childNodes[offset];
        offset = 0;
        if (!node) {
          var line = lineView.rest ? lst(lineView.rest) : lineView.line;
          return badPos(Pos(lineNo(line), line.text.length), bad);
        }
      }
  
      var textNode = node.nodeType == 3 ? node : null, topNode = node;
      if (!textNode && node.childNodes.length == 1 && node.firstChild.nodeType == 3) {
        textNode = node.firstChild;
        if (offset) offset = textNode.nodeValue.length;
      }
      while (topNode.parentNode != wrapper) topNode = topNode.parentNode;
      var measure = lineView.measure, maps = measure.maps;
  
      function find(textNode, topNode, offset) {
        for (var i = -1; i < (maps ? maps.length : 0); i++) {
          var map = i < 0 ? measure.map : maps[i];
          for (var j = 0; j < map.length; j += 3) {
            var curNode = map[j + 2];
            if (curNode == textNode || curNode == topNode) {
              var line = lineNo(i < 0 ? lineView.line : lineView.rest[i]);
              var ch = map[j] + offset;
              if (offset < 0 || curNode != textNode) ch = map[j + (offset ? 1 : 0)];
              return Pos(line, ch);
            }
          }
        }
      }
      var found = find(textNode, topNode, offset);
      if (found) return badPos(found, bad);
  
      // FIXME this is all really shaky. might handle the few cases it needs to handle, but likely to cause problems
      for (var after = topNode.nextSibling, dist = textNode ? textNode.nodeValue.length - offset : 0; after; after = after.nextSibling) {
        found = find(after, after.firstChild, 0);
        if (found)
          return badPos(Pos(found.line, found.ch - dist), bad);
        else
          dist += after.textContent.length;
      }
      for (var before = topNode.previousSibling, dist = offset; before; before = before.previousSibling) {
        found = find(before, before.firstChild, -1);
        if (found)
          return badPos(Pos(found.line, found.ch + dist), bad);
        else
          dist += after.textContent.length;
      }
    }
  
    function domTextBetween(cm, from, to, fromLine, toLine) {
      var text = "", closing = false, lineSep = cm.doc.lineSeparator();
      function recognizeMarker(id) { return function(marker) { return marker.id == id; }; }
      function walk(node) {
        if (node.nodeType == 1) {
          var cmText = node.getAttribute("cm-text");
          if (cmText != null) {
            if (cmText == "") cmText = node.textContent.replace(/\u200b/g, "");
            text += cmText;
            return;
          }
          var markerID = node.getAttribute("cm-marker"), range;
          if (markerID) {
            var found = cm.findMarks(Pos(fromLine, 0), Pos(toLine + 1, 0), recognizeMarker(+markerID));
            if (found.length && (range = found[0].find()))
              text += getBetween(cm.doc, range.from, range.to).join(lineSep);
            return;
          }
          if (node.getAttribute("contenteditable") == "false") return;
          for (var i = 0; i < node.childNodes.length; i++)
            walk(node.childNodes[i]);
          if (/^(pre|div|p)$/i.test(node.nodeName))
            closing = true;
        } else if (node.nodeType == 3) {
          var val = node.nodeValue;
          if (!val) return;
          if (closing) {
            text += lineSep;
            closing = false;
          }
          text += val;
        }
      }
      for (;;) {
        walk(from);
        if (from == to) break;
        from = from.nextSibling;
      }
      return text;
    }
  
    CodeMirror.inputStyles = {"textarea": TextareaInput, "contenteditable": ContentEditableInput};
  
    // SELECTION / CURSOR
  
    // Selection objects are immutable. A new one is created every time
    // the selection changes. A selection is one or more non-overlapping
    // (and non-touching) ranges, sorted, and an integer that indicates
    // which one is the primary selection (the one that's scrolled into
    // view, that getCursor returns, etc).
    function Selection(ranges, primIndex) {
      this.ranges = ranges;
      this.primIndex = primIndex;
    }
  
    Selection.prototype = {
      primary: function() { return this.ranges[this.primIndex]; },
      equals: function(other) {
        if (other == this) return true;
        if (other.primIndex != this.primIndex || other.ranges.length != this.ranges.length) return false;
        for (var i = 0; i < this.ranges.length; i++) {
          var here = this.ranges[i], there = other.ranges[i];
          if (cmp(here.anchor, there.anchor) != 0 || cmp(here.head, there.head) != 0) return false;
        }
        return true;
      },
      deepCopy: function() {
        for (var out = [], i = 0; i < this.ranges.length; i++)
          out[i] = new Range(copyPos(this.ranges[i].anchor), copyPos(this.ranges[i].head));
        return new Selection(out, this.primIndex);
      },
      somethingSelected: function() {
        for (var i = 0; i < this.ranges.length; i++)
          if (!this.ranges[i].empty()) return true;
        return false;
      },
      contains: function(pos, end) {
        if (!end) end = pos;
        for (var i = 0; i < this.ranges.length; i++) {
          var range = this.ranges[i];
          if (cmp(end, range.from()) >= 0 && cmp(pos, range.to()) <= 0)
            return i;
        }
        return -1;
      }
    };
  
    function Range(anchor, head) {
      this.anchor = anchor; this.head = head;
    }
  
    Range.prototype = {
      from: function() { return minPos(this.anchor, this.head); },
      to: function() { return maxPos(this.anchor, this.head); },
      empty: function() {
        return this.head.line == this.anchor.line && this.head.ch == this.anchor.ch;
      }
    };
  
    // Take an unsorted, potentially overlapping set of ranges, and
    // build a selection out of it. 'Consumes' ranges array (modifying
    // it).
    function normalizeSelection(ranges, primIndex) {
      var prim = ranges[primIndex];
      ranges.sort(function(a, b) { return cmp(a.from(), b.from()); });
      primIndex = indexOf(ranges, prim);
      for (var i = 1; i < ranges.length; i++) {
        var cur = ranges[i], prev = ranges[i - 1];
        if (cmp(prev.to(), cur.from()) >= 0) {
          var from = minPos(prev.from(), cur.from()), to = maxPos(prev.to(), cur.to());
          var inv = prev.empty() ? cur.from() == cur.head : prev.from() == prev.head;
          if (i <= primIndex) --primIndex;
          ranges.splice(--i, 2, new Range(inv ? to : from, inv ? from : to));
        }
      }
      return new Selection(ranges, primIndex);
    }
  
    function simpleSelection(anchor, head) {
      return new Selection([new Range(anchor, head || anchor)], 0);
    }
  
    // Most of the external API clips given positions to make sure they
    // actually exist within the document.
    function clipLine(doc, n) {return Math.max(doc.first, Math.min(n, doc.first + doc.size - 1));}
    function clipPos(doc, pos) {
      if (pos.line < doc.first) return Pos(doc.first, 0);
      var last = doc.first + doc.size - 1;
      if (pos.line > last) return Pos(last, getLine(doc, last).text.length);
      return clipToLen(pos, getLine(doc, pos.line).text.length);
    }
    function clipToLen(pos, linelen) {
      var ch = pos.ch;
      if (ch == null || ch > linelen) return Pos(pos.line, linelen);
      else if (ch < 0) return Pos(pos.line, 0);
      else return pos;
    }
    function isLine(doc, l) {return l >= doc.first && l < doc.first + doc.size;}
    function clipPosArray(doc, array) {
      for (var out = [], i = 0; i < array.length; i++) out[i] = clipPos(doc, array[i]);
      return out;
    }
  
    // SELECTION UPDATES
  
    // The 'scroll' parameter given to many of these indicated whether
    // the new cursor position should be scrolled into view after
    // modifying the selection.
  
    // If shift is held or the extend flag is set, extends a range to
    // include a given position (and optionally a second position).
    // Otherwise, simply returns the range between the given positions.
    // Used for cursor motion and such.
    function extendRange(doc, range, head, other) {
      if (doc.cm && doc.cm.display.shift || doc.extend) {
        var anchor = range.anchor;
        if (other) {
          var posBefore = cmp(head, anchor) < 0;
          if (posBefore != (cmp(other, anchor) < 0)) {
            anchor = head;
            head = other;
          } else if (posBefore != (cmp(head, other) < 0)) {
            head = other;
          }
        }
        return new Range(anchor, head);
      } else {
        return new Range(other || head, head);
      }
    }
  
    // Extend the primary selection range, discard the rest.
    function extendSelection(doc, head, other, options) {
      setSelection(doc, new Selection([extendRange(doc, doc.sel.primary(), head, other)], 0), options);
    }
  
    // Extend all selections (pos is an array of selections with length
    // equal the number of selections)
    function extendSelections(doc, heads, options) {
      for (var out = [], i = 0; i < doc.sel.ranges.length; i++)
        out[i] = extendRange(doc, doc.sel.ranges[i], heads[i], null);
      var newSel = normalizeSelection(out, doc.sel.primIndex);
      setSelection(doc, newSel, options);
    }
  
    // Updates a single range in the selection.
    function replaceOneSelection(doc, i, range, options) {
      var ranges = doc.sel.ranges.slice(0);
      ranges[i] = range;
      setSelection(doc, normalizeSelection(ranges, doc.sel.primIndex), options);
    }
  
    // Reset the selection to a single range.
    function setSimpleSelection(doc, anchor, head, options) {
      setSelection(doc, simpleSelection(anchor, head), options);
    }
  
    // Give beforeSelectionChange handlers a change to influence a
    // selection update.
    function filterSelectionChange(doc, sel, options) {
      var obj = {
        ranges: sel.ranges,
        update: function(ranges) {
          this.ranges = [];
          for (var i = 0; i < ranges.length; i++)
            this.ranges[i] = new Range(clipPos(doc, ranges[i].anchor),
                                       clipPos(doc, ranges[i].head));
        },
        origin: options && options.origin
      };
      signal(doc, "beforeSelectionChange", doc, obj);
      if (doc.cm) signal(doc.cm, "beforeSelectionChange", doc.cm, obj);
      if (obj.ranges != sel.ranges) return normalizeSelection(obj.ranges, obj.ranges.length - 1);
      else return sel;
    }
  
    function setSelectionReplaceHistory(doc, sel, options) {
      var done = doc.history.done, last = lst(done);
      if (last && last.ranges) {
        done[done.length - 1] = sel;
        setSelectionNoUndo(doc, sel, options);
      } else {
        setSelection(doc, sel, options);
      }
    }
  
    // Set a new selection.
    function setSelection(doc, sel, options) {
      setSelectionNoUndo(doc, sel, options);
      addSelectionToHistory(doc, doc.sel, doc.cm ? doc.cm.curOp.id : NaN, options);
    }
  
    function setSelectionNoUndo(doc, sel, options) {
      if (hasHandler(doc, "beforeSelectionChange") || doc.cm && hasHandler(doc.cm, "beforeSelectionChange"))
        sel = filterSelectionChange(doc, sel, options);
  
      var bias = options && options.bias ||
        (cmp(sel.primary().head, doc.sel.primary().head) < 0 ? -1 : 1);
      setSelectionInner(doc, skipAtomicInSelection(doc, sel, bias, true));
  
      if (!(options && options.scroll === false) && doc.cm)
        ensureCursorVisible(doc.cm);
    }
  
    function setSelectionInner(doc, sel) {
      if (sel.equals(doc.sel)) return;
  
      doc.sel = sel;
  
      if (doc.cm) {
        doc.cm.curOp.updateInput = doc.cm.curOp.selectionChanged = true;
        signalCursorActivity(doc.cm);
      }
      signalLater(doc, "cursorActivity", doc);
    }
  
    // Verify that the selection does not partially select any atomic
    // marked ranges.
    function reCheckSelection(doc) {
      setSelectionInner(doc, skipAtomicInSelection(doc, doc.sel, null, false), sel_dontScroll);
    }
  
    // Return a selection that does not partially select any atomic
    // ranges.
    function skipAtomicInSelection(doc, sel, bias, mayClear) {
      var out;
      for (var i = 0; i < sel.ranges.length; i++) {
        var range = sel.ranges[i];
        var old = sel.ranges.length == doc.sel.ranges.length && doc.sel.ranges[i];
        var newAnchor = skipAtomic(doc, range.anchor, old && old.anchor, bias, mayClear);
        var newHead = skipAtomic(doc, range.head, old && old.head, bias, mayClear);
        if (out || newAnchor != range.anchor || newHead != range.head) {
          if (!out) out = sel.ranges.slice(0, i);
          out[i] = new Range(newAnchor, newHead);
        }
      }
      return out ? normalizeSelection(out, sel.primIndex) : sel;
    }
  
    function skipAtomicInner(doc, pos, oldPos, dir, mayClear) {
      var line = getLine(doc, pos.line);
      if (line.markedSpans) for (var i = 0; i < line.markedSpans.length; ++i) {
        var sp = line.markedSpans[i], m = sp.marker;
        if ((sp.from == null || (m.inclusiveLeft ? sp.from <= pos.ch : sp.from < pos.ch)) &&
            (sp.to == null || (m.inclusiveRight ? sp.to >= pos.ch : sp.to > pos.ch))) {
          if (mayClear) {
            signal(m, "beforeCursorEnter");
            if (m.explicitlyCleared) {
              if (!line.markedSpans) break;
              else {--i; continue;}
            }
          }
          if (!m.atomic) continue;
  
          if (oldPos) {
            var near = m.find(dir < 0 ? 1 : -1), diff;
            if (dir < 0 ? m.inclusiveRight : m.inclusiveLeft)
              near = movePos(doc, near, -dir, near && near.line == pos.line ? line : null);
            if (near && near.line == pos.line && (diff = cmp(near, oldPos)) && (dir < 0 ? diff < 0 : diff > 0))
              return skipAtomicInner(doc, near, pos, dir, mayClear);
          }
  
          var far = m.find(dir < 0 ? -1 : 1);
          if (dir < 0 ? m.inclusiveLeft : m.inclusiveRight)
            far = movePos(doc, far, dir, far.line == pos.line ? line : null);
          return far ? skipAtomicInner(doc, far, pos, dir, mayClear) : null;
        }
      }
      return pos;
    }
  
    // Ensure a given position is not inside an atomic range.
    function skipAtomic(doc, pos, oldPos, bias, mayClear) {
      var dir = bias || 1;
      var found = skipAtomicInner(doc, pos, oldPos, dir, mayClear) ||
          (!mayClear && skipAtomicInner(doc, pos, oldPos, dir, true)) ||
          skipAtomicInner(doc, pos, oldPos, -dir, mayClear) ||
          (!mayClear && skipAtomicInner(doc, pos, oldPos, -dir, true));
      if (!found) {
        doc.cantEdit = true;
        return Pos(doc.first, 0);
      }
      return found;
    }
  
    function movePos(doc, pos, dir, line) {
      if (dir < 0 && pos.ch == 0) {
        if (pos.line > doc.first) return clipPos(doc, Pos(pos.line - 1));
        else return null;
      } else if (dir > 0 && pos.ch == (line || getLine(doc, pos.line)).text.length) {
        if (pos.line < doc.first + doc.size - 1) return Pos(pos.line + 1, 0);
        else return null;
      } else {
        return new Pos(pos.line, pos.ch + dir);
      }
    }
  
    // SELECTION DRAWING
  
    function updateSelection(cm) {
      cm.display.input.showSelection(cm.display.input.prepareSelection());
    }
  
    function prepareSelection(cm, primary) {
      var doc = cm.doc, result = {};
      var curFragment = result.cursors = document.createDocumentFragment();
      var selFragment = result.selection = document.createDocumentFragment();
  
      for (var i = 0; i < doc.sel.ranges.length; i++) {
        if (primary === false && i == doc.sel.primIndex) continue;
        var range = doc.sel.ranges[i];
        if (range.from().line >= cm.display.viewTo || range.to().line < cm.display.viewFrom) continue;
        var collapsed = range.empty();
        if (collapsed || cm.options.showCursorWhenSelecting)
          drawSelectionCursor(cm, range.head, curFragment);
        if (!collapsed)
          drawSelectionRange(cm, range, selFragment);
      }
      return result;
    }
  
    // Draws a cursor for the given range
    function drawSelectionCursor(cm, head, output) {
      var pos = cursorCoords(cm, head, "div", null, null, !cm.options.singleCursorHeightPerLine);
  
      var cursor = output.appendChild(elt("div", "\u00a0", "CodeMirror-cursor"));
      cursor.style.left = pos.left + "px";
      cursor.style.top = pos.top + "px";
      cursor.style.height = Math.max(0, pos.bottom - pos.top) * cm.options.cursorHeight + "px";
  
      if (pos.other) {
        // Secondary cursor, shown when on a 'jump' in bi-directional text
        var otherCursor = output.appendChild(elt("div", "\u00a0", "CodeMirror-cursor CodeMirror-secondarycursor"));
        otherCursor.style.display = "";
        otherCursor.style.left = pos.other.left + "px";
        otherCursor.style.top = pos.other.top + "px";
        otherCursor.style.height = (pos.other.bottom - pos.other.top) * .85 + "px";
      }
    }
  
    // Draws the given range as a highlighted selection
    function drawSelectionRange(cm, range, output) {
      var display = cm.display, doc = cm.doc;
      var fragment = document.createDocumentFragment();
      var padding = paddingH(cm.display), leftSide = padding.left;
      var rightSide = Math.max(display.sizerWidth, displayWidth(cm) - display.sizer.offsetLeft) - padding.right;
  
      function add(left, top, width, bottom) {
        if (top < 0) top = 0;
        top = Math.round(top);
        bottom = Math.round(bottom);
        fragment.appendChild(elt("div", null, "CodeMirror-selected", "position: absolute; left: " + left +
                                 "px; top: " + top + "px; width: " + (width == null ? rightSide - left : width) +
                                 "px; height: " + (bottom - top) + "px"));
      }
  
      function drawForLine(line, fromArg, toArg) {
        var lineObj = getLine(doc, line);
        var lineLen = lineObj.text.length;
        var start, end;
        function coords(ch, bias) {
          return charCoords(cm, Pos(line, ch), "div", lineObj, bias);
        }
  
        iterateBidiSections(getOrder(lineObj), fromArg || 0, toArg == null ? lineLen : toArg, function(from, to, dir) {
          var leftPos = coords(from, "left"), rightPos, left, right;
          if (from == to) {
            rightPos = leftPos;
            left = right = leftPos.left;
          } else {
            rightPos = coords(to - 1, "right");
            if (dir == "rtl") { var tmp = leftPos; leftPos = rightPos; rightPos = tmp; }
            left = leftPos.left;
            right = rightPos.right;
          }
          if (fromArg == null && from == 0) left = leftSide;
          if (rightPos.top - leftPos.top > 3) { // Different lines, draw top part
            add(left, leftPos.top, null, leftPos.bottom);
            left = leftSide;
            if (leftPos.bottom < rightPos.top) add(left, leftPos.bottom, null, rightPos.top);
          }
          if (toArg == null && to == lineLen) right = rightSide;
          if (!start || leftPos.top < start.top || leftPos.top == start.top && leftPos.left < start.left)
            start = leftPos;
          if (!end || rightPos.bottom > end.bottom || rightPos.bottom == end.bottom && rightPos.right > end.right)
            end = rightPos;
          if (left < leftSide + 1) left = leftSide;
          add(left, rightPos.top, right - left, rightPos.bottom);
        });
        return {start: start, end: end};
      }
  
      var sFrom = range.from(), sTo = range.to();
      if (sFrom.line == sTo.line) {
        drawForLine(sFrom.line, sFrom.ch, sTo.ch);
      } else {
        var fromLine = getLine(doc, sFrom.line), toLine = getLine(doc, sTo.line);
        var singleVLine = visualLine(fromLine) == visualLine(toLine);
        var leftEnd = drawForLine(sFrom.line, sFrom.ch, singleVLine ? fromLine.text.length + 1 : null).end;
        var rightStart = drawForLine(sTo.line, singleVLine ? 0 : null, sTo.ch).start;
        if (singleVLine) {
          if (leftEnd.top < rightStart.top - 2) {
            add(leftEnd.right, leftEnd.top, null, leftEnd.bottom);
            add(leftSide, rightStart.top, rightStart.left, rightStart.bottom);
          } else {
            add(leftEnd.right, leftEnd.top, rightStart.left - leftEnd.right, leftEnd.bottom);
          }
        }
        if (leftEnd.bottom < rightStart.top)
          add(leftSide, leftEnd.bottom, null, rightStart.top);
      }
  
      output.appendChild(fragment);
    }
  
    // Cursor-blinking
    function restartBlink(cm) {
      if (!cm.state.focused) return;
      var display = cm.display;
      clearInterval(display.blinker);
      var on = true;
      display.cursorDiv.style.visibility = "";
      if (cm.options.cursorBlinkRate > 0)
        display.blinker = setInterval(function() {
          display.cursorDiv.style.visibility = (on = !on) ? "" : "hidden";
        }, cm.options.cursorBlinkRate);
      else if (cm.options.cursorBlinkRate < 0)
        display.cursorDiv.style.visibility = "hidden";
    }
  
    // HIGHLIGHT WORKER
  
    function startWorker(cm, time) {
      if (cm.doc.mode.startState && cm.doc.frontier < cm.display.viewTo)
        cm.state.highlight.set(time, bind(highlightWorker, cm));
    }
  
    function highlightWorker(cm) {
      var doc = cm.doc;
      if (doc.frontier < doc.first) doc.frontier = doc.first;
      if (doc.frontier >= cm.display.viewTo) return;
      var end = +new Date + cm.options.workTime;
      var state = copyState(doc.mode, getStateBefore(cm, doc.frontier));
      var changedLines = [];
  
      doc.iter(doc.frontier, Math.min(doc.first + doc.size, cm.display.viewTo + 500), function(line) {
        if (doc.frontier >= cm.display.viewFrom) { // Visible
          var oldStyles = line.styles, tooLong = line.text.length > cm.options.maxHighlightLength;
          var highlighted = highlightLine(cm, line, tooLong ? copyState(doc.mode, state) : state, true);
          line.styles = highlighted.styles;
          var oldCls = line.styleClasses, newCls = highlighted.classes;
          if (newCls) line.styleClasses = newCls;
          else if (oldCls) line.styleClasses = null;
          var ischange = !oldStyles || oldStyles.length != line.styles.length ||
            oldCls != newCls && (!oldCls || !newCls || oldCls.bgClass != newCls.bgClass || oldCls.textClass != newCls.textClass);
          for (var i = 0; !ischange && i < oldStyles.length; ++i) ischange = oldStyles[i] != line.styles[i];
          if (ischange) changedLines.push(doc.frontier);
          line.stateAfter = tooLong ? state : copyState(doc.mode, state);
        } else {
          if (line.text.length <= cm.options.maxHighlightLength)
            processLine(cm, line.text, state);
          line.stateAfter = doc.frontier % 5 == 0 ? copyState(doc.mode, state) : null;
        }
        ++doc.frontier;
        if (+new Date > end) {
          startWorker(cm, cm.options.workDelay);
          return true;
        }
      });
      if (changedLines.length) runInOp(cm, function() {
        for (var i = 0; i < changedLines.length; i++)
          regLineChange(cm, changedLines[i], "text");
      });
    }
  
    // Finds the line to start with when starting a parse. Tries to
    // find a line with a stateAfter, so that it can start with a
    // valid state. If that fails, it returns the line with the
    // smallest indentation, which tends to need the least context to
    // parse correctly.
    function findStartLine(cm, n, precise) {
      var minindent, minline, doc = cm.doc;
      var lim = precise ? -1 : n - (cm.doc.mode.innerMode ? 1000 : 100);
      for (var search = n; search > lim; --search) {
        if (search <= doc.first) return doc.first;
        var line = getLine(doc, search - 1);
        if (line.stateAfter && (!precise || search <= doc.frontier)) return search;
        var indented = countColumn(line.text, null, cm.options.tabSize);
        if (minline == null || minindent > indented) {
          minline = search - 1;
          minindent = indented;
        }
      }
      return minline;
    }
  
    function getStateBefore(cm, n, precise) {
      var doc = cm.doc, display = cm.display;
      if (!doc.mode.startState) return true;
      var pos = findStartLine(cm, n, precise), state = pos > doc.first && getLine(doc, pos-1).stateAfter;
      if (!state) state = startState(doc.mode);
      else state = copyState(doc.mode, state);
      doc.iter(pos, n, function(line) {
        processLine(cm, line.text, state);
        var save = pos == n - 1 || pos % 5 == 0 || pos >= display.viewFrom && pos < display.viewTo;
        line.stateAfter = save ? copyState(doc.mode, state) : null;
        ++pos;
      });
      if (precise) doc.frontier = pos;
      return state;
    }
  
    // POSITION MEASUREMENT
  
    function paddingTop(display) {return display.lineSpace.offsetTop;}
    function paddingVert(display) {return display.mover.offsetHeight - display.lineSpace.offsetHeight;}
    function paddingH(display) {
      if (display.cachedPaddingH) return display.cachedPaddingH;
      var e = removeChildrenAndAdd(display.measure, elt("pre", "x"));
      var style = window.getComputedStyle ? window.getComputedStyle(e) : e.currentStyle;
      var data = {left: parseInt(style.paddingLeft), right: parseInt(style.paddingRight)};
      if (!isNaN(data.left) && !isNaN(data.right)) display.cachedPaddingH = data;
      return data;
    }
  
    function scrollGap(cm) { return scrollerGap - cm.display.nativeBarWidth; }
    function displayWidth(cm) {
      return cm.display.scroller.clientWidth - scrollGap(cm) - cm.display.barWidth;
    }
    function displayHeight(cm) {
      return cm.display.scroller.clientHeight - scrollGap(cm) - cm.display.barHeight;
    }
  
    // Ensure the lineView.wrapping.heights array is populated. This is
    // an array of bottom offsets for the lines that make up a drawn
    // line. When lineWrapping is on, there might be more than one
    // height.
    function ensureLineHeights(cm, lineView, rect) {
      var wrapping = cm.options.lineWrapping;
      var curWidth = wrapping && displayWidth(cm);
      if (!lineView.measure.heights || wrapping && lineView.measure.width != curWidth) {
        var heights = lineView.measure.heights = [];
        if (wrapping) {
          lineView.measure.width = curWidth;
          var rects = lineView.text.firstChild.getClientRects();
          for (var i = 0; i < rects.length - 1; i++) {
            var cur = rects[i], next = rects[i + 1];
            if (Math.abs(cur.bottom - next.bottom) > 2)
              heights.push((cur.bottom + next.top) / 2 - rect.top);
          }
        }
        heights.push(rect.bottom - rect.top);
      }
    }
  
    // Find a line map (mapping character offsets to text nodes) and a
    // measurement cache for the given line number. (A line view might
    // contain multiple lines when collapsed ranges are present.)
    function mapFromLineView(lineView, line, lineN) {
      if (lineView.line == line)
        return {map: lineView.measure.map, cache: lineView.measure.cache};
      for (var i = 0; i < lineView.rest.length; i++)
        if (lineView.rest[i] == line)
          return {map: lineView.measure.maps[i], cache: lineView.measure.caches[i]};
      for (var i = 0; i < lineView.rest.length; i++)
        if (lineNo(lineView.rest[i]) > lineN)
          return {map: lineView.measure.maps[i], cache: lineView.measure.caches[i], before: true};
    }
  
    // Render a line into the hidden node display.externalMeasured. Used
    // when measurement is needed for a line that's not in the viewport.
    function updateExternalMeasurement(cm, line) {
      line = visualLine(line);
      var lineN = lineNo(line);
      var view = cm.display.externalMeasured = new LineView(cm.doc, line, lineN);
      view.lineN = lineN;
      var built = view.built = buildLineContent(cm, view);
      view.text = built.pre;
      removeChildrenAndAdd(cm.display.lineMeasure, built.pre);
      return view;
    }
  
    // Get a {top, bottom, left, right} box (in line-local coordinates)
    // for a given character.
    function measureChar(cm, line, ch, bias) {
      return measureCharPrepared(cm, prepareMeasureForLine(cm, line), ch, bias);
    }
  
    // Find a line view that corresponds to the given line number.
    function findViewForLine(cm, lineN) {
      if (lineN >= cm.display.viewFrom && lineN < cm.display.viewTo)
        return cm.display.view[findViewIndex(cm, lineN)];
      var ext = cm.display.externalMeasured;
      if (ext && lineN >= ext.lineN && lineN < ext.lineN + ext.size)
        return ext;
    }
  
    // Measurement can be split in two steps, the set-up work that
    // applies to the whole line, and the measurement of the actual
    // character. Functions like coordsChar, that need to do a lot of
    // measurements in a row, can thus ensure that the set-up work is
    // only done once.
    function prepareMeasureForLine(cm, line) {
      var lineN = lineNo(line);
      var view = findViewForLine(cm, lineN);
      if (view && !view.text) {
        view = null;
      } else if (view && view.changes) {
        updateLineForChanges(cm, view, lineN, getDimensions(cm));
        cm.curOp.forceUpdate = true;
      }
      if (!view)
        view = updateExternalMeasurement(cm, line);
  
      var info = mapFromLineView(view, line, lineN);
      return {
        line: line, view: view, rect: null,
        map: info.map, cache: info.cache, before: info.before,
        hasHeights: false
      };
    }
  
    // Given a prepared measurement object, measures the position of an
    // actual character (or fetches it from the cache).
    function measureCharPrepared(cm, prepared, ch, bias, varHeight) {
      if (prepared.before) ch = -1;
      var key = ch + (bias || ""), found;
      if (prepared.cache.hasOwnProperty(key)) {
        found = prepared.cache[key];
      } else {
        if (!prepared.rect)
          prepared.rect = prepared.view.text.getBoundingClientRect();
        if (!prepared.hasHeights) {
          ensureLineHeights(cm, prepared.view, prepared.rect);
          prepared.hasHeights = true;
        }
        found = measureCharInner(cm, prepared, ch, bias);
        if (!found.bogus) prepared.cache[key] = found;
      }
      return {left: found.left, right: found.right,
              top: varHeight ? found.rtop : found.top,
              bottom: varHeight ? found.rbottom : found.bottom};
    }
  
    var nullRect = {left: 0, right: 0, top: 0, bottom: 0};
  
    function nodeAndOffsetInLineMap(map, ch, bias) {
      var node, start, end, collapse;
      // First, search the line map for the text node corresponding to,
      // or closest to, the target character.
      for (var i = 0; i < map.length; i += 3) {
        var mStart = map[i], mEnd = map[i + 1];
        if (ch < mStart) {
          start = 0; end = 1;
          collapse = "left";
        } else if (ch < mEnd) {
          start = ch - mStart;
          end = start + 1;
        } else if (i == map.length - 3 || ch == mEnd && map[i + 3] > ch) {
          end = mEnd - mStart;
          start = end - 1;
          if (ch >= mEnd) collapse = "right";
        }
        if (start != null) {
          node = map[i + 2];
          if (mStart == mEnd && bias == (node.insertLeft ? "left" : "right"))
            collapse = bias;
          if (bias == "left" && start == 0)
            while (i && map[i - 2] == map[i - 3] && map[i - 1].insertLeft) {
              node = map[(i -= 3) + 2];
              collapse = "left";
            }
          if (bias == "right" && start == mEnd - mStart)
            while (i < map.length - 3 && map[i + 3] == map[i + 4] && !map[i + 5].insertLeft) {
              node = map[(i += 3) + 2];
              collapse = "right";
            }
          break;
        }
      }
      return {node: node, start: start, end: end, collapse: collapse, coverStart: mStart, coverEnd: mEnd};
    }
  
    function measureCharInner(cm, prepared, ch, bias) {
      var place = nodeAndOffsetInLineMap(prepared.map, ch, bias);
      var node = place.node, start = place.start, end = place.end, collapse = place.collapse;
  
      var rect;
      if (node.nodeType == 3) { // If it is a text node, use a range to retrieve the coordinates.
        for (var i = 0; i < 4; i++) { // Retry a maximum of 4 times when nonsense rectangles are returned
          while (start && isExtendingChar(prepared.line.text.charAt(place.coverStart + start))) --start;
          while (place.coverStart + end < place.coverEnd && isExtendingChar(prepared.line.text.charAt(place.coverStart + end))) ++end;
          if (ie && ie_version < 9 && start == 0 && end == place.coverEnd - place.coverStart) {
            rect = node.parentNode.getBoundingClientRect();
          } else if (ie && cm.options.lineWrapping) {
            var rects = range(node, start, end).getClientRects();
            if (rects.length)
              rect = rects[bias == "right" ? rects.length - 1 : 0];
            else
              rect = nullRect;
          } else {
            rect = range(node, start, end).getBoundingClientRect() || nullRect;
          }
          if (rect.left || rect.right || start == 0) break;
          end = start;
          start = start - 1;
          collapse = "right";
        }
        if (ie && ie_version < 11) rect = maybeUpdateRectForZooming(cm.display.measure, rect);
      } else { // If it is a widget, simply get the box for the whole widget.
        if (start > 0) collapse = bias = "right";
        var rects;
        if (cm.options.lineWrapping && (rects = node.getClientRects()).length > 1)
          rect = rects[bias == "right" ? rects.length - 1 : 0];
        else
          rect = node.getBoundingClientRect();
      }
      if (ie && ie_version < 9 && !start && (!rect || !rect.left && !rect.right)) {
        var rSpan = node.parentNode.getClientRects()[0];
        if (rSpan)
          rect = {left: rSpan.left, right: rSpan.left + charWidth(cm.display), top: rSpan.top, bottom: rSpan.bottom};
        else
          rect = nullRect;
      }
  
      var rtop = rect.top - prepared.rect.top, rbot = rect.bottom - prepared.rect.top;
      var mid = (rtop + rbot) / 2;
      var heights = prepared.view.measure.heights;
      for (var i = 0; i < heights.length - 1; i++)
        if (mid < heights[i]) break;
      var top = i ? heights[i - 1] : 0, bot = heights[i];
      var result = {left: (collapse == "right" ? rect.right : rect.left) - prepared.rect.left,
                    right: (collapse == "left" ? rect.left : rect.right) - prepared.rect.left,
                    top: top, bottom: bot};
      if (!rect.left && !rect.right) result.bogus = true;
      if (!cm.options.singleCursorHeightPerLine) { result.rtop = rtop; result.rbottom = rbot; }
  
      return result;
    }
  
    // Work around problem with bounding client rects on ranges being
    // returned incorrectly when zoomed on IE10 and below.
    function maybeUpdateRectForZooming(measure, rect) {
      if (!window.screen || screen.logicalXDPI == null ||
          screen.logicalXDPI == screen.deviceXDPI || !hasBadZoomedRects(measure))
        return rect;
      var scaleX = screen.logicalXDPI / screen.deviceXDPI;
      var scaleY = screen.logicalYDPI / screen.deviceYDPI;
      return {left: rect.left * scaleX, right: rect.right * scaleX,
              top: rect.top * scaleY, bottom: rect.bottom * scaleY};
    }
  
    function clearLineMeasurementCacheFor(lineView) {
      if (lineView.measure) {
        lineView.measure.cache = {};
        lineView.measure.heights = null;
        if (lineView.rest) for (var i = 0; i < lineView.rest.length; i++)
          lineView.measure.caches[i] = {};
      }
    }
  
    function clearLineMeasurementCache(cm) {
      cm.display.externalMeasure = null;
      removeChildren(cm.display.lineMeasure);
      for (var i = 0; i < cm.display.view.length; i++)
        clearLineMeasurementCacheFor(cm.display.view[i]);
    }
  
    function clearCaches(cm) {
      clearLineMeasurementCache(cm);
      cm.display.cachedCharWidth = cm.display.cachedTextHeight = cm.display.cachedPaddingH = null;
      if (!cm.options.lineWrapping) cm.display.maxLineChanged = true;
      cm.display.lineNumChars = null;
    }
  
    function pageScrollX() { return window.pageXOffset || (document.documentElement || document.body).scrollLeft; }
    function pageScrollY() { return window.pageYOffset || (document.documentElement || document.body).scrollTop; }
  
    // Converts a {top, bottom, left, right} box from line-local
    // coordinates into another coordinate system. Context may be one of
    // "line", "div" (display.lineDiv), "local"/null (editor), "window",
    // or "page".
    function intoCoordSystem(cm, lineObj, rect, context) {
      if (lineObj.widgets) for (var i = 0; i < lineObj.widgets.length; ++i) if (lineObj.widgets[i].above) {
        var size = widgetHeight(lineObj.widgets[i]);
        rect.top += size; rect.bottom += size;
      }
      if (context == "line") return rect;
      if (!context) context = "local";
      var yOff = heightAtLine(lineObj);
      if (context == "local") yOff += paddingTop(cm.display);
      else yOff -= cm.display.viewOffset;
      if (context == "page" || context == "window") {
        var lOff = cm.display.lineSpace.getBoundingClientRect();
        yOff += lOff.top + (context == "window" ? 0 : pageScrollY());
        var xOff = lOff.left + (context == "window" ? 0 : pageScrollX());
        rect.left += xOff; rect.right += xOff;
      }
      rect.top += yOff; rect.bottom += yOff;
      return rect;
    }
  
    // Coverts a box from "div" coords to another coordinate system.
    // Context may be "window", "page", "div", or "local"/null.
    function fromCoordSystem(cm, coords, context) {
      if (context == "div") return coords;
      var left = coords.left, top = coords.top;
      // First move into "page" coordinate system
      if (context == "page") {
        left -= pageScrollX();
        top -= pageScrollY();
      } else if (context == "local" || !context) {
        var localBox = cm.display.sizer.getBoundingClientRect();
        left += localBox.left;
        top += localBox.top;
      }
  
      var lineSpaceBox = cm.display.lineSpace.getBoundingClientRect();
      return {left: left - lineSpaceBox.left, top: top - lineSpaceBox.top};
    }
  
    function charCoords(cm, pos, context, lineObj, bias) {
      if (!lineObj) lineObj = getLine(cm.doc, pos.line);
      return intoCoordSystem(cm, lineObj, measureChar(cm, lineObj, pos.ch, bias), context);
    }
  
    // Returns a box for a given cursor position, which may have an
    // 'other' property containing the position of the secondary cursor
    // on a bidi boundary.
    function cursorCoords(cm, pos, context, lineObj, preparedMeasure, varHeight) {
      lineObj = lineObj || getLine(cm.doc, pos.line);
      if (!preparedMeasure) preparedMeasure = prepareMeasureForLine(cm, lineObj);
      function get(ch, right) {
        var m = measureCharPrepared(cm, preparedMeasure, ch, right ? "right" : "left", varHeight);
        if (right) m.left = m.right; else m.right = m.left;
        return intoCoordSystem(cm, lineObj, m, context);
      }
      function getBidi(ch, partPos) {
        var part = order[partPos], right = part.level % 2;
        if (ch == bidiLeft(part) && partPos && part.level < order[partPos - 1].level) {
          part = order[--partPos];
          ch = bidiRight(part) - (part.level % 2 ? 0 : 1);
          right = true;
        } else if (ch == bidiRight(part) && partPos < order.length - 1 && part.level < order[partPos + 1].level) {
          part = order[++partPos];
          ch = bidiLeft(part) - part.level % 2;
          right = false;
        }
        if (right && ch == part.to && ch > part.from) return get(ch - 1);
        return get(ch, right);
      }
      var order = getOrder(lineObj), ch = pos.ch;
      if (!order) return get(ch);
      var partPos = getBidiPartAt(order, ch);
      var val = getBidi(ch, partPos);
      if (bidiOther != null) val.other = getBidi(ch, bidiOther);
      return val;
    }
  
    // Used to cheaply estimate the coordinates for a position. Used for
    // intermediate scroll updates.
    function estimateCoords(cm, pos) {
      var left = 0, pos = clipPos(cm.doc, pos);
      if (!cm.options.lineWrapping) left = charWidth(cm.display) * pos.ch;
      var lineObj = getLine(cm.doc, pos.line);
      var top = heightAtLine(lineObj) + paddingTop(cm.display);
      return {left: left, right: left, top: top, bottom: top + lineObj.height};
    }
  
    // Positions returned by coordsChar contain some extra information.
    // xRel is the relative x position of the input coordinates compared
    // to the found position (so xRel > 0 means the coordinates are to
    // the right of the character position, for example). When outside
    // is true, that means the coordinates lie outside the line's
    // vertical range.
    function PosWithInfo(line, ch, outside, xRel) {
      var pos = Pos(line, ch);
      pos.xRel = xRel;
      if (outside) pos.outside = true;
      return pos;
    }
  
    // Compute the character position closest to the given coordinates.
    // Input must be lineSpace-local ("div" coordinate system).
    function coordsChar(cm, x, y) {
      var doc = cm.doc;
      y += cm.display.viewOffset;
      if (y < 0) return PosWithInfo(doc.first, 0, true, -1);
      var lineN = lineAtHeight(doc, y), last = doc.first + doc.size - 1;
      if (lineN > last)
        return PosWithInfo(doc.first + doc.size - 1, getLine(doc, last).text.length, true, 1);
      if (x < 0) x = 0;
  
      var lineObj = getLine(doc, lineN);
      for (;;) {
        var found = coordsCharInner(cm, lineObj, lineN, x, y);
        var merged = collapsedSpanAtEnd(lineObj);
        var mergedPos = merged && merged.find(0, true);
        if (merged && (found.ch > mergedPos.from.ch || found.ch == mergedPos.from.ch && found.xRel > 0))
          lineN = lineNo(lineObj = mergedPos.to.line);
        else
          return found;
      }
    }
  
    function coordsCharInner(cm, lineObj, lineNo, x, y) {
      var innerOff = y - heightAtLine(lineObj);
      var wrongLine = false, adjust = 2 * cm.display.wrapper.clientWidth;
      var preparedMeasure = prepareMeasureForLine(cm, lineObj);
  
      function getX(ch) {
        var sp = cursorCoords(cm, Pos(lineNo, ch), "line", lineObj, preparedMeasure);
        wrongLine = true;
        if (innerOff > sp.bottom) return sp.left - adjust;
        else if (innerOff < sp.top) return sp.left + adjust;
        else wrongLine = false;
        return sp.left;
      }
  
      var bidi = getOrder(lineObj), dist = lineObj.text.length;
      var from = lineLeft(lineObj), to = lineRight(lineObj);
      var fromX = getX(from), fromOutside = wrongLine, toX = getX(to), toOutside = wrongLine;
  
      if (x > toX) return PosWithInfo(lineNo, to, toOutside, 1);
      // Do a binary search between these bounds.
      for (;;) {
        if (bidi ? to == from || to == moveVisually(lineObj, from, 1) : to - from <= 1) {
          var ch = x < fromX || x - fromX <= toX - x ? from : to;
          var xDiff = x - (ch == from ? fromX : toX);
          while (isExtendingChar(lineObj.text.charAt(ch))) ++ch;
          var pos = PosWithInfo(lineNo, ch, ch == from ? fromOutside : toOutside,
                                xDiff < -1 ? -1 : xDiff > 1 ? 1 : 0);
          return pos;
        }
        var step = Math.ceil(dist / 2), middle = from + step;
        if (bidi) {
          middle = from;
          for (var i = 0; i < step; ++i) middle = moveVisually(lineObj, middle, 1);
        }
        var middleX = getX(middle);
        if (middleX > x) {to = middle; toX = middleX; if (toOutside = wrongLine) toX += 1000; dist = step;}
        else {from = middle; fromX = middleX; fromOutside = wrongLine; dist -= step;}
      }
    }
  
    var measureText;
    // Compute the default text height.
    function textHeight(display) {
      if (display.cachedTextHeight != null) return display.cachedTextHeight;
      if (measureText == null) {
        measureText = elt("pre");
        // Measure a bunch of lines, for browsers that compute
        // fractional heights.
        for (var i = 0; i < 49; ++i) {
          measureText.appendChild(document.createTextNode("x"));
          measureText.appendChild(elt("br"));
        }
        measureText.appendChild(document.createTextNode("x"));
      }
      removeChildrenAndAdd(display.measure, measureText);
      var height = measureText.offsetHeight / 50;
      if (height > 3) display.cachedTextHeight = height;
      removeChildren(display.measure);
      return height || 1;
    }
  
    // Compute the default character width.
    function charWidth(display) {
      if (display.cachedCharWidth != null) return display.cachedCharWidth;
      var anchor = elt("span", "xxxxxxxxxx");
      var pre = elt("pre", [anchor]);
      removeChildrenAndAdd(display.measure, pre);
      var rect = anchor.getBoundingClientRect(), width = (rect.right - rect.left) / 10;
      if (width > 2) display.cachedCharWidth = width;
      return width || 10;
    }
  
    // OPERATIONS
  
    // Operations are used to wrap a series of changes to the editor
    // state in such a way that each change won't have to update the
    // cursor and display (which would be awkward, slow, and
    // error-prone). Instead, display updates are batched and then all
    // combined and executed at once.
  
    var operationGroup = null;
  
    var nextOpId = 0;
    // Start a new operation.
    function startOperation(cm) {
      cm.curOp = {
        cm: cm,
        viewChanged: false,      // Flag that indicates that lines might need to be redrawn
        startHeight: cm.doc.height, // Used to detect need to update scrollbar
        forceUpdate: false,      // Used to force a redraw
        updateInput: null,       // Whether to reset the input textarea
        typing: false,           // Whether this reset should be careful to leave existing text (for compositing)
        changeObjs: null,        // Accumulated changes, for firing change events
        cursorActivityHandlers: null, // Set of handlers to fire cursorActivity on
        cursorActivityCalled: 0, // Tracks which cursorActivity handlers have been called already
        selectionChanged: false, // Whether the selection needs to be redrawn
        updateMaxLine: false,    // Set when the widest line needs to be determined anew
        scrollLeft: null, scrollTop: null, // Intermediate scroll position, not pushed to DOM yet
        scrollToPos: null,       // Used to scroll to a specific position
        focus: false,
        id: ++nextOpId           // Unique ID
      };
      if (operationGroup) {
        operationGroup.ops.push(cm.curOp);
      } else {
        cm.curOp.ownsGroup = operationGroup = {
          ops: [cm.curOp],
          delayedCallbacks: []
        };
      }
    }
  
    function fireCallbacksForOps(group) {
      // Calls delayed callbacks and cursorActivity handlers until no
      // new ones appear
      var callbacks = group.delayedCallbacks, i = 0;
      do {
        for (; i < callbacks.length; i++)
          callbacks[i].call(null);
        for (var j = 0; j < group.ops.length; j++) {
          var op = group.ops[j];
          if (op.cursorActivityHandlers)
            while (op.cursorActivityCalled < op.cursorActivityHandlers.length)
              op.cursorActivityHandlers[op.cursorActivityCalled++].call(null, op.cm);
        }
      } while (i < callbacks.length);
    }
  
    // Finish an operation, updating the display and signalling delayed events
    function endOperation(cm) {
      var op = cm.curOp, group = op.ownsGroup;
      if (!group) return;
  
      try { fireCallbacksForOps(group); }
      finally {
        operationGroup = null;
        for (var i = 0; i < group.ops.length; i++)
          group.ops[i].cm.curOp = null;
        endOperations(group);
      }
    }
  
    // The DOM updates done when an operation finishes are batched so
    // that the minimum number of relayouts are required.
    function endOperations(group) {
      var ops = group.ops;
      for (var i = 0; i < ops.length; i++) // Read DOM
        endOperation_R1(ops[i]);
      for (var i = 0; i < ops.length; i++) // Write DOM (maybe)
        endOperation_W1(ops[i]);
      for (var i = 0; i < ops.length; i++) // Read DOM
        endOperation_R2(ops[i]);
      for (var i = 0; i < ops.length; i++) // Write DOM (maybe)
        endOperation_W2(ops[i]);
      for (var i = 0; i < ops.length; i++) // Read DOM
        endOperation_finish(ops[i]);
    }
  
    function endOperation_R1(op) {
      var cm = op.cm, display = cm.display;
      maybeClipScrollbars(cm);
      if (op.updateMaxLine) findMaxLine(cm);
  
      op.mustUpdate = op.viewChanged || op.forceUpdate || op.scrollTop != null ||
        op.scrollToPos && (op.scrollToPos.from.line < display.viewFrom ||
                           op.scrollToPos.to.line >= display.viewTo) ||
        display.maxLineChanged && cm.options.lineWrapping;
      op.update = op.mustUpdate &&
        new DisplayUpdate(cm, op.mustUpdate && {top: op.scrollTop, ensure: op.scrollToPos}, op.forceUpdate);
    }
  
    function endOperation_W1(op) {
      op.updatedDisplay = op.mustUpdate && updateDisplayIfNeeded(op.cm, op.update);
    }
  
    function endOperation_R2(op) {
      var cm = op.cm, display = cm.display;
      if (op.updatedDisplay) updateHeightsInViewport(cm);
  
      op.barMeasure = measureForScrollbars(cm);
  
      // If the max line changed since it was last measured, measure it,
      // and ensure the document's width matches it.
      // updateDisplay_W2 will use these properties to do the actual resizing
      if (display.maxLineChanged && !cm.options.lineWrapping) {
        op.adjustWidthTo = measureChar(cm, display.maxLine, display.maxLine.text.length).left + 3;
        cm.display.sizerWidth = op.adjustWidthTo;
        op.barMeasure.scrollWidth =
          Math.max(display.scroller.clientWidth, display.sizer.offsetLeft + op.adjustWidthTo + scrollGap(cm) + cm.display.barWidth);
        op.maxScrollLeft = Math.max(0, display.sizer.offsetLeft + op.adjustWidthTo - displayWidth(cm));
      }
  
      if (op.updatedDisplay || op.selectionChanged)
        op.preparedSelection = display.input.prepareSelection();
    }
  
    function endOperation_W2(op) {
      var cm = op.cm;
  
      if (op.adjustWidthTo != null) {
        cm.display.sizer.style.minWidth = op.adjustWidthTo + "px";
        if (op.maxScrollLeft < cm.doc.scrollLeft)
          setScrollLeft(cm, Math.min(cm.display.scroller.scrollLeft, op.maxScrollLeft), true);
        cm.display.maxLineChanged = false;
      }
  
      if (op.preparedSelection)
        cm.display.input.showSelection(op.preparedSelection);
      if (op.updatedDisplay || op.startHeight != cm.doc.height)
        updateScrollbars(cm, op.barMeasure);
      if (op.updatedDisplay)
        setDocumentHeight(cm, op.barMeasure);
  
      if (op.selectionChanged) restartBlink(cm);
  
      if (cm.state.focused && op.updateInput)
        cm.display.input.reset(op.typing);
      if (op.focus && op.focus == activeElt() && (!document.hasFocus || document.hasFocus()))
        ensureFocus(op.cm);
    }
  
    function endOperation_finish(op) {
      var cm = op.cm, display = cm.display, doc = cm.doc;
  
      if (op.updatedDisplay) postUpdateDisplay(cm, op.update);
  
      // Abort mouse wheel delta measurement, when scrolling explicitly
      if (display.wheelStartX != null && (op.scrollTop != null || op.scrollLeft != null || op.scrollToPos))
        display.wheelStartX = display.wheelStartY = null;
  
      // Propagate the scroll position to the actual DOM scroller
      if (op.scrollTop != null && (display.scroller.scrollTop != op.scrollTop || op.forceScroll)) {
        doc.scrollTop = Math.max(0, Math.min(display.scroller.scrollHeight - display.scroller.clientHeight, op.scrollTop));
        display.scrollbars.setScrollTop(doc.scrollTop);
        display.scroller.scrollTop = doc.scrollTop;
      }
      if (op.scrollLeft != null && (display.scroller.scrollLeft != op.scrollLeft || op.forceScroll)) {
        doc.scrollLeft = Math.max(0, Math.min(display.scroller.scrollWidth - display.scroller.clientWidth, op.scrollLeft));
        display.scrollbars.setScrollLeft(doc.scrollLeft);
        display.scroller.scrollLeft = doc.scrollLeft;
        alignHorizontally(cm);
      }
      // If we need to scroll a specific position into view, do so.
      if (op.scrollToPos) {
        var coords = scrollPosIntoView(cm, clipPos(doc, op.scrollToPos.from),
                                       clipPos(doc, op.scrollToPos.to), op.scrollToPos.margin);
        if (op.scrollToPos.isCursor && cm.state.focused) maybeScrollWindow(cm, coords);
      }
  
      // Fire events for markers that are hidden/unidden by editing or
      // undoing
      var hidden = op.maybeHiddenMarkers, unhidden = op.maybeUnhiddenMarkers;
      if (hidden) for (var i = 0; i < hidden.length; ++i)
        if (!hidden[i].lines.length) signal(hidden[i], "hide");
      if (unhidden) for (var i = 0; i < unhidden.length; ++i)
        if (unhidden[i].lines.length) signal(unhidden[i], "unhide");
  
      if (display.wrapper.offsetHeight)
        doc.scrollTop = cm.display.scroller.scrollTop;
  
      // Fire change events, and delayed event handlers
      if (op.changeObjs)
        signal(cm, "changes", cm, op.changeObjs);
      if (op.update)
        op.update.finish();
    }
  
    // Run the given function in an operation
    function runInOp(cm, f) {
      if (cm.curOp) return f();
      startOperation(cm);
      try { return f(); }
      finally { endOperation(cm); }
    }
    // Wraps a function in an operation. Returns the wrapped function.
    function operation(cm, f) {
      return function() {
        if (cm.curOp) return f.apply(cm, arguments);
        startOperation(cm);
        try { return f.apply(cm, arguments); }
        finally { endOperation(cm); }
      };
    }
    // Used to add methods to editor and doc instances, wrapping them in
    // operations.
    function methodOp(f) {
      return function() {
        if (this.curOp) return f.apply(this, arguments);
        startOperation(this);
        try { return f.apply(this, arguments); }
        finally { endOperation(this); }
      };
    }
    function docMethodOp(f) {
      return function() {
        var cm = this.cm;
        if (!cm || cm.curOp) return f.apply(this, arguments);
        startOperation(cm);
        try { return f.apply(this, arguments); }
        finally { endOperation(cm); }
      };
    }
  
    // VIEW TRACKING
  
    // These objects are used to represent the visible (currently drawn)
    // part of the document. A LineView may correspond to multiple
    // logical lines, if those are connected by collapsed ranges.
    function LineView(doc, line, lineN) {
      // The starting line
      this.line = line;
      // Continuing lines, if any
      this.rest = visualLineContinued(line);
      // Number of logical lines in this visual line
      this.size = this.rest ? lineNo(lst(this.rest)) - lineN + 1 : 1;
      this.node = this.text = null;
      this.hidden = lineIsHidden(doc, line);
    }
  
    // Create a range of LineView objects for the given lines.
    function buildViewArray(cm, from, to) {
      var array = [], nextPos;
      for (var pos = from; pos < to; pos = nextPos) {
        var view = new LineView(cm.doc, getLine(cm.doc, pos), pos);
        nextPos = pos + view.size;
        array.push(view);
      }
      return array;
    }
  
    // Updates the display.view data structure for a given change to the
    // document. From and to are in pre-change coordinates. Lendiff is
    // the amount of lines added or subtracted by the change. This is
    // used for changes that span multiple lines, or change the way
    // lines are divided into visual lines. regLineChange (below)
    // registers single-line changes.
    function regChange(cm, from, to, lendiff) {
      if (from == null) from = cm.doc.first;
      if (to == null) to = cm.doc.first + cm.doc.size;
      if (!lendiff) lendiff = 0;
  
      var display = cm.display;
      if (lendiff && to < display.viewTo &&
          (display.updateLineNumbers == null || display.updateLineNumbers > from))
        display.updateLineNumbers = from;
  
      cm.curOp.viewChanged = true;
  
      if (from >= display.viewTo) { // Change after
        if (sawCollapsedSpans && visualLineNo(cm.doc, from) < display.viewTo)
          resetView(cm);
      } else if (to <= display.viewFrom) { // Change before
        if (sawCollapsedSpans && visualLineEndNo(cm.doc, to + lendiff) > display.viewFrom) {
          resetView(cm);
        } else {
          display.viewFrom += lendiff;
          display.viewTo += lendiff;
        }
      } else if (from <= display.viewFrom && to >= display.viewTo) { // Full overlap
        resetView(cm);
      } else if (from <= display.viewFrom) { // Top overlap
        var cut = viewCuttingPoint(cm, to, to + lendiff, 1);
        if (cut) {
          display.view = display.view.slice(cut.index);
          display.viewFrom = cut.lineN;
          display.viewTo += lendiff;
        } else {
          resetView(cm);
        }
      } else if (to >= display.viewTo) { // Bottom overlap
        var cut = viewCuttingPoint(cm, from, from, -1);
        if (cut) {
          display.view = display.view.slice(0, cut.index);
          display.viewTo = cut.lineN;
        } else {
          resetView(cm);
        }
      } else { // Gap in the middle
        var cutTop = viewCuttingPoint(cm, from, from, -1);
        var cutBot = viewCuttingPoint(cm, to, to + lendiff, 1);
        if (cutTop && cutBot) {
          display.view = display.view.slice(0, cutTop.index)
            .concat(buildViewArray(cm, cutTop.lineN, cutBot.lineN))
            .concat(display.view.slice(cutBot.index));
          display.viewTo += lendiff;
        } else {
          resetView(cm);
        }
      }
  
      var ext = display.externalMeasured;
      if (ext) {
        if (to < ext.lineN)
          ext.lineN += lendiff;
        else if (from < ext.lineN + ext.size)
          display.externalMeasured = null;
      }
    }
  
    // Register a change to a single line. Type must be one of "text",
    // "gutter", "class", "widget"
    function regLineChange(cm, line, type) {
      cm.curOp.viewChanged = true;
      var display = cm.display, ext = cm.display.externalMeasured;
      if (ext && line >= ext.lineN && line < ext.lineN + ext.size)
        display.externalMeasured = null;
  
      if (line < display.viewFrom || line >= display.viewTo) return;
      var lineView = display.view[findViewIndex(cm, line)];
      if (lineView.node == null) return;
      var arr = lineView.changes || (lineView.changes = []);
      if (indexOf(arr, type) == -1) arr.push(type);
    }
  
    // Clear the view.
    function resetView(cm) {
      cm.display.viewFrom = cm.display.viewTo = cm.doc.first;
      cm.display.view = [];
      cm.display.viewOffset = 0;
    }
  
    // Find the view element corresponding to a given line. Return null
    // when the line isn't visible.
    function findViewIndex(cm, n) {
      if (n >= cm.display.viewTo) return null;
      n -= cm.display.viewFrom;
      if (n < 0) return null;
      var view = cm.display.view;
      for (var i = 0; i < view.length; i++) {
        n -= view[i].size;
        if (n < 0) return i;
      }
    }
  
    function viewCuttingPoint(cm, oldN, newN, dir) {
      var index = findViewIndex(cm, oldN), diff, view = cm.display.view;
      if (!sawCollapsedSpans || newN == cm.doc.first + cm.doc.size)
        return {index: index, lineN: newN};
      for (var i = 0, n = cm.display.viewFrom; i < index; i++)
        n += view[i].size;
      if (n != oldN) {
        if (dir > 0) {
          if (index == view.length - 1) return null;
          diff = (n + view[index].size) - oldN;
          index++;
        } else {
          diff = n - oldN;
        }
        oldN += diff; newN += diff;
      }
      while (visualLineNo(cm.doc, newN) != newN) {
        if (index == (dir < 0 ? 0 : view.length - 1)) return null;
        newN += dir * view[index - (dir < 0 ? 1 : 0)].size;
        index += dir;
      }
      return {index: index, lineN: newN};
    }
  
    // Force the view to cover a given range, adding empty view element
    // or clipping off existing ones as needed.
    function adjustView(cm, from, to) {
      var display = cm.display, view = display.view;
      if (view.length == 0 || from >= display.viewTo || to <= display.viewFrom) {
        display.view = buildViewArray(cm, from, to);
        display.viewFrom = from;
      } else {
        if (display.viewFrom > from)
          display.view = buildViewArray(cm, from, display.viewFrom).concat(display.view);
        else if (display.viewFrom < from)
          display.view = display.view.slice(findViewIndex(cm, from));
        display.viewFrom = from;
        if (display.viewTo < to)
          display.view = display.view.concat(buildViewArray(cm, display.viewTo, to));
        else if (display.viewTo > to)
          display.view = display.view.slice(0, findViewIndex(cm, to));
      }
      display.viewTo = to;
    }
  
    // Count the number of lines in the view whose DOM representation is
    // out of date (or nonexistent).
    function countDirtyView(cm) {
      var view = cm.display.view, dirty = 0;
      for (var i = 0; i < view.length; i++) {
        var lineView = view[i];
        if (!lineView.hidden && (!lineView.node || lineView.changes)) ++dirty;
      }
      return dirty;
    }
  
    // EVENT HANDLERS
  
    // Attach the necessary event handlers when initializing the editor
    function registerEventHandlers(cm) {
      var d = cm.display;
      on(d.scroller, "mousedown", operation(cm, onMouseDown));
      // Older IE's will not fire a second mousedown for a double click
      if (ie && ie_version < 11)
        on(d.scroller, "dblclick", operation(cm, function(e) {
          if (signalDOMEvent(cm, e)) return;
          var pos = posFromMouse(cm, e);
          if (!pos || clickInGutter(cm, e) || eventInWidget(cm.display, e)) return;
          e_preventDefault(e);
          var word = cm.findWordAt(pos);
          extendSelection(cm.doc, word.anchor, word.head);
        }));
      else
        on(d.scroller, "dblclick", function(e) { signalDOMEvent(cm, e) || e_preventDefault(e); });
      // Some browsers fire contextmenu *after* opening the menu, at
      // which point we can't mess with it anymore. Context menu is
      // handled in onMouseDown for these browsers.
      if (!captureRightClick) on(d.scroller, "contextmenu", function(e) {onContextMenu(cm, e);});
  
      // Used to suppress mouse event handling when a touch happens
      var touchFinished, prevTouch = {end: 0};
      function finishTouch() {
        if (d.activeTouch) {
          touchFinished = setTimeout(function() {d.activeTouch = null;}, 1000);
          prevTouch = d.activeTouch;
          prevTouch.end = +new Date;
        }
      };
      function isMouseLikeTouchEvent(e) {
        if (e.touches.length != 1) return false;
        var touch = e.touches[0];
        return touch.radiusX <= 1 && touch.radiusY <= 1;
      }
      function farAway(touch, other) {
        if (other.left == null) return true;
        var dx = other.left - touch.left, dy = other.top - touch.top;
        return dx * dx + dy * dy > 20 * 20;
      }
      on(d.scroller, "touchstart", function(e) {
        if (!signalDOMEvent(cm, e) && !isMouseLikeTouchEvent(e)) {
          clearTimeout(touchFinished);
          var now = +new Date;
          d.activeTouch = {start: now, moved: false,
                           prev: now - prevTouch.end <= 300 ? prevTouch : null};
          if (e.touches.length == 1) {
            d.activeTouch.left = e.touches[0].pageX;
            d.activeTouch.top = e.touches[0].pageY;
          }
        }
      });
      on(d.scroller, "touchmove", function() {
        if (d.activeTouch) d.activeTouch.moved = true;
      });
      on(d.scroller, "touchend", function(e) {
        var touch = d.activeTouch;
        if (touch && !eventInWidget(d, e) && touch.left != null &&
            !touch.moved && new Date - touch.start < 300) {
          var pos = cm.coordsChar(d.activeTouch, "page"), range;
          if (!touch.prev || farAway(touch, touch.prev)) // Single tap
            range = new Range(pos, pos);
          else if (!touch.prev.prev || farAway(touch, touch.prev.prev)) // Double tap
            range = cm.findWordAt(pos);
          else // Triple tap
            range = new Range(Pos(pos.line, 0), clipPos(cm.doc, Pos(pos.line + 1, 0)));
          cm.setSelection(range.anchor, range.head);
          cm.focus();
          e_preventDefault(e);
        }
        finishTouch();
      });
      on(d.scroller, "touchcancel", finishTouch);
  
      // Sync scrolling between fake scrollbars and real scrollable
      // area, ensure viewport is updated when scrolling.
      on(d.scroller, "scroll", function() {
        if (d.scroller.clientHeight) {
          setScrollTop(cm, d.scroller.scrollTop);
          setScrollLeft(cm, d.scroller.scrollLeft, true);
          signal(cm, "scroll", cm);
        }
      });
  
      // Listen to wheel events in order to try and update the viewport on time.
      on(d.scroller, "mousewheel", function(e){onScrollWheel(cm, e);});
      on(d.scroller, "DOMMouseScroll", function(e){onScrollWheel(cm, e);});
  
      // Prevent wrapper from ever scrolling
      on(d.wrapper, "scroll", function() { d.wrapper.scrollTop = d.wrapper.scrollLeft = 0; });
  
      d.dragFunctions = {
        enter: function(e) {if (!signalDOMEvent(cm, e)) e_stop(e);},
        over: function(e) {if (!signalDOMEvent(cm, e)) { onDragOver(cm, e); e_stop(e); }},
        start: function(e){onDragStart(cm, e);},
        drop: operation(cm, onDrop),
        leave: function(e) {if (!signalDOMEvent(cm, e)) { clearDragCursor(cm); }}
      };
  
      var inp = d.input.getField();
      on(inp, "keyup", function(e) { onKeyUp.call(cm, e); });
      on(inp, "keydown", operation(cm, onKeyDown));
      on(inp, "keypress", operation(cm, onKeyPress));
      on(inp, "focus", bind(onFocus, cm));
      on(inp, "blur", bind(onBlur, cm));
    }
  
    function dragDropChanged(cm, value, old) {
      var wasOn = old && old != CodeMirror.Init;
      if (!value != !wasOn) {
        var funcs = cm.display.dragFunctions;
        var toggle = value ? on : off;
        toggle(cm.display.scroller, "dragstart", funcs.start);
        toggle(cm.display.scroller, "dragenter", funcs.enter);
        toggle(cm.display.scroller, "dragover", funcs.over);
        toggle(cm.display.scroller, "dragleave", funcs.leave);
        toggle(cm.display.scroller, "drop", funcs.drop);
      }
    }
  
    // Called when the window resizes
    function onResize(cm) {
      var d = cm.display;
      if (d.lastWrapHeight == d.wrapper.clientHeight && d.lastWrapWidth == d.wrapper.clientWidth)
        return;
      // Might be a text scaling operation, clear size caches.
      d.cachedCharWidth = d.cachedTextHeight = d.cachedPaddingH = null;
      d.scrollbarsClipped = false;
      cm.setSize();
    }
  
    // MOUSE EVENTS
  
    // Return true when the given mouse event happened in a widget
    function eventInWidget(display, e) {
      for (var n = e_target(e); n != display.wrapper; n = n.parentNode) {
        if (!n || (n.nodeType == 1 && n.getAttribute("cm-ignore-events") == "true") ||
            (n.parentNode == display.sizer && n != display.mover))
          return true;
      }
    }
  
    // Given a mouse event, find the corresponding position. If liberal
    // is false, it checks whether a gutter or scrollbar was clicked,
    // and returns null if it was. forRect is used by rectangular
    // selections, and tries to estimate a character position even for
    // coordinates beyond the right of the text.
    function posFromMouse(cm, e, liberal, forRect) {
      var display = cm.display;
      if (!liberal && e_target(e).getAttribute("cm-not-content") == "true") return null;
  
      var x, y, space = display.lineSpace.getBoundingClientRect();
      // Fails unpredictably on IE[67] when mouse is dragged around quickly.
      try { x = e.clientX - space.left; y = e.clientY - space.top; }
      catch (e) { return null; }
      var coords = coordsChar(cm, x, y), line;
      if (forRect && coords.xRel == 1 && (line = getLine(cm.doc, coords.line).text).length == coords.ch) {
        var colDiff = countColumn(line, line.length, cm.options.tabSize) - line.length;
        coords = Pos(coords.line, Math.max(0, Math.round((x - paddingH(cm.display).left) / charWidth(cm.display)) - colDiff));
      }
      return coords;
    }
  
    // A mouse down can be a single click, double click, triple click,
    // start of selection drag, start of text drag, new cursor
    // (ctrl-click), rectangle drag (alt-drag), or xwin
    // middle-click-paste. Or it might be a click on something we should
    // not interfere with, such as a scrollbar or widget.
    function onMouseDown(e) {
      var cm = this, display = cm.display;
      if (signalDOMEvent(cm, e) || display.activeTouch && display.input.supportsTouch()) return;
      display.shift = e.shiftKey;
  
      if (eventInWidget(display, e)) {
        if (!webkit) {
          // Briefly turn off draggability, to allow widgets to do
          // normal dragging things.
          display.scroller.draggable = false;
          setTimeout(function(){display.scroller.draggable = true;}, 100);
        }
        return;
      }
      if (clickInGutter(cm, e)) return;
      var start = posFromMouse(cm, e);
      window.focus();
  
      switch (e_button(e)) {
      case 1:
        // #3261: make sure, that we're not starting a second selection
        if (cm.state.selectingText)
          cm.state.selectingText(e);
        else if (start)
          leftButtonDown(cm, e, start);
        else if (e_target(e) == display.scroller)
          e_preventDefault(e);
        break;
      case 2:
        if (webkit) cm.state.lastMiddleDown = +new Date;
        if (start) extendSelection(cm.doc, start);
        setTimeout(function() {display.input.focus();}, 20);
        e_preventDefault(e);
        break;
      case 3:
        if (captureRightClick) onContextMenu(cm, e);
        else delayBlurEvent(cm);
        break;
      }
    }
  
    var lastClick, lastDoubleClick;
    function leftButtonDown(cm, e, start) {
      if (ie) setTimeout(bind(ensureFocus, cm), 0);
      else cm.curOp.focus = activeElt();
  
      var now = +new Date, type;
      if (lastDoubleClick && lastDoubleClick.time > now - 400 && cmp(lastDoubleClick.pos, start) == 0) {
        type = "triple";
      } else if (lastClick && lastClick.time > now - 400 && cmp(lastClick.pos, start) == 0) {
        type = "double";
        lastDoubleClick = {time: now, pos: start};
      } else {
        type = "single";
        lastClick = {time: now, pos: start};
      }
  
      var sel = cm.doc.sel, modifier = mac ? e.metaKey : e.ctrlKey, contained;
      if (cm.options.dragDrop && dragAndDrop && !cm.isReadOnly() &&
          type == "single" && (contained = sel.contains(start)) > -1 &&
          (cmp((contained = sel.ranges[contained]).from(), start) < 0 || start.xRel > 0) &&
          (cmp(contained.to(), start) > 0 || start.xRel < 0))
        leftButtonStartDrag(cm, e, start, modifier);
      else
        leftButtonSelect(cm, e, start, type, modifier);
    }
  
    // Start a text drag. When it ends, see if any dragging actually
    // happen, and treat as a click if it didn't.
    function leftButtonStartDrag(cm, e, start, modifier) {
      var display = cm.display, startTime = +new Date;
      var dragEnd = operation(cm, function(e2) {
        if (webkit) display.scroller.draggable = false;
        cm.state.draggingText = false;
        off(document, "mouseup", dragEnd);
        off(display.scroller, "drop", dragEnd);
        if (Math.abs(e.clientX - e2.clientX) + Math.abs(e.clientY - e2.clientY) < 10) {
          e_preventDefault(e2);
          if (!modifier && +new Date - 200 < startTime)
            extendSelection(cm.doc, start);
          // Work around unexplainable focus problem in IE9 (#2127) and Chrome (#3081)
          if (webkit || ie && ie_version == 9)
            setTimeout(function() {document.body.focus(); display.input.focus();}, 20);
          else
            display.input.focus();
        }
      });
      // Let the drag handler handle this.
      if (webkit) display.scroller.draggable = true;
      cm.state.draggingText = dragEnd;
      // IE's approach to draggable
      if (display.scroller.dragDrop) display.scroller.dragDrop();
      on(document, "mouseup", dragEnd);
      on(display.scroller, "drop", dragEnd);
    }
  
    // Normal selection, as opposed to text dragging.
    function leftButtonSelect(cm, e, start, type, addNew) {
      var display = cm.display, doc = cm.doc;
      e_preventDefault(e);
  
      var ourRange, ourIndex, startSel = doc.sel, ranges = startSel.ranges;
      if (addNew && !e.shiftKey) {
        ourIndex = doc.sel.contains(start);
        if (ourIndex > -1)
          ourRange = ranges[ourIndex];
        else
          ourRange = new Range(start, start);
      } else {
        ourRange = doc.sel.primary();
        ourIndex = doc.sel.primIndex;
      }
  
      if (e.altKey) {
        type = "rect";
        if (!addNew) ourRange = new Range(start, start);
        start = posFromMouse(cm, e, true, true);
        ourIndex = -1;
      } else if (type == "double") {
        var word = cm.findWordAt(start);
        if (cm.display.shift || doc.extend)
          ourRange = extendRange(doc, ourRange, word.anchor, word.head);
        else
          ourRange = word;
      } else if (type == "triple") {
        var line = new Range(Pos(start.line, 0), clipPos(doc, Pos(start.line + 1, 0)));
        if (cm.display.shift || doc.extend)
          ourRange = extendRange(doc, ourRange, line.anchor, line.head);
        else
          ourRange = line;
      } else {
        ourRange = extendRange(doc, ourRange, start);
      }
  
      if (!addNew) {
        ourIndex = 0;
        setSelection(doc, new Selection([ourRange], 0), sel_mouse);
        startSel = doc.sel;
      } else if (ourIndex == -1) {
        ourIndex = ranges.length;
        setSelection(doc, normalizeSelection(ranges.concat([ourRange]), ourIndex),
                     {scroll: false, origin: "*mouse"});
      } else if (ranges.length > 1 && ranges[ourIndex].empty() && type == "single" && !e.shiftKey) {
        setSelection(doc, normalizeSelection(ranges.slice(0, ourIndex).concat(ranges.slice(ourIndex + 1)), 0),
                     {scroll: false, origin: "*mouse"});
        startSel = doc.sel;
      } else {
        replaceOneSelection(doc, ourIndex, ourRange, sel_mouse);
      }
  
      var lastPos = start;
      function extendTo(pos) {
        if (cmp(lastPos, pos) == 0) return;
        lastPos = pos;
  
        if (type == "rect") {
          var ranges = [], tabSize = cm.options.tabSize;
          var startCol = countColumn(getLine(doc, start.line).text, start.ch, tabSize);
          var posCol = countColumn(getLine(doc, pos.line).text, pos.ch, tabSize);
          var left = Math.min(startCol, posCol), right = Math.max(startCol, posCol);
          for (var line = Math.min(start.line, pos.line), end = Math.min(cm.lastLine(), Math.max(start.line, pos.line));
               line <= end; line++) {
            var text = getLine(doc, line).text, leftPos = findColumn(text, left, tabSize);
            if (left == right)
              ranges.push(new Range(Pos(line, leftPos), Pos(line, leftPos)));
            else if (text.length > leftPos)
              ranges.push(new Range(Pos(line, leftPos), Pos(line, findColumn(text, right, tabSize))));
          }
          if (!ranges.length) ranges.push(new Range(start, start));
          setSelection(doc, normalizeSelection(startSel.ranges.slice(0, ourIndex).concat(ranges), ourIndex),
                       {origin: "*mouse", scroll: false});
          cm.scrollIntoView(pos);
        } else {
          var oldRange = ourRange;
          var anchor = oldRange.anchor, head = pos;
          if (type != "single") {
            if (type == "double")
              var range = cm.findWordAt(pos);
            else
              var range = new Range(Pos(pos.line, 0), clipPos(doc, Pos(pos.line + 1, 0)));
            if (cmp(range.anchor, anchor) > 0) {
              head = range.head;
              anchor = minPos(oldRange.from(), range.anchor);
            } else {
              head = range.anchor;
              anchor = maxPos(oldRange.to(), range.head);
            }
          }
          var ranges = startSel.ranges.slice(0);
          ranges[ourIndex] = new Range(clipPos(doc, anchor), head);
          setSelection(doc, normalizeSelection(ranges, ourIndex), sel_mouse);
        }
      }
  
      var editorSize = display.wrapper.getBoundingClientRect();
      // Used to ensure timeout re-tries don't fire when another extend
      // happened in the meantime (clearTimeout isn't reliable -- at
      // least on Chrome, the timeouts still happen even when cleared,
      // if the clear happens after their scheduled firing time).
      var counter = 0;
  
      function extend(e) {
        var curCount = ++counter;
        var cur = posFromMouse(cm, e, true, type == "rect");
        if (!cur) return;
        if (cmp(cur, lastPos) != 0) {
          cm.curOp.focus = activeElt();
          extendTo(cur);
          var visible = visibleLines(display, doc);
          if (cur.line >= visible.to || cur.line < visible.from)
            setTimeout(operation(cm, function(){if (counter == curCount) extend(e);}), 150);
        } else {
          var outside = e.clientY < editorSize.top ? -20 : e.clientY > editorSize.bottom ? 20 : 0;
          if (outside) setTimeout(operation(cm, function() {
            if (counter != curCount) return;
            display.scroller.scrollTop += outside;
            extend(e);
          }), 50);
        }
      }
  
      function done(e) {
        cm.state.selectingText = false;
        counter = Infinity;
        e_preventDefault(e);
        display.input.focus();
        off(document, "mousemove", move);
        off(document, "mouseup", up);
        doc.history.lastSelOrigin = null;
      }
  
      var move = operation(cm, function(e) {
        if (!e_button(e)) done(e);
        else extend(e);
      });
      var up = operation(cm, done);
      cm.state.selectingText = up;
      on(document, "mousemove", move);
      on(document, "mouseup", up);
    }
  
    // Determines whether an event happened in the gutter, and fires the
    // handlers for the corresponding event.
    function gutterEvent(cm, e, type, prevent) {
      try { var mX = e.clientX, mY = e.clientY; }
      catch(e) { return false; }
      if (mX >= Math.floor(cm.display.gutters.getBoundingClientRect().right)) return false;
      if (prevent) e_preventDefault(e);
  
      var display = cm.display;
      var lineBox = display.lineDiv.getBoundingClientRect();
  
      if (mY > lineBox.bottom || !hasHandler(cm, type)) return e_defaultPrevented(e);
      mY -= lineBox.top - display.viewOffset;
  
      for (var i = 0; i < cm.options.gutters.length; ++i) {
        var g = display.gutters.childNodes[i];
        if (g && g.getBoundingClientRect().right >= mX) {
          var line = lineAtHeight(cm.doc, mY);
          var gutter = cm.options.gutters[i];
          signal(cm, type, cm, line, gutter, e);
          return e_defaultPrevented(e);
        }
      }
    }
  
    function clickInGutter(cm, e) {
      return gutterEvent(cm, e, "gutterClick", true);
    }
  
    // Kludge to work around strange IE behavior where it'll sometimes
    // re-fire a series of drag-related events right after the drop (#1551)
    var lastDrop = 0;
  
    function onDrop(e) {
      var cm = this;
      clearDragCursor(cm);
      if (signalDOMEvent(cm, e) || eventInWidget(cm.display, e))
        return;
      e_preventDefault(e);
      if (ie) lastDrop = +new Date;
      var pos = posFromMouse(cm, e, true), files = e.dataTransfer.files;
      if (!pos || cm.isReadOnly()) return;
      // Might be a file drop, in which case we simply extract the text
      // and insert it.
      if (files && files.length && window.FileReader && window.File) {
        var n = files.length, text = Array(n), read = 0;
        var loadFile = function(file, i) {
          if (cm.options.allowDropFileTypes &&
              indexOf(cm.options.allowDropFileTypes, file.type) == -1)
            return;
  
          var reader = new FileReader;
          reader.onload = operation(cm, function() {
            var content = reader.result;
            if (/[\x00-\x08\x0e-\x1f]{2}/.test(content)) content = "";
            text[i] = content;
            if (++read == n) {
              pos = clipPos(cm.doc, pos);
              var change = {from: pos, to: pos,
                            text: cm.doc.splitLines(text.join(cm.doc.lineSeparator())),
                            origin: "paste"};
              makeChange(cm.doc, change);
              setSelectionReplaceHistory(cm.doc, simpleSelection(pos, changeEnd(change)));
            }
          });
          reader.readAsText(file);
        };
        for (var i = 0; i < n; ++i) loadFile(files[i], i);
      } else { // Normal drop
        // Don't do a replace if the drop happened inside of the selected text.
        if (cm.state.draggingText && cm.doc.sel.contains(pos) > -1) {
          cm.state.draggingText(e);
          // Ensure the editor is re-focused
          setTimeout(function() {cm.display.input.focus();}, 20);
          return;
        }
        try {
          var text = e.dataTransfer.getData("Text");
          if (text) {
            if (cm.state.draggingText && !(mac ? e.altKey : e.ctrlKey))
              var selected = cm.listSelections();
            setSelectionNoUndo(cm.doc, simpleSelection(pos, pos));
            if (selected) for (var i = 0; i < selected.length; ++i)
              replaceRange(cm.doc, "", selected[i].anchor, selected[i].head, "drag");
            cm.replaceSelection(text, "around", "paste");
            cm.display.input.focus();
          }
        }
        catch(e){}
      }
    }
  
    function onDragStart(cm, e) {
      if (ie && (!cm.state.draggingText || +new Date - lastDrop < 100)) { e_stop(e); return; }
      if (signalDOMEvent(cm, e) || eventInWidget(cm.display, e)) return;
  
      e.dataTransfer.setData("Text", cm.getSelection());
  
      // Use dummy image instead of default browsers image.
      // Recent Safari (~6.0.2) have a tendency to segfault when this happens, so we don't do it there.
      if (e.dataTransfer.setDragImage && !safari) {
        var img = elt("img", null, null, "position: fixed; left: 0; top: 0;");
        img.src = "data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==";
        if (presto) {
          img.width = img.height = 1;
          cm.display.wrapper.appendChild(img);
          // Force a relayout, or Opera won't use our image for some obscure reason
          img._top = img.offsetTop;
        }
        e.dataTransfer.setDragImage(img, 0, 0);
        if (presto) img.parentNode.removeChild(img);
      }
    }
  
    function onDragOver(cm, e) {
      var pos = posFromMouse(cm, e);
      if (!pos) return;
      var frag = document.createDocumentFragment();
      drawSelectionCursor(cm, pos, frag);
      if (!cm.display.dragCursor) {
        cm.display.dragCursor = elt("div", null, "CodeMirror-cursors CodeMirror-dragcursors");
        cm.display.lineSpace.insertBefore(cm.display.dragCursor, cm.display.cursorDiv);
      }
      removeChildrenAndAdd(cm.display.dragCursor, frag);
    }
  
    function clearDragCursor(cm) {
      if (cm.display.dragCursor) {
        cm.display.lineSpace.removeChild(cm.display.dragCursor);
        cm.display.dragCursor = null;
      }
    }
  
    // SCROLL EVENTS
  
    // Sync the scrollable area and scrollbars, ensure the viewport
    // covers the visible area.
    function setScrollTop(cm, val) {
      if (Math.abs(cm.doc.scrollTop - val) < 2) return;
      cm.doc.scrollTop = val;
      if (!gecko) updateDisplaySimple(cm, {top: val});
      if (cm.display.scroller.scrollTop != val) cm.display.scroller.scrollTop = val;
      cm.display.scrollbars.setScrollTop(val);
      if (gecko) updateDisplaySimple(cm);
      startWorker(cm, 100);
    }
    // Sync scroller and scrollbar, ensure the gutter elements are
    // aligned.
    function setScrollLeft(cm, val, isScroller) {
      if (isScroller ? val == cm.doc.scrollLeft : Math.abs(cm.doc.scrollLeft - val) < 2) return;
      val = Math.min(val, cm.display.scroller.scrollWidth - cm.display.scroller.clientWidth);
      cm.doc.scrollLeft = val;
      alignHorizontally(cm);
      if (cm.display.scroller.scrollLeft != val) cm.display.scroller.scrollLeft = val;
      cm.display.scrollbars.setScrollLeft(val);
    }
  
    // Since the delta values reported on mouse wheel events are
    // unstandardized between browsers and even browser versions, and
    // generally horribly unpredictable, this code starts by measuring
    // the scroll effect that the first few mouse wheel events have,
    // and, from that, detects the way it can convert deltas to pixel
    // offsets afterwards.
    //
    // The reason we want to know the amount a wheel event will scroll
    // is that it gives us a chance to update the display before the
    // actual scrolling happens, reducing flickering.
  
    var wheelSamples = 0, wheelPixelsPerUnit = null;
    // Fill in a browser-detected starting value on browsers where we
    // know one. These don't have to be accurate -- the result of them
    // being wrong would just be a slight flicker on the first wheel
    // scroll (if it is large enough).
    if (ie) wheelPixelsPerUnit = -.53;
    else if (gecko) wheelPixelsPerUnit = 15;
    else if (chrome) wheelPixelsPerUnit = -.7;
    else if (safari) wheelPixelsPerUnit = -1/3;
  
    var wheelEventDelta = function(e) {
      var dx = e.wheelDeltaX, dy = e.wheelDeltaY;
      if (dx == null && e.detail && e.axis == e.HORIZONTAL_AXIS) dx = e.detail;
      if (dy == null && e.detail && e.axis == e.VERTICAL_AXIS) dy = e.detail;
      else if (dy == null) dy = e.wheelDelta;
      return {x: dx, y: dy};
    };
    CodeMirror.wheelEventPixels = function(e) {
      var delta = wheelEventDelta(e);
      delta.x *= wheelPixelsPerUnit;
      delta.y *= wheelPixelsPerUnit;
      return delta;
    };
  
    function onScrollWheel(cm, e) {
      var delta = wheelEventDelta(e), dx = delta.x, dy = delta.y;
  
      var display = cm.display, scroll = display.scroller;
      // Quit if there's nothing to scroll here
      var canScrollX = scroll.scrollWidth > scroll.clientWidth;
      var canScrollY = scroll.scrollHeight > scroll.clientHeight;
      if (!(dx && canScrollX || dy && canScrollY)) return;
  
      // Webkit browsers on OS X abort momentum scrolls when the target
      // of the scroll event is removed from the scrollable element.
      // This hack (see related code in patchDisplay) makes sure the
      // element is kept around.
      if (dy && mac && webkit) {
        outer: for (var cur = e.target, view = display.view; cur != scroll; cur = cur.parentNode) {
          for (var i = 0; i < view.length; i++) {
            if (view[i].node == cur) {
              cm.display.currentWheelTarget = cur;
              break outer;
            }
          }
        }
      }
  
      // On some browsers, horizontal scrolling will cause redraws to
      // happen before the gutter has been realigned, causing it to
      // wriggle around in a most unseemly way. When we have an
      // estimated pixels/delta value, we just handle horizontal
      // scrolling entirely here. It'll be slightly off from native, but
      // better than glitching out.
      if (dx && !gecko && !presto && wheelPixelsPerUnit != null) {
        if (dy && canScrollY)
          setScrollTop(cm, Math.max(0, Math.min(scroll.scrollTop + dy * wheelPixelsPerUnit, scroll.scrollHeight - scroll.clientHeight)));
        setScrollLeft(cm, Math.max(0, Math.min(scroll.scrollLeft + dx * wheelPixelsPerUnit, scroll.scrollWidth - scroll.clientWidth)));
        // Only prevent default scrolling if vertical scrolling is
        // actually possible. Otherwise, it causes vertical scroll
        // jitter on OSX trackpads when deltaX is small and deltaY
        // is large (issue #3579)
        if (!dy || (dy && canScrollY))
          e_preventDefault(e);
        display.wheelStartX = null; // Abort measurement, if in progress
        return;
      }
  
      // 'Project' the visible viewport to cover the area that is being
      // scrolled into view (if we know enough to estimate it).
      if (dy && wheelPixelsPerUnit != null) {
        var pixels = dy * wheelPixelsPerUnit;
        var top = cm.doc.scrollTop, bot = top + display.wrapper.clientHeight;
        if (pixels < 0) top = Math.max(0, top + pixels - 50);
        else bot = Math.min(cm.doc.height, bot + pixels + 50);
        updateDisplaySimple(cm, {top: top, bottom: bot});
      }
  
      if (wheelSamples < 20) {
        if (display.wheelStartX == null) {
          display.wheelStartX = scroll.scrollLeft; display.wheelStartY = scroll.scrollTop;
          display.wheelDX = dx; display.wheelDY = dy;
          setTimeout(function() {
            if (display.wheelStartX == null) return;
            var movedX = scroll.scrollLeft - display.wheelStartX;
            var movedY = scroll.scrollTop - display.wheelStartY;
            var sample = (movedY && display.wheelDY && movedY / display.wheelDY) ||
              (movedX && display.wheelDX && movedX / display.wheelDX);
            display.wheelStartX = display.wheelStartY = null;
            if (!sample) return;
            wheelPixelsPerUnit = (wheelPixelsPerUnit * wheelSamples + sample) / (wheelSamples + 1);
            ++wheelSamples;
          }, 200);
        } else {
          display.wheelDX += dx; display.wheelDY += dy;
        }
      }
    }
  
    // KEY EVENTS
  
    // Run a handler that was bound to a key.
    function doHandleBinding(cm, bound, dropShift) {
      if (typeof bound == "string") {
        bound = commands[bound];
        if (!bound) return false;
      }
      // Ensure previous input has been read, so that the handler sees a
      // consistent view of the document
      cm.display.input.ensurePolled();
      var prevShift = cm.display.shift, done = false;
      try {
        if (cm.isReadOnly()) cm.state.suppressEdits = true;
        if (dropShift) cm.display.shift = false;
        done = bound(cm) != Pass;
      } finally {
        cm.display.shift = prevShift;
        cm.state.suppressEdits = false;
      }
      return done;
    }
  
    function lookupKeyForEditor(cm, name, handle) {
      for (var i = 0; i < cm.state.keyMaps.length; i++) {
        var result = lookupKey(name, cm.state.keyMaps[i], handle, cm);
        if (result) return result;
      }
      return (cm.options.extraKeys && lookupKey(name, cm.options.extraKeys, handle, cm))
        || lookupKey(name, cm.options.keyMap, handle, cm);
    }
  
    var stopSeq = new Delayed;
    function dispatchKey(cm, name, e, handle) {
      var seq = cm.state.keySeq;
      if (seq) {
        if (isModifierKey(name)) return "handled";
        stopSeq.set(50, function() {
          if (cm.state.keySeq == seq) {
            cm.state.keySeq = null;
            cm.display.input.reset();
          }
        });
        name = seq + " " + name;
      }
      var result = lookupKeyForEditor(cm, name, handle);
  
      if (result == "multi")
        cm.state.keySeq = name;
      if (result == "handled")
        signalLater(cm, "keyHandled", cm, name, e);
  
      if (result == "handled" || result == "multi") {
        e_preventDefault(e);
        restartBlink(cm);
      }
  
      if (seq && !result && /\'$/.test(name)) {
        e_preventDefault(e);
        return true;
      }
      return !!result;
    }
  
    // Handle a key from the keydown event.
    function handleKeyBinding(cm, e) {
      var name = keyName(e, true);
      if (!name) return false;
  
      if (e.shiftKey && !cm.state.keySeq) {
        // First try to resolve full name (including 'Shift-'). Failing
        // that, see if there is a cursor-motion command (starting with
        // 'go') bound to the keyname without 'Shift-'.
        return dispatchKey(cm, "Shift-" + name, e, function(b) {return doHandleBinding(cm, b, true);})
            || dispatchKey(cm, name, e, function(b) {
                 if (typeof b == "string" ? /^go[A-Z]/.test(b) : b.motion)
                   return doHandleBinding(cm, b);
               });
      } else {
        return dispatchKey(cm, name, e, function(b) { return doHandleBinding(cm, b); });
      }
    }
  
    // Handle a key from the keypress event
    function handleCharBinding(cm, e, ch) {
      return dispatchKey(cm, "'" + ch + "'", e,
                         function(b) { return doHandleBinding(cm, b, true); });
    }
  
    var lastStoppedKey = null;
    function onKeyDown(e) {
      var cm = this;
      cm.curOp.focus = activeElt();
      if (signalDOMEvent(cm, e)) return;
      // IE does strange things with escape.
      if (ie && ie_version < 11 && e.keyCode == 27) e.returnValue = false;
      var code = e.keyCode;
      cm.display.shift = code == 16 || e.shiftKey;
      var handled = handleKeyBinding(cm, e);
      if (presto) {
        lastStoppedKey = handled ? code : null;
        // Opera has no cut event... we try to at least catch the key combo
        if (!handled && code == 88 && !hasCopyEvent && (mac ? e.metaKey : e.ctrlKey))
          cm.replaceSelection("", null, "cut");
      }
  
      // Turn mouse into crosshair when Alt is held on Mac.
      if (code == 18 && !/\bCodeMirror-crosshair\b/.test(cm.display.lineDiv.className))
        showCrossHair(cm);
    }
  
    function showCrossHair(cm) {
      var lineDiv = cm.display.lineDiv;
      addClass(lineDiv, "CodeMirror-crosshair");
  
      function up(e) {
        if (e.keyCode == 18 || !e.altKey) {
          rmClass(lineDiv, "CodeMirror-crosshair");
          off(document, "keyup", up);
          off(document, "mouseover", up);
        }
      }
      on(document, "keyup", up);
      on(document, "mouseover", up);
    }
  
    function onKeyUp(e) {
      if (e.keyCode == 16) this.doc.sel.shift = false;
      signalDOMEvent(this, e);
    }
  
    function onKeyPress(e) {
      var cm = this;
      if (eventInWidget(cm.display, e) || signalDOMEvent(cm, e) || e.ctrlKey && !e.altKey || mac && e.metaKey) return;
      var keyCode = e.keyCode, charCode = e.charCode;
      if (presto && keyCode == lastStoppedKey) {lastStoppedKey = null; e_preventDefault(e); return;}
      if ((presto && (!e.which || e.which < 10)) && handleKeyBinding(cm, e)) return;
      var ch = String.fromCharCode(charCode == null ? keyCode : charCode);
      if (handleCharBinding(cm, e, ch)) return;
      cm.display.input.onKeyPress(e);
    }
  
    // FOCUS/BLUR EVENTS
  
    function delayBlurEvent(cm) {
      cm.state.delayingBlurEvent = true;
      setTimeout(function() {
        if (cm.state.delayingBlurEvent) {
          cm.state.delayingBlurEvent = false;
          onBlur(cm);
        }
      }, 100);
    }
  
    function onFocus(cm) {
      if (cm.state.delayingBlurEvent) cm.state.delayingBlurEvent = false;
  
      if (cm.options.readOnly == "nocursor") return;
      if (!cm.state.focused) {
        signal(cm, "focus", cm);
        cm.state.focused = true;
        addClass(cm.display.wrapper, "CodeMirror-focused");
        // This test prevents this from firing when a context
        // menu is closed (since the input reset would kill the
        // select-all detection hack)
        if (!cm.curOp && cm.display.selForContextMenu != cm.doc.sel) {
          cm.display.input.reset();
          if (webkit) setTimeout(function() { cm.display.input.reset(true); }, 20); // Issue #1730
        }
        cm.display.input.receivedFocus();
      }
      restartBlink(cm);
    }
    function onBlur(cm) {
      if (cm.state.delayingBlurEvent) return;
  
      if (cm.state.focused) {
        signal(cm, "blur", cm);
        cm.state.focused = false;
        rmClass(cm.display.wrapper, "CodeMirror-focused");
      }
      clearInterval(cm.display.blinker);
      setTimeout(function() {if (!cm.state.focused) cm.display.shift = false;}, 150);
    }
  
    // CONTEXT MENU HANDLING
  
    // To make the context menu work, we need to briefly unhide the
    // textarea (making it as unobtrusive as possible) to let the
    // right-click take effect on it.
    function onContextMenu(cm, e) {
      if (eventInWidget(cm.display, e) || contextMenuInGutter(cm, e)) return;
      if (signalDOMEvent(cm, e, "contextmenu")) return;
      cm.display.input.onContextMenu(e);
    }
  
    function contextMenuInGutter(cm, e) {
      if (!hasHandler(cm, "gutterContextMenu")) return false;
      return gutterEvent(cm, e, "gutterContextMenu", false);
    }
  
    // UPDATING
  
    // Compute the position of the end of a change (its 'to' property
    // refers to the pre-change end).
    var changeEnd = CodeMirror.changeEnd = function(change) {
      if (!change.text) return change.to;
      return Pos(change.from.line + change.text.length - 1,
                 lst(change.text).length + (change.text.length == 1 ? change.from.ch : 0));
    };
  
    // Adjust a position to refer to the post-change position of the
    // same text, or the end of the change if the change covers it.
    function adjustForChange(pos, change) {
      if (cmp(pos, change.from) < 0) return pos;
      if (cmp(pos, change.to) <= 0) return changeEnd(change);
  
      var line = pos.line + change.text.length - (change.to.line - change.from.line) - 1, ch = pos.ch;
      if (pos.line == change.to.line) ch += changeEnd(change).ch - change.to.ch;
      return Pos(line, ch);
    }
  
    function computeSelAfterChange(doc, change) {
      var out = [];
      for (var i = 0; i < doc.sel.ranges.length; i++) {
        var range = doc.sel.ranges[i];
        out.push(new Range(adjustForChange(range.anchor, change),
                           adjustForChange(range.head, change)));
      }
      return normalizeSelection(out, doc.sel.primIndex);
    }
  
    function offsetPos(pos, old, nw) {
      if (pos.line == old.line)
        return Pos(nw.line, pos.ch - old.ch + nw.ch);
      else
        return Pos(nw.line + (pos.line - old.line), pos.ch);
    }
  
    // Used by replaceSelections to allow moving the selection to the
    // start or around the replaced test. Hint may be "start" or "around".
    function computeReplacedSel(doc, changes, hint) {
      var out = [];
      var oldPrev = Pos(doc.first, 0), newPrev = oldPrev;
      for (var i = 0; i < changes.length; i++) {
        var change = changes[i];
        var from = offsetPos(change.from, oldPrev, newPrev);
        var to = offsetPos(changeEnd(change), oldPrev, newPrev);
        oldPrev = change.to;
        newPrev = to;
        if (hint == "around") {
          var range = doc.sel.ranges[i], inv = cmp(range.head, range.anchor) < 0;
          out[i] = new Range(inv ? to : from, inv ? from : to);
        } else {
          out[i] = new Range(from, from);
        }
      }
      return new Selection(out, doc.sel.primIndex);
    }
  
    // Allow "beforeChange" event handlers to influence a change
    function filterChange(doc, change, update) {
      var obj = {
        canceled: false,
        from: change.from,
        to: change.to,
        text: change.text,
        origin: change.origin,
        cancel: function() { this.canceled = true; }
      };
      if (update) obj.update = function(from, to, text, origin) {
        if (from) this.from = clipPos(doc, from);
        if (to) this.to = clipPos(doc, to);
        if (text) this.text = text;
        if (origin !== undefined) this.origin = origin;
      };
      signal(doc, "beforeChange", doc, obj);
      if (doc.cm) signal(doc.cm, "beforeChange", doc.cm, obj);
  
      if (obj.canceled) return null;
      return {from: obj.from, to: obj.to, text: obj.text, origin: obj.origin};
    }
  
    // Apply a change to a document, and add it to the document's
    // history, and propagating it to all linked documents.
    function makeChange(doc, change, ignoreReadOnly) {
      if (doc.cm) {
        if (!doc.cm.curOp) return operation(doc.cm, makeChange)(doc, change, ignoreReadOnly);
        if (doc.cm.state.suppressEdits) return;
      }
  
      if (hasHandler(doc, "beforeChange") || doc.cm && hasHandler(doc.cm, "beforeChange")) {
        change = filterChange(doc, change, true);
        if (!change) return;
      }
  
      // Possibly split or suppress the update based on the presence
      // of read-only spans in its range.
      var split = sawReadOnlySpans && !ignoreReadOnly && removeReadOnlyRanges(doc, change.from, change.to);
      if (split) {
        for (var i = split.length - 1; i >= 0; --i)
          makeChangeInner(doc, {from: split[i].from, to: split[i].to, text: i ? [""] : change.text});
      } else {
        makeChangeInner(doc, change);
      }
    }
  
    function makeChangeInner(doc, change) {
      if (change.text.length == 1 && change.text[0] == "" && cmp(change.from, change.to) == 0) return;
      var selAfter = computeSelAfterChange(doc, change);
      addChangeToHistory(doc, change, selAfter, doc.cm ? doc.cm.curOp.id : NaN);
  
      makeChangeSingleDoc(doc, change, selAfter, stretchSpansOverChange(doc, change));
      var rebased = [];
  
      linkedDocs(doc, function(doc, sharedHist) {
        if (!sharedHist && indexOf(rebased, doc.history) == -1) {
          rebaseHist(doc.history, change);
          rebased.push(doc.history);
        }
        makeChangeSingleDoc(doc, change, null, stretchSpansOverChange(doc, change));
      });
    }
  
    // Revert a change stored in a document's history.
    function makeChangeFromHistory(doc, type, allowSelectionOnly) {
      if (doc.cm && doc.cm.state.suppressEdits) return;
  
      var hist = doc.history, event, selAfter = doc.sel;
      var source = type == "undo" ? hist.done : hist.undone, dest = type == "undo" ? hist.undone : hist.done;
  
      // Verify that there is a useable event (so that ctrl-z won't
      // needlessly clear selection events)
      for (var i = 0; i < source.length; i++) {
        event = source[i];
        if (allowSelectionOnly ? event.ranges && !event.equals(doc.sel) : !event.ranges)
          break;
      }
      if (i == source.length) return;
      hist.lastOrigin = hist.lastSelOrigin = null;
  
      for (;;) {
        event = source.pop();
        if (event.ranges) {
          pushSelectionToHistory(event, dest);
          if (allowSelectionOnly && !event.equals(doc.sel)) {
            setSelection(doc, event, {clearRedo: false});
            return;
          }
          selAfter = event;
        }
        else break;
      }
  
      // Build up a reverse change object to add to the opposite history
      // stack (redo when undoing, and vice versa).
      var antiChanges = [];
      pushSelectionToHistory(selAfter, dest);
      dest.push({changes: antiChanges, generation: hist.generation});
      hist.generation = event.generation || ++hist.maxGeneration;
  
      var filter = hasHandler(doc, "beforeChange") || doc.cm && hasHandler(doc.cm, "beforeChange");
  
      for (var i = event.changes.length - 1; i >= 0; --i) {
        var change = event.changes[i];
        change.origin = type;
        if (filter && !filterChange(doc, change, false)) {
          source.length = 0;
          return;
        }
  
        antiChanges.push(historyChangeFromChange(doc, change));
  
        var after = i ? computeSelAfterChange(doc, change) : lst(source);
        makeChangeSingleDoc(doc, change, after, mergeOldSpans(doc, change));
        if (!i && doc.cm) doc.cm.scrollIntoView({from: change.from, to: changeEnd(change)});
        var rebased = [];
  
        // Propagate to the linked documents
        linkedDocs(doc, function(doc, sharedHist) {
          if (!sharedHist && indexOf(rebased, doc.history) == -1) {
            rebaseHist(doc.history, change);
            rebased.push(doc.history);
          }
          makeChangeSingleDoc(doc, change, null, mergeOldSpans(doc, change));
        });
      }
    }
  
    // Sub-views need their line numbers shifted when text is added
    // above or below them in the parent document.
    function shiftDoc(doc, distance) {
      if (distance == 0) return;
      doc.first += distance;
      doc.sel = new Selection(map(doc.sel.ranges, function(range) {
        return new Range(Pos(range.anchor.line + distance, range.anchor.ch),
                         Pos(range.head.line + distance, range.head.ch));
      }), doc.sel.primIndex);
      if (doc.cm) {
        regChange(doc.cm, doc.first, doc.first - distance, distance);
        for (var d = doc.cm.display, l = d.viewFrom; l < d.viewTo; l++)
          regLineChange(doc.cm, l, "gutter");
      }
    }
  
    // More lower-level change function, handling only a single document
    // (not linked ones).
    function makeChangeSingleDoc(doc, change, selAfter, spans) {
      if (doc.cm && !doc.cm.curOp)
        return operation(doc.cm, makeChangeSingleDoc)(doc, change, selAfter, spans);
  
      if (change.to.line < doc.first) {
        shiftDoc(doc, change.text.length - 1 - (change.to.line - change.from.line));
        return;
      }
      if (change.from.line > doc.lastLine()) return;
  
      // Clip the change to the size of this doc
      if (change.from.line < doc.first) {
        var shift = change.text.length - 1 - (doc.first - change.from.line);
        shiftDoc(doc, shift);
        change = {from: Pos(doc.first, 0), to: Pos(change.to.line + shift, change.to.ch),
                  text: [lst(change.text)], origin: change.origin};
      }
      var last = doc.lastLine();
      if (change.to.line > last) {
        change = {from: change.from, to: Pos(last, getLine(doc, last).text.length),
                  text: [change.text[0]], origin: change.origin};
      }
  
      change.removed = getBetween(doc, change.from, change.to);
  
      if (!selAfter) selAfter = computeSelAfterChange(doc, change);
      if (doc.cm) makeChangeSingleDocInEditor(doc.cm, change, spans);
      else updateDoc(doc, change, spans);
      setSelectionNoUndo(doc, selAfter, sel_dontScroll);
    }
  
    // Handle the interaction of a change to a document with the editor
    // that this document is part of.
    function makeChangeSingleDocInEditor(cm, change, spans) {
      var doc = cm.doc, display = cm.display, from = change.from, to = change.to;
  
      var recomputeMaxLength = false, checkWidthStart = from.line;
      if (!cm.options.lineWrapping) {
        checkWidthStart = lineNo(visualLine(getLine(doc, from.line)));
        doc.iter(checkWidthStart, to.line + 1, function(line) {
          if (line == display.maxLine) {
            recomputeMaxLength = true;
            return true;
          }
        });
      }
  
      if (doc.sel.contains(change.from, change.to) > -1)
        signalCursorActivity(cm);
  
      updateDoc(doc, change, spans, estimateHeight(cm));
  
      if (!cm.options.lineWrapping) {
        doc.iter(checkWidthStart, from.line + change.text.length, function(line) {
          var len = lineLength(line);
          if (len > display.maxLineLength) {
            display.maxLine = line;
            display.maxLineLength = len;
            display.maxLineChanged = true;
            recomputeMaxLength = false;
          }
        });
        if (recomputeMaxLength) cm.curOp.updateMaxLine = true;
      }
  
      // Adjust frontier, schedule worker
      doc.frontier = Math.min(doc.frontier, from.line);
      startWorker(cm, 400);
  
      var lendiff = change.text.length - (to.line - from.line) - 1;
      // Remember that these lines changed, for updating the display
      if (change.full)
        regChange(cm);
      else if (from.line == to.line && change.text.length == 1 && !isWholeLineUpdate(cm.doc, change))
        regLineChange(cm, from.line, "text");
      else
        regChange(cm, from.line, to.line + 1, lendiff);
  
      var changesHandler = hasHandler(cm, "changes"), changeHandler = hasHandler(cm, "change");
      if (changeHandler || changesHandler) {
        var obj = {
          from: from, to: to,
          text: change.text,
          removed: change.removed,
          origin: change.origin
        };
        if (changeHandler) signalLater(cm, "change", cm, obj);
        if (changesHandler) (cm.curOp.changeObjs || (cm.curOp.changeObjs = [])).push(obj);
      }
      cm.display.selForContextMenu = null;
    }
  
    function replaceRange(doc, code, from, to, origin) {
      if (!to) to = from;
      if (cmp(to, from) < 0) { var tmp = to; to = from; from = tmp; }
      if (typeof code == "string") code = doc.splitLines(code);
      makeChange(doc, {from: from, to: to, text: code, origin: origin});
    }
  
    // SCROLLING THINGS INTO VIEW
  
    // If an editor sits on the top or bottom of the window, partially
    // scrolled out of view, this ensures that the cursor is visible.
    function maybeScrollWindow(cm, coords) {
      if (signalDOMEvent(cm, "scrollCursorIntoView")) return;
  
      var display = cm.display, box = display.sizer.getBoundingClientRect(), doScroll = null;
      if (coords.top + box.top < 0) doScroll = true;
      else if (coords.bottom + box.top > (window.innerHeight || document.documentElement.clientHeight)) doScroll = false;
      if (doScroll != null && !phantom) {
        var scrollNode = elt("div", "\u200b", null, "position: absolute; top: " +
                             (coords.top - display.viewOffset - paddingTop(cm.display)) + "px; height: " +
                             (coords.bottom - coords.top + scrollGap(cm) + display.barHeight) + "px; left: " +
                             coords.left + "px; width: 2px;");
        cm.display.lineSpace.appendChild(scrollNode);
        scrollNode.scrollIntoView(doScroll);
        cm.display.lineSpace.removeChild(scrollNode);
      }
    }
  
    // Scroll a given position into view (immediately), verifying that
    // it actually became visible (as line heights are accurately
    // measured, the position of something may 'drift' during drawing).
    function scrollPosIntoView(cm, pos, end, margin) {
      if (margin == null) margin = 0;
      for (var limit = 0; limit < 5; limit++) {
        var changed = false, coords = cursorCoords(cm, pos);
        var endCoords = !end || end == pos ? coords : cursorCoords(cm, end);
        var scrollPos = calculateScrollPos(cm, Math.min(coords.left, endCoords.left),
                                           Math.min(coords.top, endCoords.top) - margin,
                                           Math.max(coords.left, endCoords.left),
                                           Math.max(coords.bottom, endCoords.bottom) + margin);
        var startTop = cm.doc.scrollTop, startLeft = cm.doc.scrollLeft;
        if (scrollPos.scrollTop != null) {
          setScrollTop(cm, scrollPos.scrollTop);
          if (Math.abs(cm.doc.scrollTop - startTop) > 1) changed = true;
        }
        if (scrollPos.scrollLeft != null) {
          setScrollLeft(cm, scrollPos.scrollLeft);
          if (Math.abs(cm.doc.scrollLeft - startLeft) > 1) changed = true;
        }
        if (!changed) break;
      }
      return coords;
    }
  
    // Scroll a given set of coordinates into view (immediately).
    function scrollIntoView(cm, x1, y1, x2, y2) {
      var scrollPos = calculateScrollPos(cm, x1, y1, x2, y2);
      if (scrollPos.scrollTop != null) setScrollTop(cm, scrollPos.scrollTop);
      if (scrollPos.scrollLeft != null) setScrollLeft(cm, scrollPos.scrollLeft);
    }
  
    // Calculate a new scroll position needed to scroll the given
    // rectangle into view. Returns an object with scrollTop and
    // scrollLeft properties. When these are undefined, the
    // vertical/horizontal position does not need to be adjusted.
    function calculateScrollPos(cm, x1, y1, x2, y2) {
      var display = cm.display, snapMargin = textHeight(cm.display);
      if (y1 < 0) y1 = 0;
      var screentop = cm.curOp && cm.curOp.scrollTop != null ? cm.curOp.scrollTop : display.scroller.scrollTop;
      var screen = displayHeight(cm), result = {};
      if (y2 - y1 > screen) y2 = y1 + screen;
      var docBottom = cm.doc.height + paddingVert(display);
      var atTop = y1 < snapMargin, atBottom = y2 > docBottom - snapMargin;
      if (y1 < screentop) {
        result.scrollTop = atTop ? 0 : y1;
      } else if (y2 > screentop + screen) {
        var newTop = Math.min(y1, (atBottom ? docBottom : y2) - screen);
        if (newTop != screentop) result.scrollTop = newTop;
      }
  
      var screenleft = cm.curOp && cm.curOp.scrollLeft != null ? cm.curOp.scrollLeft : display.scroller.scrollLeft;
      var screenw = displayWidth(cm) - (cm.options.fixedGutter ? display.gutters.offsetWidth : 0);
      var tooWide = x2 - x1 > screenw;
      if (tooWide) x2 = x1 + screenw;
      if (x1 < 10)
        result.scrollLeft = 0;
      else if (x1 < screenleft)
        result.scrollLeft = Math.max(0, x1 - (tooWide ? 0 : 10));
      else if (x2 > screenw + screenleft - 3)
        result.scrollLeft = x2 + (tooWide ? 0 : 10) - screenw;
      return result;
    }
  
    // Store a relative adjustment to the scroll position in the current
    // operation (to be applied when the operation finishes).
    function addToScrollPos(cm, left, top) {
      if (left != null || top != null) resolveScrollToPos(cm);
      if (left != null)
        cm.curOp.scrollLeft = (cm.curOp.scrollLeft == null ? cm.doc.scrollLeft : cm.curOp.scrollLeft) + left;
      if (top != null)
        cm.curOp.scrollTop = (cm.curOp.scrollTop == null ? cm.doc.scrollTop : cm.curOp.scrollTop) + top;
    }
  
    // Make sure that at the end of the operation the current cursor is
    // shown.
    function ensureCursorVisible(cm) {
      resolveScrollToPos(cm);
      var cur = cm.getCursor(), from = cur, to = cur;
      if (!cm.options.lineWrapping) {
        from = cur.ch ? Pos(cur.line, cur.ch - 1) : cur;
        to = Pos(cur.line, cur.ch + 1);
      }
      cm.curOp.scrollToPos = {from: from, to: to, margin: cm.options.cursorScrollMargin, isCursor: true};
    }
  
    // When an operation has its scrollToPos property set, and another
    // scroll action is applied before the end of the operation, this
    // 'simulates' scrolling that position into view in a cheap way, so
    // that the effect of intermediate scroll commands is not ignored.
    function resolveScrollToPos(cm) {
      var range = cm.curOp.scrollToPos;
      if (range) {
        cm.curOp.scrollToPos = null;
        var from = estimateCoords(cm, range.from), to = estimateCoords(cm, range.to);
        var sPos = calculateScrollPos(cm, Math.min(from.left, to.left),
                                      Math.min(from.top, to.top) - range.margin,
                                      Math.max(from.right, to.right),
                                      Math.max(from.bottom, to.bottom) + range.margin);
        cm.scrollTo(sPos.scrollLeft, sPos.scrollTop);
      }
    }
  
    // API UTILITIES
  
    // Indent the given line. The how parameter can be "smart",
    // "add"/null, "subtract", or "prev". When aggressive is false
    // (typically set to true for forced single-line indents), empty
    // lines are not indented, and places where the mode returns Pass
    // are left alone.
    function indentLine(cm, n, how, aggressive) {
      var doc = cm.doc, state;
      if (how == null) how = "add";
      if (how == "smart") {
        // Fall back to "prev" when the mode doesn't have an indentation
        // method.
        if (!doc.mode.indent) how = "prev";
        else state = getStateBefore(cm, n);
      }
  
      var tabSize = cm.options.tabSize;
      var line = getLine(doc, n), curSpace = countColumn(line.text, null, tabSize);
      if (line.stateAfter) line.stateAfter = null;
      var curSpaceString = line.text.match(/^\s*/)[0], indentation;
      if (!aggressive && !/\S/.test(line.text)) {
        indentation = 0;
        how = "not";
      } else if (how == "smart") {
        indentation = doc.mode.indent(state, line.text.slice(curSpaceString.length), line.text);
        if (indentation == Pass || indentation > 150) {
          if (!aggressive) return;
          how = "prev";
        }
      }
      if (how == "prev") {
        if (n > doc.first) indentation = countColumn(getLine(doc, n-1).text, null, tabSize);
        else indentation = 0;
      } else if (how == "add") {
        indentation = curSpace + cm.options.indentUnit;
      } else if (how == "subtract") {
        indentation = curSpace - cm.options.indentUnit;
      } else if (typeof how == "number") {
        indentation = curSpace + how;
      }
      indentation = Math.max(0, indentation);
  
      var indentString = "", pos = 0;
      if (cm.options.indentWithTabs)
        for (var i = Math.floor(indentation / tabSize); i; --i) {pos += tabSize; indentString += "\t";}
      if (pos < indentation) indentString += spaceStr(indentation - pos);
  
      if (indentString != curSpaceString) {
        replaceRange(doc, indentString, Pos(n, 0), Pos(n, curSpaceString.length), "+input");
        line.stateAfter = null;
        return true;
      } else {
        // Ensure that, if the cursor was in the whitespace at the start
        // of the line, it is moved to the end of that space.
        for (var i = 0; i < doc.sel.ranges.length; i++) {
          var range = doc.sel.ranges[i];
          if (range.head.line == n && range.head.ch < curSpaceString.length) {
            var pos = Pos(n, curSpaceString.length);
            replaceOneSelection(doc, i, new Range(pos, pos));
            break;
          }
        }
      }
    }
  
    // Utility for applying a change to a line by handle or number,
    // returning the number and optionally registering the line as
    // changed.
    function changeLine(doc, handle, changeType, op) {
      var no = handle, line = handle;
      if (typeof handle == "number") line = getLine(doc, clipLine(doc, handle));
      else no = lineNo(handle);
      if (no == null) return null;
      if (op(line, no) && doc.cm) regLineChange(doc.cm, no, changeType);
      return line;
    }
  
    // Helper for deleting text near the selection(s), used to implement
    // backspace, delete, and similar functionality.
    function deleteNearSelection(cm, compute) {
      var ranges = cm.doc.sel.ranges, kill = [];
      // Build up a set of ranges to kill first, merging overlapping
      // ranges.
      for (var i = 0; i < ranges.length; i++) {
        var toKill = compute(ranges[i]);
        while (kill.length && cmp(toKill.from, lst(kill).to) <= 0) {
          var replaced = kill.pop();
          if (cmp(replaced.from, toKill.from) < 0) {
            toKill.from = replaced.from;
            break;
          }
        }
        kill.push(toKill);
      }
      // Next, remove those actual ranges.
      runInOp(cm, function() {
        for (var i = kill.length - 1; i >= 0; i--)
          replaceRange(cm.doc, "", kill[i].from, kill[i].to, "+delete");
        ensureCursorVisible(cm);
      });
    }
  
    // Used for horizontal relative motion. Dir is -1 or 1 (left or
    // right), unit can be "char", "column" (like char, but doesn't
    // cross line boundaries), "word" (across next word), or "group" (to
    // the start of next group of word or non-word-non-whitespace
    // chars). The visually param controls whether, in right-to-left
    // text, direction 1 means to move towards the next index in the
    // string, or towards the character to the right of the current
    // position. The resulting position will have a hitSide=true
    // property if it reached the end of the document.
    function findPosH(doc, pos, dir, unit, visually) {
      var line = pos.line, ch = pos.ch, origDir = dir;
      var lineObj = getLine(doc, line);
      function findNextLine() {
        var l = line + dir;
        if (l < doc.first || l >= doc.first + doc.size) return false
        line = l;
        return lineObj = getLine(doc, l);
      }
      function moveOnce(boundToLine) {
        var next = (visually ? moveVisually : moveLogically)(lineObj, ch, dir, true);
        if (next == null) {
          if (!boundToLine && findNextLine()) {
            if (visually) ch = (dir < 0 ? lineRight : lineLeft)(lineObj);
            else ch = dir < 0 ? lineObj.text.length : 0;
          } else return false
        } else ch = next;
        return true;
      }
  
      if (unit == "char") {
        moveOnce()
      } else if (unit == "column") {
        moveOnce(true)
      } else if (unit == "word" || unit == "group") {
        var sawType = null, group = unit == "group";
        var helper = doc.cm && doc.cm.getHelper(pos, "wordChars");
        for (var first = true;; first = false) {
          if (dir < 0 && !moveOnce(!first)) break;
          var cur = lineObj.text.charAt(ch) || "\n";
          var type = isWordChar(cur, helper) ? "w"
            : group && cur == "\n" ? "n"
            : !group || /\s/.test(cur) ? null
            : "p";
          if (group && !first && !type) type = "s";
          if (sawType && sawType != type) {
            if (dir < 0) {dir = 1; moveOnce();}
            break;
          }
  
          if (type) sawType = type;
          if (dir > 0 && !moveOnce(!first)) break;
        }
      }
      var result = skipAtomic(doc, Pos(line, ch), pos, origDir, true);
      if (!cmp(pos, result)) result.hitSide = true;
      return result;
    }
  
    // For relative vertical movement. Dir may be -1 or 1. Unit can be
    // "page" or "line". The resulting position will have a hitSide=true
    // property if it reached the end of the document.
    function findPosV(cm, pos, dir, unit) {
      var doc = cm.doc, x = pos.left, y;
      if (unit == "page") {
        var pageSize = Math.min(cm.display.wrapper.clientHeight, window.innerHeight || document.documentElement.clientHeight);
        y = pos.top + dir * (pageSize - (dir < 0 ? 1.5 : .5) * textHeight(cm.display));
      } else if (unit == "line") {
        y = dir > 0 ? pos.bottom + 3 : pos.top - 3;
      }
      for (;;) {
        var target = coordsChar(cm, x, y);
        if (!target.outside) break;
        if (dir < 0 ? y <= 0 : y >= doc.height) { target.hitSide = true; break; }
        y += dir * 5;
      }
      return target;
    }
  
    // EDITOR METHODS
  
    // The publicly visible API. Note that methodOp(f) means
    // 'wrap f in an operation, performed on its `this` parameter'.
  
    // This is not the complete set of editor methods. Most of the
    // methods defined on the Doc type are also injected into
    // CodeMirror.prototype, for backwards compatibility and
    // convenience.
  
    CodeMirror.prototype = {
      constructor: CodeMirror,
      focus: function(){window.focus(); this.display.input.focus();},
  
      setOption: function(option, value) {
        var options = this.options, old = options[option];
        if (options[option] == value && option != "mode") return;
        options[option] = value;
        if (optionHandlers.hasOwnProperty(option))
          operation(this, optionHandlers[option])(this, value, old);
      },
  
      getOption: function(option) {return this.options[option];},
      getDoc: function() {return this.doc;},
  
      addKeyMap: function(map, bottom) {
        this.state.keyMaps[bottom ? "push" : "unshift"](getKeyMap(map));
      },
      removeKeyMap: function(map) {
        var maps = this.state.keyMaps;
        for (var i = 0; i < maps.length; ++i)
          if (maps[i] == map || maps[i].name == map) {
            maps.splice(i, 1);
            return true;
          }
      },
  
      addOverlay: methodOp(function(spec, options) {
        var mode = spec.token ? spec : CodeMirror.getMode(this.options, spec);
        if (mode.startState) throw new Error("Overlays may not be stateful.");
        this.state.overlays.push({mode: mode, modeSpec: spec, opaque: options && options.opaque});
        this.state.modeGen++;
        regChange(this);
      }),
      removeOverlay: methodOp(function(spec) {
        var overlays = this.state.overlays;
        for (var i = 0; i < overlays.length; ++i) {
          var cur = overlays[i].modeSpec;
          if (cur == spec || typeof spec == "string" && cur.name == spec) {
            overlays.splice(i, 1);
            this.state.modeGen++;
            regChange(this);
            return;
          }
        }
      }),
  
      indentLine: methodOp(function(n, dir, aggressive) {
        if (typeof dir != "string" && typeof dir != "number") {
          if (dir == null) dir = this.options.smartIndent ? "smart" : "prev";
          else dir = dir ? "add" : "subtract";
        }
        if (isLine(this.doc, n)) indentLine(this, n, dir, aggressive);
      }),
      indentSelection: methodOp(function(how) {
        var ranges = this.doc.sel.ranges, end = -1;
        for (var i = 0; i < ranges.length; i++) {
          var range = ranges[i];
          if (!range.empty()) {
            var from = range.from(), to = range.to();
            var start = Math.max(end, from.line);
            end = Math.min(this.lastLine(), to.line - (to.ch ? 0 : 1)) + 1;
            for (var j = start; j < end; ++j)
              indentLine(this, j, how);
            var newRanges = this.doc.sel.ranges;
            if (from.ch == 0 && ranges.length == newRanges.length && newRanges[i].from().ch > 0)
              replaceOneSelection(this.doc, i, new Range(from, newRanges[i].to()), sel_dontScroll);
          } else if (range.head.line > end) {
            indentLine(this, range.head.line, how, true);
            end = range.head.line;
            if (i == this.doc.sel.primIndex) ensureCursorVisible(this);
          }
        }
      }),
  
      // Fetch the parser token for a given character. Useful for hacks
      // that want to inspect the mode state (say, for completion).
      getTokenAt: function(pos, precise) {
        return takeToken(this, pos, precise);
      },
  
      getLineTokens: function(line, precise) {
        return takeToken(this, Pos(line), precise, true);
      },
  
      getTokenTypeAt: function(pos) {
        pos = clipPos(this.doc, pos);
        var styles = getLineStyles(this, getLine(this.doc, pos.line));
        var before = 0, after = (styles.length - 1) / 2, ch = pos.ch;
        var type;
        if (ch == 0) type = styles[2];
        else for (;;) {
          var mid = (before + after) >> 1;
          if ((mid ? styles[mid * 2 - 1] : 0) >= ch) after = mid;
          else if (styles[mid * 2 + 1] < ch) before = mid + 1;
          else { type = styles[mid * 2 + 2]; break; }
        }
        var cut = type ? type.indexOf("cm-overlay ") : -1;
        return cut < 0 ? type : cut == 0 ? null : type.slice(0, cut - 1);
      },
  
      getModeAt: function(pos) {
        var mode = this.doc.mode;
        if (!mode.innerMode) return mode;
        return CodeMirror.innerMode(mode, this.getTokenAt(pos).state).mode;
      },
  
      getHelper: function(pos, type) {
        return this.getHelpers(pos, type)[0];
      },
  
      getHelpers: function(pos, type) {
        var found = [];
        if (!helpers.hasOwnProperty(type)) return found;
        var help = helpers[type], mode = this.getModeAt(pos);
        if (typeof mode[type] == "string") {
          if (help[mode[type]]) found.push(help[mode[type]]);
        } else if (mode[type]) {
          for (var i = 0; i < mode[type].length; i++) {
            var val = help[mode[type][i]];
            if (val) found.push(val);
          }
        } else if (mode.helperType && help[mode.helperType]) {
          found.push(help[mode.helperType]);
        } else if (help[mode.name]) {
          found.push(help[mode.name]);
        }
        for (var i = 0; i < help._global.length; i++) {
          var cur = help._global[i];
          if (cur.pred(mode, this) && indexOf(found, cur.val) == -1)
            found.push(cur.val);
        }
        return found;
      },
  
      getStateAfter: function(line, precise) {
        var doc = this.doc;
        line = clipLine(doc, line == null ? doc.first + doc.size - 1: line);
        return getStateBefore(this, line + 1, precise);
      },
  
      cursorCoords: function(start, mode) {
        var pos, range = this.doc.sel.primary();
        if (start == null) pos = range.head;
        else if (typeof start == "object") pos = clipPos(this.doc, start);
        else pos = start ? range.from() : range.to();
        return cursorCoords(this, pos, mode || "page");
      },
  
      charCoords: function(pos, mode) {
        return charCoords(this, clipPos(this.doc, pos), mode || "page");
      },
  
      coordsChar: function(coords, mode) {
        coords = fromCoordSystem(this, coords, mode || "page");
        return coordsChar(this, coords.left, coords.top);
      },
  
      lineAtHeight: function(height, mode) {
        height = fromCoordSystem(this, {top: height, left: 0}, mode || "page").top;
        return lineAtHeight(this.doc, height + this.display.viewOffset);
      },
      heightAtLine: function(line, mode) {
        var end = false, lineObj;
        if (typeof line == "number") {
          var last = this.doc.first + this.doc.size - 1;
          if (line < this.doc.first) line = this.doc.first;
          else if (line > last) { line = last; end = true; }
          lineObj = getLine(this.doc, line);
        } else {
          lineObj = line;
        }
        return intoCoordSystem(this, lineObj, {top: 0, left: 0}, mode || "page").top +
          (end ? this.doc.height - heightAtLine(lineObj) : 0);
      },
  
      defaultTextHeight: function() { return textHeight(this.display); },
      defaultCharWidth: function() { return charWidth(this.display); },
  
      setGutterMarker: methodOp(function(line, gutterID, value) {
        return changeLine(this.doc, line, "gutter", function(line) {
          var markers = line.gutterMarkers || (line.gutterMarkers = {});
          markers[gutterID] = value;
          if (!value && isEmpty(markers)) line.gutterMarkers = null;
          return true;
        });
      }),
  
      clearGutter: methodOp(function(gutterID) {
        var cm = this, doc = cm.doc, i = doc.first;
        doc.iter(function(line) {
          if (line.gutterMarkers && line.gutterMarkers[gutterID]) {
            line.gutterMarkers[gutterID] = null;
            regLineChange(cm, i, "gutter");
            if (isEmpty(line.gutterMarkers)) line.gutterMarkers = null;
          }
          ++i;
        });
      }),
  
      lineInfo: function(line) {
        if (typeof line == "number") {
          if (!isLine(this.doc, line)) return null;
          var n = line;
          line = getLine(this.doc, line);
          if (!line) return null;
        } else {
          var n = lineNo(line);
          if (n == null) return null;
        }
        return {line: n, handle: line, text: line.text, gutterMarkers: line.gutterMarkers,
                textClass: line.textClass, bgClass: line.bgClass, wrapClass: line.wrapClass,
                widgets: line.widgets};
      },
  
      getViewport: function() { return {from: this.display.viewFrom, to: this.display.viewTo};},
  
      addWidget: function(pos, node, scroll, vert, horiz) {
        var display = this.display;
        pos = cursorCoords(this, clipPos(this.doc, pos));
        var top = pos.bottom, left = pos.left;
        node.style.position = "absolute";
        node.setAttribute("cm-ignore-events", "true");
        this.display.input.setUneditable(node);
        display.sizer.appendChild(node);
        if (vert == "over") {
          top = pos.top;
        } else if (vert == "above" || vert == "near") {
          var vspace = Math.max(display.wrapper.clientHeight, this.doc.height),
          hspace = Math.max(display.sizer.clientWidth, display.lineSpace.clientWidth);
          // Default to positioning above (if specified and possible); otherwise default to positioning below
          if ((vert == 'above' || pos.bottom + node.offsetHeight > vspace) && pos.top > node.offsetHeight)
            top = pos.top - node.offsetHeight;
          else if (pos.bottom + node.offsetHeight <= vspace)
            top = pos.bottom;
          if (left + node.offsetWidth > hspace)
            left = hspace - node.offsetWidth;
        }
        node.style.top = top + "px";
        node.style.left = node.style.right = "";
        if (horiz == "right") {
          left = display.sizer.clientWidth - node.offsetWidth;
          node.style.right = "0px";
        } else {
          if (horiz == "left") left = 0;
          else if (horiz == "middle") left = (display.sizer.clientWidth - node.offsetWidth) / 2;
          node.style.left = left + "px";
        }
        if (scroll)
          scrollIntoView(this, left, top, left + node.offsetWidth, top + node.offsetHeight);
      },
  
      triggerOnKeyDown: methodOp(onKeyDown),
      triggerOnKeyPress: methodOp(onKeyPress),
      triggerOnKeyUp: onKeyUp,
  
      execCommand: function(cmd) {
        if (commands.hasOwnProperty(cmd))
          return commands[cmd].call(null, this);
      },
  
      triggerElectric: methodOp(function(text) { triggerElectric(this, text); }),
  
      findPosH: function(from, amount, unit, visually) {
        var dir = 1;
        if (amount < 0) { dir = -1; amount = -amount; }
        for (var i = 0, cur = clipPos(this.doc, from); i < amount; ++i) {
          cur = findPosH(this.doc, cur, dir, unit, visually);
          if (cur.hitSide) break;
        }
        return cur;
      },
  
      moveH: methodOp(function(dir, unit) {
        var cm = this;
        cm.extendSelectionsBy(function(range) {
          if (cm.display.shift || cm.doc.extend || range.empty())
            return findPosH(cm.doc, range.head, dir, unit, cm.options.rtlMoveVisually);
          else
            return dir < 0 ? range.from() : range.to();
        }, sel_move);
      }),
  
      deleteH: methodOp(function(dir, unit) {
        var sel = this.doc.sel, doc = this.doc;
        if (sel.somethingSelected())
          doc.replaceSelection("", null, "+delete");
        else
          deleteNearSelection(this, function(range) {
            var other = findPosH(doc, range.head, dir, unit, false);
            return dir < 0 ? {from: other, to: range.head} : {from: range.head, to: other};
          });
      }),
  
      findPosV: function(from, amount, unit, goalColumn) {
        var dir = 1, x = goalColumn;
        if (amount < 0) { dir = -1; amount = -amount; }
        for (var i = 0, cur = clipPos(this.doc, from); i < amount; ++i) {
          var coords = cursorCoords(this, cur, "div");
          if (x == null) x = coords.left;
          else coords.left = x;
          cur = findPosV(this, coords, dir, unit);
          if (cur.hitSide) break;
        }
        return cur;
      },
  
      moveV: methodOp(function(dir, unit) {
        var cm = this, doc = this.doc, goals = [];
        var collapse = !cm.display.shift && !doc.extend && doc.sel.somethingSelected();
        doc.extendSelectionsBy(function(range) {
          if (collapse)
            return dir < 0 ? range.from() : range.to();
          var headPos = cursorCoords(cm, range.head, "div");
          if (range.goalColumn != null) headPos.left = range.goalColumn;
          goals.push(headPos.left);
          var pos = findPosV(cm, headPos, dir, unit);
          if (unit == "page" && range == doc.sel.primary())
            addToScrollPos(cm, null, charCoords(cm, pos, "div").top - headPos.top);
          return pos;
        }, sel_move);
        if (goals.length) for (var i = 0; i < doc.sel.ranges.length; i++)
          doc.sel.ranges[i].goalColumn = goals[i];
      }),
  
      // Find the word at the given position (as returned by coordsChar).
      findWordAt: function(pos) {
        var doc = this.doc, line = getLine(doc, pos.line).text;
        var start = pos.ch, end = pos.ch;
        if (line) {
          var helper = this.getHelper(pos, "wordChars");
          if ((pos.xRel < 0 || end == line.length) && start) --start; else ++end;
          var startChar = line.charAt(start);
          var check = isWordChar(startChar, helper)
            ? function(ch) { return isWordChar(ch, helper); }
            : /\s/.test(startChar) ? function(ch) {return /\s/.test(ch);}
            : function(ch) {return !/\s/.test(ch) && !isWordChar(ch);};
          while (start > 0 && check(line.charAt(start - 1))) --start;
          while (end < line.length && check(line.charAt(end))) ++end;
        }
        return new Range(Pos(pos.line, start), Pos(pos.line, end));
      },
  
      toggleOverwrite: function(value) {
        if (value != null && value == this.state.overwrite) return;
        if (this.state.overwrite = !this.state.overwrite)
          addClass(this.display.cursorDiv, "CodeMirror-overwrite");
        else
          rmClass(this.display.cursorDiv, "CodeMirror-overwrite");
  
        signal(this, "overwriteToggle", this, this.state.overwrite);
      },
      hasFocus: function() { return this.display.input.getField() == activeElt(); },
      isReadOnly: function() { return !!(this.options.readOnly || this.doc.cantEdit); },
  
      scrollTo: methodOp(function(x, y) {
        if (x != null || y != null) resolveScrollToPos(this);
        if (x != null) this.curOp.scrollLeft = x;
        if (y != null) this.curOp.scrollTop = y;
      }),
      getScrollInfo: function() {
        var scroller = this.display.scroller;
        return {left: scroller.scrollLeft, top: scroller.scrollTop,
                height: scroller.scrollHeight - scrollGap(this) - this.display.barHeight,
                width: scroller.scrollWidth - scrollGap(this) - this.display.barWidth,
                clientHeight: displayHeight(this), clientWidth: displayWidth(this)};
      },
  
      scrollIntoView: methodOp(function(range, margin) {
        if (range == null) {
          range = {from: this.doc.sel.primary().head, to: null};
          if (margin == null) margin = this.options.cursorScrollMargin;
        } else if (typeof range == "number") {
          range = {from: Pos(range, 0), to: null};
        } else if (range.from == null) {
          range = {from: range, to: null};
        }
        if (!range.to) range.to = range.from;
        range.margin = margin || 0;
  
        if (range.from.line != null) {
          resolveScrollToPos(this);
          this.curOp.scrollToPos = range;
        } else {
          var sPos = calculateScrollPos(this, Math.min(range.from.left, range.to.left),
                                        Math.min(range.from.top, range.to.top) - range.margin,
                                        Math.max(range.from.right, range.to.right),
                                        Math.max(range.from.bottom, range.to.bottom) + range.margin);
          this.scrollTo(sPos.scrollLeft, sPos.scrollTop);
        }
      }),
  
      setSize: methodOp(function(width, height) {
        var cm = this;
        function interpret(val) {
          return typeof val == "number" || /^\d+$/.test(String(val)) ? val + "px" : val;
        }
        if (width != null) cm.display.wrapper.style.width = interpret(width);
        if (height != null) cm.display.wrapper.style.height = interpret(height);
        if (cm.options.lineWrapping) clearLineMeasurementCache(this);
        var lineNo = cm.display.viewFrom;
        cm.doc.iter(lineNo, cm.display.viewTo, function(line) {
          if (line.widgets) for (var i = 0; i < line.widgets.length; i++)
            if (line.widgets[i].noHScroll) { regLineChange(cm, lineNo, "widget"); break; }
          ++lineNo;
        });
        cm.curOp.forceUpdate = true;
        signal(cm, "refresh", this);
      }),
  
      operation: function(f){return runInOp(this, f);},
  
      refresh: methodOp(function() {
        var oldHeight = this.display.cachedTextHeight;
        regChange(this);
        this.curOp.forceUpdate = true;
        clearCaches(this);
        this.scrollTo(this.doc.scrollLeft, this.doc.scrollTop);
        updateGutterSpace(this);
        if (oldHeight == null || Math.abs(oldHeight - textHeight(this.display)) > .5)
          estimateLineHeights(this);
        signal(this, "refresh", this);
      }),
  
      swapDoc: methodOp(function(doc) {
        var old = this.doc;
        old.cm = null;
        attachDoc(this, doc);
        clearCaches(this);
        this.display.input.reset();
        this.scrollTo(doc.scrollLeft, doc.scrollTop);
        this.curOp.forceScroll = true;
        signalLater(this, "swapDoc", this, old);
        return old;
      }),
  
      getInputField: function(){return this.display.input.getField();},
      getWrapperElement: function(){return this.display.wrapper;},
      getScrollerElement: function(){return this.display.scroller;},
      getGutterElement: function(){return this.display.gutters;}
    };
    eventMixin(CodeMirror);
  
    // OPTION DEFAULTS
  
    // The default configuration options.
    var defaults = CodeMirror.defaults = {};
    // Functions to run when options are changed.
    var optionHandlers = CodeMirror.optionHandlers = {};
  
    function option(name, deflt, handle, notOnInit) {
      CodeMirror.defaults[name] = deflt;
      if (handle) optionHandlers[name] =
        notOnInit ? function(cm, val, old) {if (old != Init) handle(cm, val, old);} : handle;
    }
  
    // Passed to option handlers when there is no old value.
    var Init = CodeMirror.Init = {toString: function(){return "CodeMirror.Init";}};
  
    // These two are, on init, called from the constructor because they
    // have to be initialized before the editor can start at all.
    option("value", "", function(cm, val) {
      cm.setValue(val);
    }, true);
    option("mode", null, function(cm, val) {
      cm.doc.modeOption = val;
      loadMode(cm);
    }, true);
  
    option("indentUnit", 2, loadMode, true);
    option("indentWithTabs", false);
    option("smartIndent", true);
    option("tabSize", 4, function(cm) {
      resetModeState(cm);
      clearCaches(cm);
      regChange(cm);
    }, true);
    option("lineSeparator", null, function(cm, val) {
      cm.doc.lineSep = val;
      if (!val) return;
      var newBreaks = [], lineNo = cm.doc.first;
      cm.doc.iter(function(line) {
        for (var pos = 0;;) {
          var found = line.text.indexOf(val, pos);
          if (found == -1) break;
          pos = found + val.length;
          newBreaks.push(Pos(lineNo, found));
        }
        lineNo++;
      });
      for (var i = newBreaks.length - 1; i >= 0; i--)
        replaceRange(cm.doc, val, newBreaks[i], Pos(newBreaks[i].line, newBreaks[i].ch + val.length))
    });
    option("specialChars", /[\t\u0000-\u0019\u00ad\u200b-\u200f\u2028\u2029\ufeff]/g, function(cm, val, old) {
      cm.state.specialChars = new RegExp(val.source + (val.test("\t") ? "" : "|\t"), "g");
      if (old != CodeMirror.Init) cm.refresh();
    });
    option("specialCharPlaceholder", defaultSpecialCharPlaceholder, function(cm) {cm.refresh();}, true);
    option("electricChars", true);
    option("inputStyle", mobile ? "contenteditable" : "textarea", function() {
      throw new Error("inputStyle can not (yet) be changed in a running editor"); // FIXME
    }, true);
    option("rtlMoveVisually", !windows);
    option("wholeLineUpdateBefore", true);
  
    option("theme", "default", function(cm) {
      themeChanged(cm);
      guttersChanged(cm);
    }, true);
    option("keyMap", "default", function(cm, val, old) {
      var next = getKeyMap(val);
      var prev = old != CodeMirror.Init && getKeyMap(old);
      if (prev && prev.detach) prev.detach(cm, next);
      if (next.attach) next.attach(cm, prev || null);
    });
    option("extraKeys", null);
  
    option("lineWrapping", false, wrappingChanged, true);
    option("gutters", [], function(cm) {
      setGuttersForLineNumbers(cm.options);
      guttersChanged(cm);
    }, true);
    option("fixedGutter", true, function(cm, val) {
      cm.display.gutters.style.left = val ? compensateForHScroll(cm.display) + "px" : "0";
      cm.refresh();
    }, true);
    option("coverGutterNextToScrollbar", false, function(cm) {updateScrollbars(cm);}, true);
    option("scrollbarStyle", "native", function(cm) {
      initScrollbars(cm);
      updateScrollbars(cm);
      cm.display.scrollbars.setScrollTop(cm.doc.scrollTop);
      cm.display.scrollbars.setScrollLeft(cm.doc.scrollLeft);
    }, true);
    option("lineNumbers", false, function(cm) {
      setGuttersForLineNumbers(cm.options);
      guttersChanged(cm);
    }, true);
    option("firstLineNumber", 1, guttersChanged, true);
    option("lineNumberFormatter", function(integer) {return integer;}, guttersChanged, true);
    option("showCursorWhenSelecting", false, updateSelection, true);
  
    option("resetSelectionOnContextMenu", true);
    option("lineWiseCopyCut", true);
  
    option("readOnly", false, function(cm, val) {
      if (val == "nocursor") {
        onBlur(cm);
        cm.display.input.blur();
        cm.display.disabled = true;
      } else {
        cm.display.disabled = false;
      }
      cm.display.input.readOnlyChanged(val)
    });
    option("disableInput", false, function(cm, val) {if (!val) cm.display.input.reset();}, true);
    option("dragDrop", true, dragDropChanged);
    option("allowDropFileTypes", null);
  
    option("cursorBlinkRate", 530);
    option("cursorScrollMargin", 0);
    option("cursorHeight", 1, updateSelection, true);
    option("singleCursorHeightPerLine", true, updateSelection, true);
    option("workTime", 100);
    option("workDelay", 100);
    option("flattenSpans", true, resetModeState, true);
    option("addModeClass", false, resetModeState, true);
    option("pollInterval", 100);
    option("undoDepth", 200, function(cm, val){cm.doc.history.undoDepth = val;});
    option("historyEventDelay", 1250);
    option("viewportMargin", 10, function(cm){cm.refresh();}, true);
    option("maxHighlightLength", 10000, resetModeState, true);
    option("moveInputWithCursor", true, function(cm, val) {
      if (!val) cm.display.input.resetPosition();
    });
  
    option("tabindex", null, function(cm, val) {
      cm.display.input.getField().tabIndex = val || "";
    });
    option("autofocus", null);
  
    // MODE DEFINITION AND QUERYING
  
    // Known modes, by name and by MIME
    var modes = CodeMirror.modes = {}, mimeModes = CodeMirror.mimeModes = {};
  
    // Extra arguments are stored as the mode's dependencies, which is
    // used by (legacy) mechanisms like loadmode.js to automatically
    // load a mode. (Preferred mechanism is the require/define calls.)
    CodeMirror.defineMode = function(name, mode) {
      if (!CodeMirror.defaults.mode && name != "null") CodeMirror.defaults.mode = name;
      if (arguments.length > 2)
        mode.dependencies = Array.prototype.slice.call(arguments, 2);
      modes[name] = mode;
    };
  
    CodeMirror.defineMIME = function(mime, spec) {
      mimeModes[mime] = spec;
    };
  
    // Given a MIME type, a {name, ...options} config object, or a name
    // string, return a mode config object.
    CodeMirror.resolveMode = function(spec) {
      if (typeof spec == "string" && mimeModes.hasOwnProperty(spec)) {
        spec = mimeModes[spec];
      } else if (spec && typeof spec.name == "string" && mimeModes.hasOwnProperty(spec.name)) {
        var found = mimeModes[spec.name];
        if (typeof found == "string") found = {name: found};
        spec = createObj(found, spec);
        spec.name = found.name;
      } else if (typeof spec == "string" && /^[\w\-]+\/[\w\-]+\+xml$/.test(spec)) {
        return CodeMirror.resolveMode("application/xml");
      }
      if (typeof spec == "string") return {name: spec};
      else return spec || {name: "null"};
    };
  
    // Given a mode spec (anything that resolveMode accepts), find and
    // initialize an actual mode object.
    CodeMirror.getMode = function(options, spec) {
      var spec = CodeMirror.resolveMode(spec);
      var mfactory = modes[spec.name];
      if (!mfactory) return CodeMirror.getMode(options, "text/plain");
      var modeObj = mfactory(options, spec);
      if (modeExtensions.hasOwnProperty(spec.name)) {
        var exts = modeExtensions[spec.name];
        for (var prop in exts) {
          if (!exts.hasOwnProperty(prop)) continue;
          if (modeObj.hasOwnProperty(prop)) modeObj["_" + prop] = modeObj[prop];
          modeObj[prop] = exts[prop];
        }
      }
      modeObj.name = spec.name;
      if (spec.helperType) modeObj.helperType = spec.helperType;
      if (spec.modeProps) for (var prop in spec.modeProps)
        modeObj[prop] = spec.modeProps[prop];
  
      return modeObj;
    };
  
    // Minimal default mode.
    CodeMirror.defineMode("null", function() {
      return {token: function(stream) {stream.skipToEnd();}};
    });
    CodeMirror.defineMIME("text/plain", "null");
  
    // This can be used to attach properties to mode objects from
    // outside the actual mode definition.
    var modeExtensions = CodeMirror.modeExtensions = {};
    CodeMirror.extendMode = function(mode, properties) {
      var exts = modeExtensions.hasOwnProperty(mode) ? modeExtensions[mode] : (modeExtensions[mode] = {});
      copyObj(properties, exts);
    };
  
    // EXTENSIONS
  
    CodeMirror.defineExtension = function(name, func) {
      CodeMirror.prototype[name] = func;
    };
    CodeMirror.defineDocExtension = function(name, func) {
      Doc.prototype[name] = func;
    };
    CodeMirror.defineOption = option;
  
    var initHooks = [];
    CodeMirror.defineInitHook = function(f) {initHooks.push(f);};
  
    var helpers = CodeMirror.helpers = {};
    CodeMirror.registerHelper = function(type, name, value) {
      if (!helpers.hasOwnProperty(type)) helpers[type] = CodeMirror[type] = {_global: []};
      helpers[type][name] = value;
    };
    CodeMirror.registerGlobalHelper = function(type, name, predicate, value) {
      CodeMirror.registerHelper(type, name, value);
      helpers[type]._global.push({pred: predicate, val: value});
    };
  
    // MODE STATE HANDLING
  
    // Utility functions for working with state. Exported because nested
    // modes need to do this for their inner modes.
  
    var copyState = CodeMirror.copyState = function(mode, state) {
      if (state === true) return state;
      if (mode.copyState) return mode.copyState(state);
      var nstate = {};
      for (var n in state) {
        var val = state[n];
        if (val instanceof Array) val = val.concat([]);
        nstate[n] = val;
      }
      return nstate;
    };
  
    var startState = CodeMirror.startState = function(mode, a1, a2) {
      return mode.startState ? mode.startState(a1, a2) : true;
    };
  
    // Given a mode and a state (for that mode), find the inner mode and
    // state at the position that the state refers to.
    CodeMirror.innerMode = function(mode, state) {
      while (mode.innerMode) {
        var info = mode.innerMode(state);
        if (!info || info.mode == mode) break;
        state = info.state;
        mode = info.mode;
      }
      return info || {mode: mode, state: state};
    };
  
    // STANDARD COMMANDS
  
    // Commands are parameter-less actions that can be performed on an
    // editor, mostly used for keybindings.
    var commands = CodeMirror.commands = {
      selectAll: function(cm) {cm.setSelection(Pos(cm.firstLine(), 0), Pos(cm.lastLine()), sel_dontScroll);},
      singleSelection: function(cm) {
        cm.setSelection(cm.getCursor("anchor"), cm.getCursor("head"), sel_dontScroll);
      },
      killLine: function(cm) {
        deleteNearSelection(cm, function(range) {
          if (range.empty()) {
            var len = getLine(cm.doc, range.head.line).text.length;
            if (range.head.ch == len && range.head.line < cm.lastLine())
              return {from: range.head, to: Pos(range.head.line + 1, 0)};
            else
              return {from: range.head, to: Pos(range.head.line, len)};
          } else {
            return {from: range.from(), to: range.to()};
          }
        });
      },
      deleteLine: function(cm) {
        deleteNearSelection(cm, function(range) {
          return {from: Pos(range.from().line, 0),
                  to: clipPos(cm.doc, Pos(range.to().line + 1, 0))};
        });
      },
      delLineLeft: function(cm) {
        deleteNearSelection(cm, function(range) {
          return {from: Pos(range.from().line, 0), to: range.from()};
        });
      },
      delWrappedLineLeft: function(cm) {
        deleteNearSelection(cm, function(range) {
          var top = cm.charCoords(range.head, "div").top + 5;
          var leftPos = cm.coordsChar({left: 0, top: top}, "div");
          return {from: leftPos, to: range.from()};
        });
      },
      delWrappedLineRight: function(cm) {
        deleteNearSelection(cm, function(range) {
          var top = cm.charCoords(range.head, "div").top + 5;
          var rightPos = cm.coordsChar({left: cm.display.lineDiv.offsetWidth + 100, top: top}, "div");
          return {from: range.from(), to: rightPos };
        });
      },
      undo: function(cm) {cm.undo();},
      redo: function(cm) {cm.redo();},
      undoSelection: function(cm) {cm.undoSelection();},
      redoSelection: function(cm) {cm.redoSelection();},
      goDocStart: function(cm) {cm.extendSelection(Pos(cm.firstLine(), 0));},
      goDocEnd: function(cm) {cm.extendSelection(Pos(cm.lastLine()));},
      goLineStart: function(cm) {
        cm.extendSelectionsBy(function(range) { return lineStart(cm, range.head.line); },
                              {origin: "+move", bias: 1});
      },
      goLineStartSmart: function(cm) {
        cm.extendSelectionsBy(function(range) {
          return lineStartSmart(cm, range.head);
        }, {origin: "+move", bias: 1});
      },
      goLineEnd: function(cm) {
        cm.extendSelectionsBy(function(range) { return lineEnd(cm, range.head.line); },
                              {origin: "+move", bias: -1});
      },
      goLineRight: function(cm) {
        cm.extendSelectionsBy(function(range) {
          var top = cm.charCoords(range.head, "div").top + 5;
          return cm.coordsChar({left: cm.display.lineDiv.offsetWidth + 100, top: top}, "div");
        }, sel_move);
      },
      goLineLeft: function(cm) {
        cm.extendSelectionsBy(function(range) {
          var top = cm.charCoords(range.head, "div").top + 5;
          return cm.coordsChar({left: 0, top: top}, "div");
        }, sel_move);
      },
      goLineLeftSmart: function(cm) {
        cm.extendSelectionsBy(function(range) {
          var top = cm.charCoords(range.head, "div").top + 5;
          var pos = cm.coordsChar({left: 0, top: top}, "div");
          if (pos.ch < cm.getLine(pos.line).search(/\S/)) return lineStartSmart(cm, range.head);
          return pos;
        }, sel_move);
      },
      goLineUp: function(cm) {cm.moveV(-1, "line");},
      goLineDown: function(cm) {cm.moveV(1, "line");},
      goPageUp: function(cm) {cm.moveV(-1, "page");},
      goPageDown: function(cm) {cm.moveV(1, "page");},
      goCharLeft: function(cm) {cm.moveH(-1, "char");},
      goCharRight: function(cm) {cm.moveH(1, "char");},
      goColumnLeft: function(cm) {cm.moveH(-1, "column");},
      goColumnRight: function(cm) {cm.moveH(1, "column");},
      goWordLeft: function(cm) {cm.moveH(-1, "word");},
      goGroupRight: function(cm) {cm.moveH(1, "group");},
      goGroupLeft: function(cm) {cm.moveH(-1, "group");},
      goWordRight: function(cm) {cm.moveH(1, "word");},
      delCharBefore: function(cm) {cm.deleteH(-1, "char");},
      delCharAfter: function(cm) {cm.deleteH(1, "char");},
      delWordBefore: function(cm) {cm.deleteH(-1, "word");},
      delWordAfter: function(cm) {cm.deleteH(1, "word");},
      delGroupBefore: function(cm) {cm.deleteH(-1, "group");},
      delGroupAfter: function(cm) {cm.deleteH(1, "group");},
      indentAuto: function(cm) {cm.indentSelection("smart");},
      indentMore: function(cm) {cm.indentSelection("add");},
      indentLess: function(cm) {cm.indentSelection("subtract");},
      insertTab: function(cm) {cm.replaceSelection("\t");},
      insertSoftTab: function(cm) {
        var spaces = [], ranges = cm.listSelections(), tabSize = cm.options.tabSize;
        for (var i = 0; i < ranges.length; i++) {
          var pos = ranges[i].from();
          var col = countColumn(cm.getLine(pos.line), pos.ch, tabSize);
          spaces.push(new Array(tabSize - col % tabSize + 1).join(" "));
        }
        cm.replaceSelections(spaces);
      },
      defaultTab: function(cm) {
        if (cm.somethingSelected()) cm.indentSelection("add");
        else cm.execCommand("insertTab");
      },
      transposeChars: function(cm) {
        runInOp(cm, function() {
          var ranges = cm.listSelections(), newSel = [];
          for (var i = 0; i < ranges.length; i++) {
            var cur = ranges[i].head, line = getLine(cm.doc, cur.line).text;
            if (line) {
              if (cur.ch == line.length) cur = new Pos(cur.line, cur.ch - 1);
              if (cur.ch > 0) {
                cur = new Pos(cur.line, cur.ch + 1);
                cm.replaceRange(line.charAt(cur.ch - 1) + line.charAt(cur.ch - 2),
                                Pos(cur.line, cur.ch - 2), cur, "+transpose");
              } else if (cur.line > cm.doc.first) {
                var prev = getLine(cm.doc, cur.line - 1).text;
                if (prev)
                  cm.replaceRange(line.charAt(0) + cm.doc.lineSeparator() +
                                  prev.charAt(prev.length - 1),
                                  Pos(cur.line - 1, prev.length - 1), Pos(cur.line, 1), "+transpose");
              }
            }
            newSel.push(new Range(cur, cur));
          }
          cm.setSelections(newSel);
        });
      },
      newlineAndIndent: function(cm) {
        runInOp(cm, function() {
          var len = cm.listSelections().length;
          for (var i = 0; i < len; i++) {
            var range = cm.listSelections()[i];
            cm.replaceRange(cm.doc.lineSeparator(), range.anchor, range.head, "+input");
            cm.indentLine(range.from().line + 1, null, true);
          }
          ensureCursorVisible(cm);
        });
      },
      toggleOverwrite: function(cm) {cm.toggleOverwrite();}
    };
  
  
    // STANDARD KEYMAPS
  
    var keyMap = CodeMirror.keyMap = {};
  
    keyMap.basic = {
      "Left": "goCharLeft", "Right": "goCharRight", "Up": "goLineUp", "Down": "goLineDown",
      "End": "goLineEnd", "Home": "goLineStartSmart", "PageUp": "goPageUp", "PageDown": "goPageDown",
      "Delete": "delCharAfter", "Backspace": "delCharBefore", "Shift-Backspace": "delCharBefore",
      "Tab": "defaultTab", "Shift-Tab": "indentAuto",
      "Enter": "newlineAndIndent", "Insert": "toggleOverwrite",
      "Esc": "singleSelection"
    };
    // Note that the save and find-related commands aren't defined by
    // default. User code or addons can define them. Unknown commands
    // are simply ignored.
    keyMap.pcDefault = {
      "Ctrl-A": "selectAll", "Ctrl-D": "deleteLine", "Ctrl-Z": "undo", "Shift-Ctrl-Z": "redo", "Ctrl-Y": "redo",
      "Ctrl-Home": "goDocStart", "Ctrl-End": "goDocEnd", "Ctrl-Up": "goLineUp", "Ctrl-Down": "goLineDown",
      "Ctrl-Left": "goGroupLeft", "Ctrl-Right": "goGroupRight", "Alt-Left": "goLineStart", "Alt-Right": "goLineEnd",
      "Ctrl-Backspace": "delGroupBefore", "Ctrl-Delete": "delGroupAfter", "Ctrl-S": "save", "Ctrl-F": "find",
      "Ctrl-G": "findNext", "Shift-Ctrl-G": "findPrev", "Shift-Ctrl-F": "replace", "Shift-Ctrl-R": "replaceAll",
      "Ctrl-[": "indentLess", "Ctrl-]": "indentMore",
      "Ctrl-U": "undoSelection", "Shift-Ctrl-U": "redoSelection", "Alt-U": "redoSelection",
      fallthrough: "basic"
    };
    // Very basic readline/emacs-style bindings, which are standard on Mac.
    keyMap.emacsy = {
      "Ctrl-F": "goCharRight", "Ctrl-B": "goCharLeft", "Ctrl-P": "goLineUp", "Ctrl-N": "goLineDown",
      "Alt-F": "goWordRight", "Alt-B": "goWordLeft", "Ctrl-A": "goLineStart", "Ctrl-E": "goLineEnd",
      "Ctrl-V": "goPageDown", "Shift-Ctrl-V": "goPageUp", "Ctrl-D": "delCharAfter", "Ctrl-H": "delCharBefore",
      "Alt-D": "delWordAfter", "Alt-Backspace": "delWordBefore", "Ctrl-K": "killLine", "Ctrl-T": "transposeChars"
    };
    keyMap.macDefault = {
      "Cmd-A": "selectAll", "Cmd-D": "deleteLine", "Cmd-Z": "undo", "Shift-Cmd-Z": "redo", "Cmd-Y": "redo",
      "Cmd-Home": "goDocStart", "Cmd-Up": "goDocStart", "Cmd-End": "goDocEnd", "Cmd-Down": "goDocEnd", "Alt-Left": "goGroupLeft",
      "Alt-Right": "goGroupRight", "Cmd-Left": "goLineLeft", "Cmd-Right": "goLineRight", "Alt-Backspace": "delGroupBefore",
      "Ctrl-Alt-Backspace": "delGroupAfter", "Alt-Delete": "delGroupAfter", "Cmd-S": "save", "Cmd-F": "find",
      "Cmd-G": "findNext", "Shift-Cmd-G": "findPrev", "Cmd-Alt-F": "replace", "Shift-Cmd-Alt-F": "replaceAll",
      "Cmd-[": "indentLess", "Cmd-]": "indentMore", "Cmd-Backspace": "delWrappedLineLeft", "Cmd-Delete": "delWrappedLineRight",
      "Cmd-U": "undoSelection", "Shift-Cmd-U": "redoSelection", "Ctrl-Up": "goDocStart", "Ctrl-Down": "goDocEnd",
      fallthrough: ["basic", "emacsy"]
    };
    keyMap["default"] = mac ? keyMap.macDefault : keyMap.pcDefault;
  
    // KEYMAP DISPATCH
  
    function normalizeKeyName(name) {
      var parts = name.split(/-(?!$)/), name = parts[parts.length - 1];
      var alt, ctrl, shift, cmd;
      for (var i = 0; i < parts.length - 1; i++) {
        var mod = parts[i];
        if (/^(cmd|meta|m)$/i.test(mod)) cmd = true;
        else if (/^a(lt)?$/i.test(mod)) alt = true;
        else if (/^(c|ctrl|control)$/i.test(mod)) ctrl = true;
        else if (/^s(hift)$/i.test(mod)) shift = true;
        else throw new Error("Unrecognized modifier name: " + mod);
      }
      if (alt) name = "Alt-" + name;
      if (ctrl) name = "Ctrl-" + name;
      if (cmd) name = "Cmd-" + name;
      if (shift) name = "Shift-" + name;
      return name;
    }
  
    // This is a kludge to keep keymaps mostly working as raw objects
    // (backwards compatibility) while at the same time support features
    // like normalization and multi-stroke key bindings. It compiles a
    // new normalized keymap, and then updates the old object to reflect
    // this.
    CodeMirror.normalizeKeyMap = function(keymap) {
      var copy = {};
      for (var keyname in keymap) if (keymap.hasOwnProperty(keyname)) {
        var value = keymap[keyname];
        if (/^(name|fallthrough|(de|at)tach)$/.test(keyname)) continue;
        if (value == "...") { delete keymap[keyname]; continue; }
  
        var keys = map(keyname.split(" "), normalizeKeyName);
        for (var i = 0; i < keys.length; i++) {
          var val, name;
          if (i == keys.length - 1) {
            name = keys.join(" ");
            val = value;
          } else {
            name = keys.slice(0, i + 1).join(" ");
            val = "...";
          }
          var prev = copy[name];
          if (!prev) copy[name] = val;
          else if (prev != val) throw new Error("Inconsistent bindings for " + name);
        }
        delete keymap[keyname];
      }
      for (var prop in copy) keymap[prop] = copy[prop];
      return keymap;
    };
  
    var lookupKey = CodeMirror.lookupKey = function(key, map, handle, context) {
      map = getKeyMap(map);
      var found = map.call ? map.call(key, context) : map[key];
      if (found === false) return "nothing";
      if (found === "...") return "multi";
      if (found != null && handle(found)) return "handled";
  
      if (map.fallthrough) {
        if (Object.prototype.toString.call(map.fallthrough) != "[object Array]")
          return lookupKey(key, map.fallthrough, handle, context);
        for (var i = 0; i < map.fallthrough.length; i++) {
          var result = lookupKey(key, map.fallthrough[i], handle, context);
          if (result) return result;
        }
      }
    };
  
    // Modifier key presses don't count as 'real' key presses for the
    // purpose of keymap fallthrough.
    var isModifierKey = CodeMirror.isModifierKey = function(value) {
      var name = typeof value == "string" ? value : keyNames[value.keyCode];
      return name == "Ctrl" || name == "Alt" || name == "Shift" || name == "Mod";
    };
  
    // Look up the name of a key as indicated by an event object.
    var keyName = CodeMirror.keyName = function(event, noShift) {
      if (presto && event.keyCode == 34 && event["char"]) return false;
      var base = keyNames[event.keyCode], name = base;
      if (name == null || event.altGraphKey) return false;
      if (event.altKey && base != "Alt") name = "Alt-" + name;
      if ((flipCtrlCmd ? event.metaKey : event.ctrlKey) && base != "Ctrl") name = "Ctrl-" + name;
      if ((flipCtrlCmd ? event.ctrlKey : event.metaKey) && base != "Cmd") name = "Cmd-" + name;
      if (!noShift && event.shiftKey && base != "Shift") name = "Shift-" + name;
      return name;
    };
  
    function getKeyMap(val) {
      return typeof val == "string" ? keyMap[val] : val;
    }
  
    // FROMTEXTAREA
  
    CodeMirror.fromTextArea = function(textarea, options) {
      options = options ? copyObj(options) : {};
      options.value = textarea.value;
      if (!options.tabindex && textarea.tabIndex)
        options.tabindex = textarea.tabIndex;
      if (!options.placeholder && textarea.placeholder)
        options.placeholder = textarea.placeholder;
      // Set autofocus to true if this textarea is focused, or if it has
      // autofocus and no other element is focused.
      if (options.autofocus == null) {
        var hasFocus = activeElt();
        options.autofocus = hasFocus == textarea ||
          textarea.getAttribute("autofocus") != null && hasFocus == document.body;
      }
  
      function save() {textarea.value = cm.getValue();}
      if (textarea.form) {
        on(textarea.form, "submit", save);
        // Deplorable hack to make the submit method do the right thing.
        if (!options.leaveSubmitMethodAlone) {
          var form = textarea.form, realSubmit = form.submit;
          try {
            var wrappedSubmit = form.submit = function() {
              save();
              form.submit = realSubmit;
              form.submit();
              form.submit = wrappedSubmit;
            };
          } catch(e) {}
        }
      }
  
      options.finishInit = function(cm) {
        cm.save = save;
        cm.getTextArea = function() { return textarea; };
        cm.toTextArea = function() {
          cm.toTextArea = isNaN; // Prevent this from being ran twice
          save();
          textarea.parentNode.removeChild(cm.getWrapperElement());
          textarea.style.display = "";
          if (textarea.form) {
            off(textarea.form, "submit", save);
            if (typeof textarea.form.submit == "function")
              textarea.form.submit = realSubmit;
          }
        };
      };
  
      textarea.style.display = "none";
      var cm = CodeMirror(function(node) {
        textarea.parentNode.insertBefore(node, textarea.nextSibling);
      }, options);
      return cm;
    };
  
    // STRING STREAM
  
    // Fed to the mode parsers, provides helper functions to make
    // parsers more succinct.
  
    var StringStream = CodeMirror.StringStream = function(string, tabSize) {
      this.pos = this.start = 0;
      this.string = string;
      this.tabSize = tabSize || 8;
      this.lastColumnPos = this.lastColumnValue = 0;
      this.lineStart = 0;
    };
  
    StringStream.prototype = {
      eol: function() {return this.pos >= this.string.length;},
      sol: function() {return this.pos == this.lineStart;},
      peek: function() {return this.string.charAt(this.pos) || undefined;},
      next: function() {
        if (this.pos < this.string.length)
          return this.string.charAt(this.pos++);
      },
      eat: function(match) {
        var ch = this.string.charAt(this.pos);
        if (typeof match == "string") var ok = ch == match;
        else var ok = ch && (match.test ? match.test(ch) : match(ch));
        if (ok) {++this.pos; return ch;}
      },
      eatWhile: function(match) {
        var start = this.pos;
        while (this.eat(match)){}
        return this.pos > start;
      },
      eatSpace: function() {
        var start = this.pos;
        while (/[\s\u00a0]/.test(this.string.charAt(this.pos))) ++this.pos;
        return this.pos > start;
      },
      skipToEnd: function() {this.pos = this.string.length;},
      skipTo: function(ch) {
        var found = this.string.indexOf(ch, this.pos);
        if (found > -1) {this.pos = found; return true;}
      },
      backUp: function(n) {this.pos -= n;},
      column: function() {
        if (this.lastColumnPos < this.start) {
          this.lastColumnValue = countColumn(this.string, this.start, this.tabSize, this.lastColumnPos, this.lastColumnValue);
          this.lastColumnPos = this.start;
        }
        return this.lastColumnValue - (this.lineStart ? countColumn(this.string, this.lineStart, this.tabSize) : 0);
      },
      indentation: function() {
        return countColumn(this.string, null, this.tabSize) -
          (this.lineStart ? countColumn(this.string, this.lineStart, this.tabSize) : 0);
      },
      match: function(pattern, consume, caseInsensitive) {
        if (typeof pattern == "string") {
          var cased = function(str) {return caseInsensitive ? str.toLowerCase() : str;};
          var substr = this.string.substr(this.pos, pattern.length);
          if (cased(substr) == cased(pattern)) {
            if (consume !== false) this.pos += pattern.length;
            return true;
          }
        } else {
          var match = this.string.slice(this.pos).match(pattern);
          if (match && match.index > 0) return null;
          if (match && consume !== false) this.pos += match[0].length;
          return match;
        }
      },
      current: function(){return this.string.slice(this.start, this.pos);},
      hideFirstChars: function(n, inner) {
        this.lineStart += n;
        try { return inner(); }
        finally { this.lineStart -= n; }
      }
    };
  
    // TEXTMARKERS
  
    // Created with markText and setBookmark methods. A TextMarker is a
    // handle that can be used to clear or find a marked position in the
    // document. Line objects hold arrays (markedSpans) containing
    // {from, to, marker} object pointing to such marker objects, and
    // indicating that such a marker is present on that line. Multiple
    // lines may point to the same marker when it spans across lines.
    // The spans will have null for their from/to properties when the
    // marker continues beyond the start/end of the line. Markers have
    // links back to the lines they currently touch.
  
    var nextMarkerId = 0;
  
    var TextMarker = CodeMirror.TextMarker = function(doc, type) {
      this.lines = [];
      this.type = type;
      this.doc = doc;
      this.id = ++nextMarkerId;
    };
    eventMixin(TextMarker);
  
    // Clear the marker.
    TextMarker.prototype.clear = function() {
      if (this.explicitlyCleared) return;
      var cm = this.doc.cm, withOp = cm && !cm.curOp;
      if (withOp) startOperation(cm);
      if (hasHandler(this, "clear")) {
        var found = this.find();
        if (found) signalLater(this, "clear", found.from, found.to);
      }
      var min = null, max = null;
      for (var i = 0; i < this.lines.length; ++i) {
        var line = this.lines[i];
        var span = getMarkedSpanFor(line.markedSpans, this);
        if (cm && !this.collapsed) regLineChange(cm, lineNo(line), "text");
        else if (cm) {
          if (span.to != null) max = lineNo(line);
          if (span.from != null) min = lineNo(line);
        }
        line.markedSpans = removeMarkedSpan(line.markedSpans, span);
        if (span.from == null && this.collapsed && !lineIsHidden(this.doc, line) && cm)
          updateLineHeight(line, textHeight(cm.display));
      }
      if (cm && this.collapsed && !cm.options.lineWrapping) for (var i = 0; i < this.lines.length; ++i) {
        var visual = visualLine(this.lines[i]), len = lineLength(visual);
        if (len > cm.display.maxLineLength) {
          cm.display.maxLine = visual;
          cm.display.maxLineLength = len;
          cm.display.maxLineChanged = true;
        }
      }
  
      if (min != null && cm && this.collapsed) regChange(cm, min, max + 1);
      this.lines.length = 0;
      this.explicitlyCleared = true;
      if (this.atomic && this.doc.cantEdit) {
        this.doc.cantEdit = false;
        if (cm) reCheckSelection(cm.doc);
      }
      if (cm) signalLater(cm, "markerCleared", cm, this);
      if (withOp) endOperation(cm);
      if (this.parent) this.parent.clear();
    };
  
    // Find the position of the marker in the document. Returns a {from,
    // to} object by default. Side can be passed to get a specific side
    // -- 0 (both), -1 (left), or 1 (right). When lineObj is true, the
    // Pos objects returned contain a line object, rather than a line
    // number (used to prevent looking up the same line twice).
    TextMarker.prototype.find = function(side, lineObj) {
      if (side == null && this.type == "bookmark") side = 1;
      var from, to;
      for (var i = 0; i < this.lines.length; ++i) {
        var line = this.lines[i];
        var span = getMarkedSpanFor(line.markedSpans, this);
        if (span.from != null) {
          from = Pos(lineObj ? line : lineNo(line), span.from);
          if (side == -1) return from;
        }
        if (span.to != null) {
          to = Pos(lineObj ? line : lineNo(line), span.to);
          if (side == 1) return to;
        }
      }
      return from && {from: from, to: to};
    };
  
    // Signals that the marker's widget changed, and surrounding layout
    // should be recomputed.
    TextMarker.prototype.changed = function() {
      var pos = this.find(-1, true), widget = this, cm = this.doc.cm;
      if (!pos || !cm) return;
      runInOp(cm, function() {
        var line = pos.line, lineN = lineNo(pos.line);
        var view = findViewForLine(cm, lineN);
        if (view) {
          clearLineMeasurementCacheFor(view);
          cm.curOp.selectionChanged = cm.curOp.forceUpdate = true;
        }
        cm.curOp.updateMaxLine = true;
        if (!lineIsHidden(widget.doc, line) && widget.height != null) {
          var oldHeight = widget.height;
          widget.height = null;
          var dHeight = widgetHeight(widget) - oldHeight;
          if (dHeight)
            updateLineHeight(line, line.height + dHeight);
        }
      });
    };
  
    TextMarker.prototype.attachLine = function(line) {
      if (!this.lines.length && this.doc.cm) {
        var op = this.doc.cm.curOp;
        if (!op.maybeHiddenMarkers || indexOf(op.maybeHiddenMarkers, this) == -1)
          (op.maybeUnhiddenMarkers || (op.maybeUnhiddenMarkers = [])).push(this);
      }
      this.lines.push(line);
    };
    TextMarker.prototype.detachLine = function(line) {
      this.lines.splice(indexOf(this.lines, line), 1);
      if (!this.lines.length && this.doc.cm) {
        var op = this.doc.cm.curOp;
        (op.maybeHiddenMarkers || (op.maybeHiddenMarkers = [])).push(this);
      }
    };
  
    // Collapsed markers have unique ids, in order to be able to order
    // them, which is needed for uniquely determining an outer marker
    // when they overlap (they may nest, but not partially overlap).
    var nextMarkerId = 0;
  
    // Create a marker, wire it up to the right lines, and
    function markText(doc, from, to, options, type) {
      // Shared markers (across linked documents) are handled separately
      // (markTextShared will call out to this again, once per
      // document).
      if (options && options.shared) return markTextShared(doc, from, to, options, type);
      // Ensure we are in an operation.
      if (doc.cm && !doc.cm.curOp) return operation(doc.cm, markText)(doc, from, to, options, type);
  
      var marker = new TextMarker(doc, type), diff = cmp(from, to);
      if (options) copyObj(options, marker, false);
      // Don't connect empty markers unless clearWhenEmpty is false
      if (diff > 0 || diff == 0 && marker.clearWhenEmpty !== false)
        return marker;
      if (marker.replacedWith) {
        // Showing up as a widget implies collapsed (widget replaces text)
        marker.collapsed = true;
        marker.widgetNode = elt("span", [marker.replacedWith], "CodeMirror-widget");
        if (!options.handleMouseEvents) marker.widgetNode.setAttribute("cm-ignore-events", "true");
        if (options.insertLeft) marker.widgetNode.insertLeft = true;
      }
      if (marker.collapsed) {
        if (conflictingCollapsedRange(doc, from.line, from, to, marker) ||
            from.line != to.line && conflictingCollapsedRange(doc, to.line, from, to, marker))
          throw new Error("Inserting collapsed marker partially overlapping an existing one");
        sawCollapsedSpans = true;
      }
  
      if (marker.addToHistory)
        addChangeToHistory(doc, {from: from, to: to, origin: "markText"}, doc.sel, NaN);
  
      var curLine = from.line, cm = doc.cm, updateMaxLine;
      doc.iter(curLine, to.line + 1, function(line) {
        if (cm && marker.collapsed && !cm.options.lineWrapping && visualLine(line) == cm.display.maxLine)
          updateMaxLine = true;
        if (marker.collapsed && curLine != from.line) updateLineHeight(line, 0);
        addMarkedSpan(line, new MarkedSpan(marker,
                                           curLine == from.line ? from.ch : null,
                                           curLine == to.line ? to.ch : null));
        ++curLine;
      });
      // lineIsHidden depends on the presence of the spans, so needs a second pass
      if (marker.collapsed) doc.iter(from.line, to.line + 1, function(line) {
        if (lineIsHidden(doc, line)) updateLineHeight(line, 0);
      });
  
      if (marker.clearOnEnter) on(marker, "beforeCursorEnter", function() { marker.clear(); });
  
      if (marker.readOnly) {
        sawReadOnlySpans = true;
        if (doc.history.done.length || doc.history.undone.length)
          doc.clearHistory();
      }
      if (marker.collapsed) {
        marker.id = ++nextMarkerId;
        marker.atomic = true;
      }
      if (cm) {
        // Sync editor state
        if (updateMaxLine) cm.curOp.updateMaxLine = true;
        if (marker.collapsed)
          regChange(cm, from.line, to.line + 1);
        else if (marker.className || marker.title || marker.startStyle || marker.endStyle || marker.css)
          for (var i = from.line; i <= to.line; i++) regLineChange(cm, i, "text");
        if (marker.atomic) reCheckSelection(cm.doc);
        signalLater(cm, "markerAdded", cm, marker);
      }
      return marker;
    }
  
    // SHARED TEXTMARKERS
  
    // A shared marker spans multiple linked documents. It is
    // implemented as a meta-marker-object controlling multiple normal
    // markers.
    var SharedTextMarker = CodeMirror.SharedTextMarker = function(markers, primary) {
      this.markers = markers;
      this.primary = primary;
      for (var i = 0; i < markers.length; ++i)
        markers[i].parent = this;
    };
    eventMixin(SharedTextMarker);
  
    SharedTextMarker.prototype.clear = function() {
      if (this.explicitlyCleared) return;
      this.explicitlyCleared = true;
      for (var i = 0; i < this.markers.length; ++i)
        this.markers[i].clear();
      signalLater(this, "clear");
    };
    SharedTextMarker.prototype.find = function(side, lineObj) {
      return this.primary.find(side, lineObj);
    };
  
    function markTextShared(doc, from, to, options, type) {
      options = copyObj(options);
      options.shared = false;
      var markers = [markText(doc, from, to, options, type)], primary = markers[0];
      var widget = options.widgetNode;
      linkedDocs(doc, function(doc) {
        if (widget) options.widgetNode = widget.cloneNode(true);
        markers.push(markText(doc, clipPos(doc, from), clipPos(doc, to), options, type));
        for (var i = 0; i < doc.linked.length; ++i)
          if (doc.linked[i].isParent) return;
        primary = lst(markers);
      });
      return new SharedTextMarker(markers, primary);
    }
  
    function findSharedMarkers(doc) {
      return doc.findMarks(Pos(doc.first, 0), doc.clipPos(Pos(doc.lastLine())),
                           function(m) { return m.parent; });
    }
  
    function copySharedMarkers(doc, markers) {
      for (var i = 0; i < markers.length; i++) {
        var marker = markers[i], pos = marker.find();
        var mFrom = doc.clipPos(pos.from), mTo = doc.clipPos(pos.to);
        if (cmp(mFrom, mTo)) {
          var subMark = markText(doc, mFrom, mTo, marker.primary, marker.primary.type);
          marker.markers.push(subMark);
          subMark.parent = marker;
        }
      }
    }
  
    function detachSharedMarkers(markers) {
      for (var i = 0; i < markers.length; i++) {
        var marker = markers[i], linked = [marker.primary.doc];;
        linkedDocs(marker.primary.doc, function(d) { linked.push(d); });
        for (var j = 0; j < marker.markers.length; j++) {
          var subMarker = marker.markers[j];
          if (indexOf(linked, subMarker.doc) == -1) {
            subMarker.parent = null;
            marker.markers.splice(j--, 1);
          }
        }
      }
    }
  
    // TEXTMARKER SPANS
  
    function MarkedSpan(marker, from, to) {
      this.marker = marker;
      this.from = from; this.to = to;
    }
  
    // Search an array of spans for a span matching the given marker.
    function getMarkedSpanFor(spans, marker) {
      if (spans) for (var i = 0; i < spans.length; ++i) {
        var span = spans[i];
        if (span.marker == marker) return span;
      }
    }
    // Remove a span from an array, returning undefined if no spans are
    // left (we don't store arrays for lines without spans).
    function removeMarkedSpan(spans, span) {
      for (var r, i = 0; i < spans.length; ++i)
        if (spans[i] != span) (r || (r = [])).push(spans[i]);
      return r;
    }
    // Add a span to a line.
    function addMarkedSpan(line, span) {
      line.markedSpans = line.markedSpans ? line.markedSpans.concat([span]) : [span];
      span.marker.attachLine(line);
    }
  
    // Used for the algorithm that adjusts markers for a change in the
    // document. These functions cut an array of spans at a given
    // character position, returning an array of remaining chunks (or
    // undefined if nothing remains).
    function markedSpansBefore(old, startCh, isInsert) {
      if (old) for (var i = 0, nw; i < old.length; ++i) {
        var span = old[i], marker = span.marker;
        var startsBefore = span.from == null || (marker.inclusiveLeft ? span.from <= startCh : span.from < startCh);
        if (startsBefore || span.from == startCh && marker.type == "bookmark" && (!isInsert || !span.marker.insertLeft)) {
          var endsAfter = span.to == null || (marker.inclusiveRight ? span.to >= startCh : span.to > startCh);
          (nw || (nw = [])).push(new MarkedSpan(marker, span.from, endsAfter ? null : span.to));
        }
      }
      return nw;
    }
    function markedSpansAfter(old, endCh, isInsert) {
      if (old) for (var i = 0, nw; i < old.length; ++i) {
        var span = old[i], marker = span.marker;
        var endsAfter = span.to == null || (marker.inclusiveRight ? span.to >= endCh : span.to > endCh);
        if (endsAfter || span.from == endCh && marker.type == "bookmark" && (!isInsert || span.marker.insertLeft)) {
          var startsBefore = span.from == null || (marker.inclusiveLeft ? span.from <= endCh : span.from < endCh);
          (nw || (nw = [])).push(new MarkedSpan(marker, startsBefore ? null : span.from - endCh,
                                                span.to == null ? null : span.to - endCh));
        }
      }
      return nw;
    }
  
    // Given a change object, compute the new set of marker spans that
    // cover the line in which the change took place. Removes spans
    // entirely within the change, reconnects spans belonging to the
    // same marker that appear on both sides of the change, and cuts off
    // spans partially within the change. Returns an array of span
    // arrays with one element for each line in (after) the change.
    function stretchSpansOverChange(doc, change) {
      if (change.full) return null;
      var oldFirst = isLine(doc, change.from.line) && getLine(doc, change.from.line).markedSpans;
      var oldLast = isLine(doc, change.to.line) && getLine(doc, change.to.line).markedSpans;
      if (!oldFirst && !oldLast) return null;
  
      var startCh = change.from.ch, endCh = change.to.ch, isInsert = cmp(change.from, change.to) == 0;
      // Get the spans that 'stick out' on both sides
      var first = markedSpansBefore(oldFirst, startCh, isInsert);
      var last = markedSpansAfter(oldLast, endCh, isInsert);
  
      // Next, merge those two ends
      var sameLine = change.text.length == 1, offset = lst(change.text).length + (sameLine ? startCh : 0);
      if (first) {
        // Fix up .to properties of first
        for (var i = 0; i < first.length; ++i) {
          var span = first[i];
          if (span.to == null) {
            var found = getMarkedSpanFor(last, span.marker);
            if (!found) span.to = startCh;
            else if (sameLine) span.to = found.to == null ? null : found.to + offset;
          }
        }
      }
      if (last) {
        // Fix up .from in last (or move them into first in case of sameLine)
        for (var i = 0; i < last.length; ++i) {
          var span = last[i];
          if (span.to != null) span.to += offset;
          if (span.from == null) {
            var found = getMarkedSpanFor(first, span.marker);
            if (!found) {
              span.from = offset;
              if (sameLine) (first || (first = [])).push(span);
            }
          } else {
            span.from += offset;
            if (sameLine) (first || (first = [])).push(span);
          }
        }
      }
      // Make sure we didn't create any zero-length spans
      if (first) first = clearEmptySpans(first);
      if (last && last != first) last = clearEmptySpans(last);
  
      var newMarkers = [first];
      if (!sameLine) {
        // Fill gap with whole-line-spans
        var gap = change.text.length - 2, gapMarkers;
        if (gap > 0 && first)
          for (var i = 0; i < first.length; ++i)
            if (first[i].to == null)
              (gapMarkers || (gapMarkers = [])).push(new MarkedSpan(first[i].marker, null, null));
        for (var i = 0; i < gap; ++i)
          newMarkers.push(gapMarkers);
        newMarkers.push(last);
      }
      return newMarkers;
    }
  
    // Remove spans that are empty and don't have a clearWhenEmpty
    // option of false.
    function clearEmptySpans(spans) {
      for (var i = 0; i < spans.length; ++i) {
        var span = spans[i];
        if (span.from != null && span.from == span.to && span.marker.clearWhenEmpty !== false)
          spans.splice(i--, 1);
      }
      if (!spans.length) return null;
      return spans;
    }
  
    // Used for un/re-doing changes from the history. Combines the
    // result of computing the existing spans with the set of spans that
    // existed in the history (so that deleting around a span and then
    // undoing brings back the span).
    function mergeOldSpans(doc, change) {
      var old = getOldSpans(doc, change);
      var stretched = stretchSpansOverChange(doc, change);
      if (!old) return stretched;
      if (!stretched) return old;
  
      for (var i = 0; i < old.length; ++i) {
        var oldCur = old[i], stretchCur = stretched[i];
        if (oldCur && stretchCur) {
          spans: for (var j = 0; j < stretchCur.length; ++j) {
            var span = stretchCur[j];
            for (var k = 0; k < oldCur.length; ++k)
              if (oldCur[k].marker == span.marker) continue spans;
            oldCur.push(span);
          }
        } else if (stretchCur) {
          old[i] = stretchCur;
        }
      }
      return old;
    }
  
    // Used to 'clip' out readOnly ranges when making a change.
    function removeReadOnlyRanges(doc, from, to) {
      var markers = null;
      doc.iter(from.line, to.line + 1, function(line) {
        if (line.markedSpans) for (var i = 0; i < line.markedSpans.length; ++i) {
          var mark = line.markedSpans[i].marker;
          if (mark.readOnly && (!markers || indexOf(markers, mark) == -1))
            (markers || (markers = [])).push(mark);
        }
      });
      if (!markers) return null;
      var parts = [{from: from, to: to}];
      for (var i = 0; i < markers.length; ++i) {
        var mk = markers[i], m = mk.find(0);
        for (var j = 0; j < parts.length; ++j) {
          var p = parts[j];
          if (cmp(p.to, m.from) < 0 || cmp(p.from, m.to) > 0) continue;
          var newParts = [j, 1], dfrom = cmp(p.from, m.from), dto = cmp(p.to, m.to);
          if (dfrom < 0 || !mk.inclusiveLeft && !dfrom)
            newParts.push({from: p.from, to: m.from});
          if (dto > 0 || !mk.inclusiveRight && !dto)
            newParts.push({from: m.to, to: p.to});
          parts.splice.apply(parts, newParts);
          j += newParts.length - 1;
        }
      }
      return parts;
    }
  
    // Connect or disconnect spans from a line.
    function detachMarkedSpans(line) {
      var spans = line.markedSpans;
      if (!spans) return;
      for (var i = 0; i < spans.length; ++i)
        spans[i].marker.detachLine(line);
      line.markedSpans = null;
    }
    function attachMarkedSpans(line, spans) {
      if (!spans) return;
      for (var i = 0; i < spans.length; ++i)
        spans[i].marker.attachLine(line);
      line.markedSpans = spans;
    }
  
    // Helpers used when computing which overlapping collapsed span
    // counts as the larger one.
    function extraLeft(marker) { return marker.inclusiveLeft ? -1 : 0; }
    function extraRight(marker) { return marker.inclusiveRight ? 1 : 0; }
  
    // Returns a number indicating which of two overlapping collapsed
    // spans is larger (and thus includes the other). Falls back to
    // comparing ids when the spans cover exactly the same range.
    function compareCollapsedMarkers(a, b) {
      var lenDiff = a.lines.length - b.lines.length;
      if (lenDiff != 0) return lenDiff;
      var aPos = a.find(), bPos = b.find();
      var fromCmp = cmp(aPos.from, bPos.from) || extraLeft(a) - extraLeft(b);
      if (fromCmp) return -fromCmp;
      var toCmp = cmp(aPos.to, bPos.to) || extraRight(a) - extraRight(b);
      if (toCmp) return toCmp;
      return b.id - a.id;
    }
  
    // Find out whether a line ends or starts in a collapsed span. If
    // so, return the marker for that span.
    function collapsedSpanAtSide(line, start) {
      var sps = sawCollapsedSpans && line.markedSpans, found;
      if (sps) for (var sp, i = 0; i < sps.length; ++i) {
        sp = sps[i];
        if (sp.marker.collapsed && (start ? sp.from : sp.to) == null &&
            (!found || compareCollapsedMarkers(found, sp.marker) < 0))
          found = sp.marker;
      }
      return found;
    }
    function collapsedSpanAtStart(line) { return collapsedSpanAtSide(line, true); }
    function collapsedSpanAtEnd(line) { return collapsedSpanAtSide(line, false); }
  
    // Test whether there exists a collapsed span that partially
    // overlaps (covers the start or end, but not both) of a new span.
    // Such overlap is not allowed.
    function conflictingCollapsedRange(doc, lineNo, from, to, marker) {
      var line = getLine(doc, lineNo);
      var sps = sawCollapsedSpans && line.markedSpans;
      if (sps) for (var i = 0; i < sps.length; ++i) {
        var sp = sps[i];
        if (!sp.marker.collapsed) continue;
        var found = sp.marker.find(0);
        var fromCmp = cmp(found.from, from) || extraLeft(sp.marker) - extraLeft(marker);
        var toCmp = cmp(found.to, to) || extraRight(sp.marker) - extraRight(marker);
        if (fromCmp >= 0 && toCmp <= 0 || fromCmp <= 0 && toCmp >= 0) continue;
        if (fromCmp <= 0 && (cmp(found.to, from) > 0 || (sp.marker.inclusiveRight && marker.inclusiveLeft)) ||
            fromCmp >= 0 && (cmp(found.from, to) < 0 || (sp.marker.inclusiveLeft && marker.inclusiveRight)))
          return true;
      }
    }
  
    // A visual line is a line as drawn on the screen. Folding, for
    // example, can cause multiple logical lines to appear on the same
    // visual line. This finds the start of the visual line that the
    // given line is part of (usually that is the line itself).
    function visualLine(line) {
      var merged;
      while (merged = collapsedSpanAtStart(line))
        line = merged.find(-1, true).line;
      return line;
    }
  
    // Returns an array of logical lines that continue the visual line
    // started by the argument, or undefined if there are no such lines.
    function visualLineContinued(line) {
      var merged, lines;
      while (merged = collapsedSpanAtEnd(line)) {
        line = merged.find(1, true).line;
        (lines || (lines = [])).push(line);
      }
      return lines;
    }
  
    // Get the line number of the start of the visual line that the
    // given line number is part of.
    function visualLineNo(doc, lineN) {
      var line = getLine(doc, lineN), vis = visualLine(line);
      if (line == vis) return lineN;
      return lineNo(vis);
    }
    // Get the line number of the start of the next visual line after
    // the given line.
    function visualLineEndNo(doc, lineN) {
      if (lineN > doc.lastLine()) return lineN;
      var line = getLine(doc, lineN), merged;
      if (!lineIsHidden(doc, line)) return lineN;
      while (merged = collapsedSpanAtEnd(line))
        line = merged.find(1, true).line;
      return lineNo(line) + 1;
    }
  
    // Compute whether a line is hidden. Lines count as hidden when they
    // are part of a visual line that starts with another line, or when
    // they are entirely covered by collapsed, non-widget span.
    function lineIsHidden(doc, line) {
      var sps = sawCollapsedSpans && line.markedSpans;
      if (sps) for (var sp, i = 0; i < sps.length; ++i) {
        sp = sps[i];
        if (!sp.marker.collapsed) continue;
        if (sp.from == null) return true;
        if (sp.marker.widgetNode) continue;
        if (sp.from == 0 && sp.marker.inclusiveLeft && lineIsHiddenInner(doc, line, sp))
          return true;
      }
    }
    function lineIsHiddenInner(doc, line, span) {
      if (span.to == null) {
        var end = span.marker.find(1, true);
        return lineIsHiddenInner(doc, end.line, getMarkedSpanFor(end.line.markedSpans, span.marker));
      }
      if (span.marker.inclusiveRight && span.to == line.text.length)
        return true;
      for (var sp, i = 0; i < line.markedSpans.length; ++i) {
        sp = line.markedSpans[i];
        if (sp.marker.collapsed && !sp.marker.widgetNode && sp.from == span.to &&
            (sp.to == null || sp.to != span.from) &&
            (sp.marker.inclusiveLeft || span.marker.inclusiveRight) &&
            lineIsHiddenInner(doc, line, sp)) return true;
      }
    }
  
    // LINE WIDGETS
  
    // Line widgets are block elements displayed above or below a line.
  
    var LineWidget = CodeMirror.LineWidget = function(doc, node, options) {
      if (options) for (var opt in options) if (options.hasOwnProperty(opt))
        this[opt] = options[opt];
      this.doc = doc;
      this.node = node;
    };
    eventMixin(LineWidget);
  
    function adjustScrollWhenAboveVisible(cm, line, diff) {
      if (heightAtLine(line) < ((cm.curOp && cm.curOp.scrollTop) || cm.doc.scrollTop))
        addToScrollPos(cm, null, diff);
    }
  
    LineWidget.prototype.clear = function() {
      var cm = this.doc.cm, ws = this.line.widgets, line = this.line, no = lineNo(line);
      if (no == null || !ws) return;
      for (var i = 0; i < ws.length; ++i) if (ws[i] == this) ws.splice(i--, 1);
      if (!ws.length) line.widgets = null;
      var height = widgetHeight(this);
      updateLineHeight(line, Math.max(0, line.height - height));
      if (cm) runInOp(cm, function() {
        adjustScrollWhenAboveVisible(cm, line, -height);
        regLineChange(cm, no, "widget");
      });
    };
    LineWidget.prototype.changed = function() {
      var oldH = this.height, cm = this.doc.cm, line = this.line;
      this.height = null;
      var diff = widgetHeight(this) - oldH;
      if (!diff) return;
      updateLineHeight(line, line.height + diff);
      if (cm) runInOp(cm, function() {
        cm.curOp.forceUpdate = true;
        adjustScrollWhenAboveVisible(cm, line, diff);
      });
    };
  
    function widgetHeight(widget) {
      if (widget.height != null) return widget.height;
      var cm = widget.doc.cm;
      if (!cm) return 0;
      if (!contains(document.body, widget.node)) {
        var parentStyle = "position: relative;";
        if (widget.coverGutter)
          parentStyle += "margin-left: -" + cm.display.gutters.offsetWidth + "px;";
        if (widget.noHScroll)
          parentStyle += "width: " + cm.display.wrapper.clientWidth + "px;";
        removeChildrenAndAdd(cm.display.measure, elt("div", [widget.node], null, parentStyle));
      }
      return widget.height = widget.node.parentNode.offsetHeight;
    }
  
    function addLineWidget(doc, handle, node, options) {
      var widget = new LineWidget(doc, node, options);
      var cm = doc.cm;
      if (cm && widget.noHScroll) cm.display.alignWidgets = true;
      changeLine(doc, handle, "widget", function(line) {
        var widgets = line.widgets || (line.widgets = []);
        if (widget.insertAt == null) widgets.push(widget);
        else widgets.splice(Math.min(widgets.length - 1, Math.max(0, widget.insertAt)), 0, widget);
        widget.line = line;
        if (cm && !lineIsHidden(doc, line)) {
          var aboveVisible = heightAtLine(line) < doc.scrollTop;
          updateLineHeight(line, line.height + widgetHeight(widget));
          if (aboveVisible) addToScrollPos(cm, null, widget.height);
          cm.curOp.forceUpdate = true;
        }
        return true;
      });
      return widget;
    }
  
    // LINE DATA STRUCTURE
  
    // Line objects. These hold state related to a line, including
    // highlighting info (the styles array).
    var Line = CodeMirror.Line = function(text, markedSpans, estimateHeight) {
      this.text = text;
      attachMarkedSpans(this, markedSpans);
      this.height = estimateHeight ? estimateHeight(this) : 1;
    };
    eventMixin(Line);
    Line.prototype.lineNo = function() { return lineNo(this); };
  
    // Change the content (text, markers) of a line. Automatically
    // invalidates cached information and tries to re-estimate the
    // line's height.
    function updateLine(line, text, markedSpans, estimateHeight) {
      line.text = text;
      if (line.stateAfter) line.stateAfter = null;
      if (line.styles) line.styles = null;
      if (line.order != null) line.order = null;
      detachMarkedSpans(line);
      attachMarkedSpans(line, markedSpans);
      var estHeight = estimateHeight ? estimateHeight(line) : 1;
      if (estHeight != line.height) updateLineHeight(line, estHeight);
    }
  
    // Detach a line from the document tree and its markers.
    function cleanUpLine(line) {
      line.parent = null;
      detachMarkedSpans(line);
    }
  
    function extractLineClasses(type, output) {
      if (type) for (;;) {
        var lineClass = type.match(/(?:^|\s+)line-(background-)?(\S+)/);
        if (!lineClass) break;
        type = type.slice(0, lineClass.index) + type.slice(lineClass.index + lineClass[0].length);
        var prop = lineClass[1] ? "bgClass" : "textClass";
        if (output[prop] == null)
          output[prop] = lineClass[2];
        else if (!(new RegExp("(?:^|\s)" + lineClass[2] + "(?:$|\s)")).test(output[prop]))
          output[prop] += " " + lineClass[2];
      }
      return type;
    }
  
    function callBlankLine(mode, state) {
      if (mode.blankLine) return mode.blankLine(state);
      if (!mode.innerMode) return;
      var inner = CodeMirror.innerMode(mode, state);
      if (inner.mode.blankLine) return inner.mode.blankLine(inner.state);
    }
  
    function readToken(mode, stream, state, inner) {
      for (var i = 0; i < 10; i++) {
        if (inner) inner[0] = CodeMirror.innerMode(mode, state).mode;
        var style = mode.token(stream, state);
        if (stream.pos > stream.start) return style;
      }
      throw new Error("Mode " + mode.name + " failed to advance stream.");
    }
  
    // Utility for getTokenAt and getLineTokens
    function takeToken(cm, pos, precise, asArray) {
      function getObj(copy) {
        return {start: stream.start, end: stream.pos,
                string: stream.current(),
                type: style || null,
                state: copy ? copyState(doc.mode, state) : state};
      }
  
      var doc = cm.doc, mode = doc.mode, style;
      pos = clipPos(doc, pos);
      var line = getLine(doc, pos.line), state = getStateBefore(cm, pos.line, precise);
      var stream = new StringStream(line.text, cm.options.tabSize), tokens;
      if (asArray) tokens = [];
      while ((asArray || stream.pos < pos.ch) && !stream.eol()) {
        stream.start = stream.pos;
        style = readToken(mode, stream, state);
        if (asArray) tokens.push(getObj(true));
      }
      return asArray ? tokens : getObj();
    }
  
    // Run the given mode's parser over a line, calling f for each token.
    function runMode(cm, text, mode, state, f, lineClasses, forceToEnd) {
      var flattenSpans = mode.flattenSpans;
      if (flattenSpans == null) flattenSpans = cm.options.flattenSpans;
      var curStart = 0, curStyle = null;
      var stream = new StringStream(text, cm.options.tabSize), style;
      var inner = cm.options.addModeClass && [null];
      if (text == "") extractLineClasses(callBlankLine(mode, state), lineClasses);
      while (!stream.eol()) {
        if (stream.pos > cm.options.maxHighlightLength) {
          flattenSpans = false;
          if (forceToEnd) processLine(cm, text, state, stream.pos);
          stream.pos = text.length;
          style = null;
        } else {
          style = extractLineClasses(readToken(mode, stream, state, inner), lineClasses);
        }
        if (inner) {
          var mName = inner[0].name;
          if (mName) style = "m-" + (style ? mName + " " + style : mName);
        }
        if (!flattenSpans || curStyle != style) {
          while (curStart < stream.start) {
            curStart = Math.min(stream.start, curStart + 50000);
            f(curStart, curStyle);
          }
          curStyle = style;
        }
        stream.start = stream.pos;
      }
      while (curStart < stream.pos) {
        // Webkit seems to refuse to render text nodes longer than 57444 characters
        var pos = Math.min(stream.pos, curStart + 50000);
        f(pos, curStyle);
        curStart = pos;
      }
    }
  
    // Compute a style array (an array starting with a mode generation
    // -- for invalidation -- followed by pairs of end positions and
    // style strings), which is used to highlight the tokens on the
    // line.
    function highlightLine(cm, line, state, forceToEnd) {
      // A styles array always starts with a number identifying the
      // mode/overlays that it is based on (for easy invalidation).
      var st = [cm.state.modeGen], lineClasses = {};
      // Compute the base array of styles
      runMode(cm, line.text, cm.doc.mode, state, function(end, style) {
        st.push(end, style);
      }, lineClasses, forceToEnd);
  
      // Run overlays, adjust style array.
      for (var o = 0; o < cm.state.overlays.length; ++o) {
        var overlay = cm.state.overlays[o], i = 1, at = 0;
        runMode(cm, line.text, overlay.mode, true, function(end, style) {
          var start = i;
          // Ensure there's a token end at the current position, and that i points at it
          while (at < end) {
            var i_end = st[i];
            if (i_end > end)
              st.splice(i, 1, end, st[i+1], i_end);
            i += 2;
            at = Math.min(end, i_end);
          }
          if (!style) return;
          if (overlay.opaque) {
            st.splice(start, i - start, end, "cm-overlay " + style);
            i = start + 2;
          } else {
            for (; start < i; start += 2) {
              var cur = st[start+1];
              st[start+1] = (cur ? cur + " " : "") + "cm-overlay " + style;
            }
          }
        }, lineClasses);
      }
  
      return {styles: st, classes: lineClasses.bgClass || lineClasses.textClass ? lineClasses : null};
    }
  
    function getLineStyles(cm, line, updateFrontier) {
      if (!line.styles || line.styles[0] != cm.state.modeGen) {
        var state = getStateBefore(cm, lineNo(line));
        var result = highlightLine(cm, line, line.text.length > cm.options.maxHighlightLength ? copyState(cm.doc.mode, state) : state);
        line.stateAfter = state;
        line.styles = result.styles;
        if (result.classes) line.styleClasses = result.classes;
        else if (line.styleClasses) line.styleClasses = null;
        if (updateFrontier === cm.doc.frontier) cm.doc.frontier++;
      }
      return line.styles;
    }
  
    // Lightweight form of highlight -- proceed over this line and
    // update state, but don't save a style array. Used for lines that
    // aren't currently visible.
    function processLine(cm, text, state, startAt) {
      var mode = cm.doc.mode;
      var stream = new StringStream(text, cm.options.tabSize);
      stream.start = stream.pos = startAt || 0;
      if (text == "") callBlankLine(mode, state);
      while (!stream.eol()) {
        readToken(mode, stream, state);
        stream.start = stream.pos;
      }
    }
  
    // Convert a style as returned by a mode (either null, or a string
    // containing one or more styles) to a CSS style. This is cached,
    // and also looks for line-wide styles.
    var styleToClassCache = {}, styleToClassCacheWithMode = {};
    function interpretTokenStyle(style, options) {
      if (!style || /^\s*$/.test(style)) return null;
      var cache = options.addModeClass ? styleToClassCacheWithMode : styleToClassCache;
      return cache[style] ||
        (cache[style] = style.replace(/\S+/g, "cm-$&"));
    }
  
    // Render the DOM representation of the text of a line. Also builds
    // up a 'line map', which points at the DOM nodes that represent
    // specific stretches of text, and is used by the measuring code.
    // The returned object contains the DOM node, this map, and
    // information about line-wide styles that were set by the mode.
    function buildLineContent(cm, lineView) {
      // The padding-right forces the element to have a 'border', which
      // is needed on Webkit to be able to get line-level bounding
      // rectangles for it (in measureChar).
      var content = elt("span", null, null, webkit ? "padding-right: .1px" : null);
      var builder = {pre: elt("pre", [content], "CodeMirror-line"), content: content,
                     col: 0, pos: 0, cm: cm,
                     splitSpaces: (ie || webkit) && cm.getOption("lineWrapping")};
      lineView.measure = {};
  
      // Iterate over the logical lines that make up this visual line.
      for (var i = 0; i <= (lineView.rest ? lineView.rest.length : 0); i++) {
        var line = i ? lineView.rest[i - 1] : lineView.line, order;
        builder.pos = 0;
        builder.addToken = buildToken;
        // Optionally wire in some hacks into the token-rendering
        // algorithm, to deal with browser quirks.
        if (hasBadBidiRects(cm.display.measure) && (order = getOrder(line)))
          builder.addToken = buildTokenBadBidi(builder.addToken, order);
        builder.map = [];
        var allowFrontierUpdate = lineView != cm.display.externalMeasured && lineNo(line);
        insertLineContent(line, builder, getLineStyles(cm, line, allowFrontierUpdate));
        if (line.styleClasses) {
          if (line.styleClasses.bgClass)
            builder.bgClass = joinClasses(line.styleClasses.bgClass, builder.bgClass || "");
          if (line.styleClasses.textClass)
            builder.textClass = joinClasses(line.styleClasses.textClass, builder.textClass || "");
        }
  
        // Ensure at least a single node is present, for measuring.
        if (builder.map.length == 0)
          builder.map.push(0, 0, builder.content.appendChild(zeroWidthElement(cm.display.measure)));
  
        // Store the map and a cache object for the current logical line
        if (i == 0) {
          lineView.measure.map = builder.map;
          lineView.measure.cache = {};
        } else {
          (lineView.measure.maps || (lineView.measure.maps = [])).push(builder.map);
          (lineView.measure.caches || (lineView.measure.caches = [])).push({});
        }
      }
  
      // See issue #2901
      if (webkit && /\bcm-tab\b/.test(builder.content.lastChild.className))
        builder.content.className = "cm-tab-wrap-hack";
  
      signal(cm, "renderLine", cm, lineView.line, builder.pre);
      if (builder.pre.className)
        builder.textClass = joinClasses(builder.pre.className, builder.textClass || "");
  
      return builder;
    }
  
    function defaultSpecialCharPlaceholder(ch) {
      var token = elt("span", "\u2022", "cm-invalidchar");
      token.title = "\\u" + ch.charCodeAt(0).toString(16);
      token.setAttribute("aria-label", token.title);
      return token;
    }
  
    // Build up the DOM representation for a single token, and add it to
    // the line map. Takes care to render special characters separately.
    function buildToken(builder, text, style, startStyle, endStyle, title, css) {
      if (!text) return;
      var displayText = builder.splitSpaces ? text.replace(/ {3,}/g, splitSpaces) : text;
      var special = builder.cm.state.specialChars, mustWrap = false;
      if (!special.test(text)) {
        builder.col += text.length;
        var content = document.createTextNode(displayText);
        builder.map.push(builder.pos, builder.pos + text.length, content);
        if (ie && ie_version < 9) mustWrap = true;
        builder.pos += text.length;
      } else {
        var content = document.createDocumentFragment(), pos = 0;
        while (true) {
          special.lastIndex = pos;
          var m = special.exec(text);
          var skipped = m ? m.index - pos : text.length - pos;
          if (skipped) {
            var txt = document.createTextNode(displayText.slice(pos, pos + skipped));
            if (ie && ie_version < 9) content.appendChild(elt("span", [txt]));
            else content.appendChild(txt);
            builder.map.push(builder.pos, builder.pos + skipped, txt);
            builder.col += skipped;
            builder.pos += skipped;
          }
          if (!m) break;
          pos += skipped + 1;
          if (m[0] == "\t") {
            var tabSize = builder.cm.options.tabSize, tabWidth = tabSize - builder.col % tabSize;
            var txt = content.appendChild(elt("span", spaceStr(tabWidth), "cm-tab"));
            txt.setAttribute("role", "presentation");
            txt.setAttribute("cm-text", "\t");
            builder.col += tabWidth;
          } else if (m[0] == "\r" || m[0] == "\n") {
            var txt = content.appendChild(elt("span", m[0] == "\r" ? "\u240d" : "\u2424", "cm-invalidchar"));
            txt.setAttribute("cm-text", m[0]);
            builder.col += 1;
          } else {
            var txt = builder.cm.options.specialCharPlaceholder(m[0]);
            txt.setAttribute("cm-text", m[0]);
            if (ie && ie_version < 9) content.appendChild(elt("span", [txt]));
            else content.appendChild(txt);
            builder.col += 1;
          }
          builder.map.push(builder.pos, builder.pos + 1, txt);
          builder.pos++;
        }
      }
      if (style || startStyle || endStyle || mustWrap || css) {
        var fullStyle = style || "";
        if (startStyle) fullStyle += startStyle;
        if (endStyle) fullStyle += endStyle;
        var token = elt("span", [content], fullStyle, css);
        if (title) token.title = title;
        return builder.content.appendChild(token);
      }
      builder.content.appendChild(content);
    }
  
    function splitSpaces(old) {
      var out = " ";
      for (var i = 0; i < old.length - 2; ++i) out += i % 2 ? " " : "\u00a0";
      out += " ";
      return out;
    }
  
    // Work around nonsense dimensions being reported for stretches of
    // right-to-left text.
    function buildTokenBadBidi(inner, order) {
      return function(builder, text, style, startStyle, endStyle, title, css) {
        style = style ? style + " cm-force-border" : "cm-force-border";
        var start = builder.pos, end = start + text.length;
        for (;;) {
          // Find the part that overlaps with the start of this text
          for (var i = 0; i < order.length; i++) {
            var part = order[i];
            if (part.to > start && part.from <= start) break;
          }
          if (part.to >= end) return inner(builder, text, style, startStyle, endStyle, title, css);
          inner(builder, text.slice(0, part.to - start), style, startStyle, null, title, css);
          startStyle = null;
          text = text.slice(part.to - start);
          start = part.to;
        }
      };
    }
  
    function buildCollapsedSpan(builder, size, marker, ignoreWidget) {
      var widget = !ignoreWidget && marker.widgetNode;
      if (widget) builder.map.push(builder.pos, builder.pos + size, widget);
      if (!ignoreWidget && builder.cm.display.input.needsContentAttribute) {
        if (!widget)
          widget = builder.content.appendChild(document.createElement("span"));
        widget.setAttribute("cm-marker", marker.id);
      }
      if (widget) {
        builder.cm.display.input.setUneditable(widget);
        builder.content.appendChild(widget);
      }
      builder.pos += size;
    }
  
    // Outputs a number of spans to make up a line, taking highlighting
    // and marked text into account.
    function insertLineContent(line, builder, styles) {
      var spans = line.markedSpans, allText = line.text, at = 0;
      if (!spans) {
        for (var i = 1; i < styles.length; i+=2)
          builder.addToken(builder, allText.slice(at, at = styles[i]), interpretTokenStyle(styles[i+1], builder.cm.options));
        return;
      }
  
      var len = allText.length, pos = 0, i = 1, text = "", style, css;
      var nextChange = 0, spanStyle, spanEndStyle, spanStartStyle, title, collapsed;
      for (;;) {
        if (nextChange == pos) { // Update current marker set
          spanStyle = spanEndStyle = spanStartStyle = title = css = "";
          collapsed = null; nextChange = Infinity;
          var foundBookmarks = [], endStyles
          for (var j = 0; j < spans.length; ++j) {
            var sp = spans[j], m = sp.marker;
            if (m.type == "bookmark" && sp.from == pos && m.widgetNode) {
              foundBookmarks.push(m);
            } else if (sp.from <= pos && (sp.to == null || sp.to > pos || m.collapsed && sp.to == pos && sp.from == pos)) {
              if (sp.to != null && sp.to != pos && nextChange > sp.to) {
                nextChange = sp.to;
                spanEndStyle = "";
              }
              if (m.className) spanStyle += " " + m.className;
              if (m.css) css = (css ? css + ";" : "") + m.css;
              if (m.startStyle && sp.from == pos) spanStartStyle += " " + m.startStyle;
              if (m.endStyle && sp.to == nextChange) (endStyles || (endStyles = [])).push(m.endStyle, sp.to)
              if (m.title && !title) title = m.title;
              if (m.collapsed && (!collapsed || compareCollapsedMarkers(collapsed.marker, m) < 0))
                collapsed = sp;
            } else if (sp.from > pos && nextChange > sp.from) {
              nextChange = sp.from;
            }
          }
          if (endStyles) for (var j = 0; j < endStyles.length; j += 2)
            if (endStyles[j + 1] == nextChange) spanEndStyle += " " + endStyles[j]
  
          if (!collapsed || collapsed.from == pos) for (var j = 0; j < foundBookmarks.length; ++j)
            buildCollapsedSpan(builder, 0, foundBookmarks[j]);
          if (collapsed && (collapsed.from || 0) == pos) {
            buildCollapsedSpan(builder, (collapsed.to == null ? len + 1 : collapsed.to) - pos,
                               collapsed.marker, collapsed.from == null);
            if (collapsed.to == null) return;
            if (collapsed.to == pos) collapsed = false;
          }
        }
        if (pos >= len) break;
  
        var upto = Math.min(len, nextChange);
        while (true) {
          if (text) {
            var end = pos + text.length;
            if (!collapsed) {
              var tokenText = end > upto ? text.slice(0, upto - pos) : text;
              builder.addToken(builder, tokenText, style ? style + spanStyle : spanStyle,
                               spanStartStyle, pos + tokenText.length == nextChange ? spanEndStyle : "", title, css);
            }
            if (end >= upto) {text = text.slice(upto - pos); pos = upto; break;}
            pos = end;
            spanStartStyle = "";
          }
          text = allText.slice(at, at = styles[i++]);
          style = interpretTokenStyle(styles[i++], builder.cm.options);
        }
      }
    }
  
    // DOCUMENT DATA STRUCTURE
  
    // By default, updates that start and end at the beginning of a line
    // are treated specially, in order to make the association of line
    // widgets and marker elements with the text behave more intuitive.
    function isWholeLineUpdate(doc, change) {
      return change.from.ch == 0 && change.to.ch == 0 && lst(change.text) == "" &&
        (!doc.cm || doc.cm.options.wholeLineUpdateBefore);
    }
  
    // Perform a change on the document data structure.
    function updateDoc(doc, change, markedSpans, estimateHeight) {
      function spansFor(n) {return markedSpans ? markedSpans[n] : null;}
      function update(line, text, spans) {
        updateLine(line, text, spans, estimateHeight);
        signalLater(line, "change", line, change);
      }
      function linesFor(start, end) {
        for (var i = start, result = []; i < end; ++i)
          result.push(new Line(text[i], spansFor(i), estimateHeight));
        return result;
      }
  
      var from = change.from, to = change.to, text = change.text;
      var firstLine = getLine(doc, from.line), lastLine = getLine(doc, to.line);
      var lastText = lst(text), lastSpans = spansFor(text.length - 1), nlines = to.line - from.line;
  
      // Adjust the line structure
      if (change.full) {
        doc.insert(0, linesFor(0, text.length));
        doc.remove(text.length, doc.size - text.length);
      } else if (isWholeLineUpdate(doc, change)) {
        // This is a whole-line replace. Treated specially to make
        // sure line objects move the way they are supposed to.
        var added = linesFor(0, text.length - 1);
        update(lastLine, lastLine.text, lastSpans);
        if (nlines) doc.remove(from.line, nlines);
        if (added.length) doc.insert(from.line, added);
      } else if (firstLine == lastLine) {
        if (text.length == 1) {
          update(firstLine, firstLine.text.slice(0, from.ch) + lastText + firstLine.text.slice(to.ch), lastSpans);
        } else {
          var added = linesFor(1, text.length - 1);
          added.push(new Line(lastText + firstLine.text.slice(to.ch), lastSpans, estimateHeight));
          update(firstLine, firstLine.text.slice(0, from.ch) + text[0], spansFor(0));
          doc.insert(from.line + 1, added);
        }
      } else if (text.length == 1) {
        update(firstLine, firstLine.text.slice(0, from.ch) + text[0] + lastLine.text.slice(to.ch), spansFor(0));
        doc.remove(from.line + 1, nlines);
      } else {
        update(firstLine, firstLine.text.slice(0, from.ch) + text[0], spansFor(0));
        update(lastLine, lastText + lastLine.text.slice(to.ch), lastSpans);
        var added = linesFor(1, text.length - 1);
        if (nlines > 1) doc.remove(from.line + 1, nlines - 1);
        doc.insert(from.line + 1, added);
      }
  
      signalLater(doc, "change", doc, change);
    }
  
    // The document is represented as a BTree consisting of leaves, with
    // chunk of lines in them, and branches, with up to ten leaves or
    // other branch nodes below them. The top node is always a branch
    // node, and is the document object itself (meaning it has
    // additional methods and properties).
    //
    // All nodes have parent links. The tree is used both to go from
    // line numbers to line objects, and to go from objects to numbers.
    // It also indexes by height, and is used to convert between height
    // and line object, and to find the total height of the document.
    //
    // See also http://marijnhaverbeke.nl/blog/codemirror-line-tree.html
  
    function LeafChunk(lines) {
      this.lines = lines;
      this.parent = null;
      for (var i = 0, height = 0; i < lines.length; ++i) {
        lines[i].parent = this;
        height += lines[i].height;
      }
      this.height = height;
    }
  
    LeafChunk.prototype = {
      chunkSize: function() { return this.lines.length; },
      // Remove the n lines at offset 'at'.
      removeInner: function(at, n) {
        for (var i = at, e = at + n; i < e; ++i) {
          var line = this.lines[i];
          this.height -= line.height;
          cleanUpLine(line);
          signalLater(line, "delete");
        }
        this.lines.splice(at, n);
      },
      // Helper used to collapse a small branch into a single leaf.
      collapse: function(lines) {
        lines.push.apply(lines, this.lines);
      },
      // Insert the given array of lines at offset 'at', count them as
      // having the given height.
      insertInner: function(at, lines, height) {
        this.height += height;
        this.lines = this.lines.slice(0, at).concat(lines).concat(this.lines.slice(at));
        for (var i = 0; i < lines.length; ++i) lines[i].parent = this;
      },
      // Used to iterate over a part of the tree.
      iterN: function(at, n, op) {
        for (var e = at + n; at < e; ++at)
          if (op(this.lines[at])) return true;
      }
    };
  
    function BranchChunk(children) {
      this.children = children;
      var size = 0, height = 0;
      for (var i = 0; i < children.length; ++i) {
        var ch = children[i];
        size += ch.chunkSize(); height += ch.height;
        ch.parent = this;
      }
      this.size = size;
      this.height = height;
      this.parent = null;
    }
  
    BranchChunk.prototype = {
      chunkSize: function() { return this.size; },
      removeInner: function(at, n) {
        this.size -= n;
        for (var i = 0; i < this.children.length; ++i) {
          var child = this.children[i], sz = child.chunkSize();
          if (at < sz) {
            var rm = Math.min(n, sz - at), oldHeight = child.height;
            child.removeInner(at, rm);
            this.height -= oldHeight - child.height;
            if (sz == rm) { this.children.splice(i--, 1); child.parent = null; }
            if ((n -= rm) == 0) break;
            at = 0;
          } else at -= sz;
        }
        // If the result is smaller than 25 lines, ensure that it is a
        // single leaf node.
        if (this.size - n < 25 &&
            (this.children.length > 1 || !(this.children[0] instanceof LeafChunk))) {
          var lines = [];
          this.collapse(lines);
          this.children = [new LeafChunk(lines)];
          this.children[0].parent = this;
        }
      },
      collapse: function(lines) {
        for (var i = 0; i < this.children.length; ++i) this.children[i].collapse(lines);
      },
      insertInner: function(at, lines, height) {
        this.size += lines.length;
        this.height += height;
        for (var i = 0; i < this.children.length; ++i) {
          var child = this.children[i], sz = child.chunkSize();
          if (at <= sz) {
            child.insertInner(at, lines, height);
            if (child.lines && child.lines.length > 50) {
              while (child.lines.length > 50) {
                var spilled = child.lines.splice(child.lines.length - 25, 25);
                var newleaf = new LeafChunk(spilled);
                child.height -= newleaf.height;
                this.children.splice(i + 1, 0, newleaf);
                newleaf.parent = this;
              }
              this.maybeSpill();
            }
            break;
          }
          at -= sz;
        }
      },
      // When a node has grown, check whether it should be split.
      maybeSpill: function() {
        if (this.children.length <= 10) return;
        var me = this;
        do {
          var spilled = me.children.splice(me.children.length - 5, 5);
          var sibling = new BranchChunk(spilled);
          if (!me.parent) { // Become the parent node
            var copy = new BranchChunk(me.children);
            copy.parent = me;
            me.children = [copy, sibling];
            me = copy;
          } else {
            me.size -= sibling.size;
            me.height -= sibling.height;
            var myIndex = indexOf(me.parent.children, me);
            me.parent.children.splice(myIndex + 1, 0, sibling);
          }
          sibling.parent = me.parent;
        } while (me.children.length > 10);
        me.parent.maybeSpill();
      },
      iterN: function(at, n, op) {
        for (var i = 0; i < this.children.length; ++i) {
          var child = this.children[i], sz = child.chunkSize();
          if (at < sz) {
            var used = Math.min(n, sz - at);
            if (child.iterN(at, used, op)) return true;
            if ((n -= used) == 0) break;
            at = 0;
          } else at -= sz;
        }
      }
    };
  
    var nextDocId = 0;
    var Doc = CodeMirror.Doc = function(text, mode, firstLine, lineSep) {
      if (!(this instanceof Doc)) return new Doc(text, mode, firstLine, lineSep);
      if (firstLine == null) firstLine = 0;
  
      BranchChunk.call(this, [new LeafChunk([new Line("", null)])]);
      this.first = firstLine;
      this.scrollTop = this.scrollLeft = 0;
      this.cantEdit = false;
      this.cleanGeneration = 1;
      this.frontier = firstLine;
      var start = Pos(firstLine, 0);
      this.sel = simpleSelection(start);
      this.history = new History(null);
      this.id = ++nextDocId;
      this.modeOption = mode;
      this.lineSep = lineSep;
      this.extend = false;
  
      if (typeof text == "string") text = this.splitLines(text);
      updateDoc(this, {from: start, to: start, text: text});
      setSelection(this, simpleSelection(start), sel_dontScroll);
    };
  
    Doc.prototype = createObj(BranchChunk.prototype, {
      constructor: Doc,
      // Iterate over the document. Supports two forms -- with only one
      // argument, it calls that for each line in the document. With
      // three, it iterates over the range given by the first two (with
      // the second being non-inclusive).
      iter: function(from, to, op) {
        if (op) this.iterN(from - this.first, to - from, op);
        else this.iterN(this.first, this.first + this.size, from);
      },
  
      // Non-public interface for adding and removing lines.
      insert: function(at, lines) {
        var height = 0;
        for (var i = 0; i < lines.length; ++i) height += lines[i].height;
        this.insertInner(at - this.first, lines, height);
      },
      remove: function(at, n) { this.removeInner(at - this.first, n); },
  
      // From here, the methods are part of the public interface. Most
      // are also available from CodeMirror (editor) instances.
  
      getValue: function(lineSep) {
        var lines = getLines(this, this.first, this.first + this.size);
        if (lineSep === false) return lines;
        return lines.join(lineSep || this.lineSeparator());
      },
      setValue: docMethodOp(function(code) {
        var top = Pos(this.first, 0), last = this.first + this.size - 1;
        makeChange(this, {from: top, to: Pos(last, getLine(this, last).text.length),
                          text: this.splitLines(code), origin: "setValue", full: true}, true);
        setSelection(this, simpleSelection(top));
      }),
      replaceRange: function(code, from, to, origin) {
        from = clipPos(this, from);
        to = to ? clipPos(this, to) : from;
        replaceRange(this, code, from, to, origin);
      },
      getRange: function(from, to, lineSep) {
        var lines = getBetween(this, clipPos(this, from), clipPos(this, to));
        if (lineSep === false) return lines;
        return lines.join(lineSep || this.lineSeparator());
      },
  
      getLine: function(line) {var l = this.getLineHandle(line); return l && l.text;},
  
      getLineHandle: function(line) {if (isLine(this, line)) return getLine(this, line);},
      getLineNumber: function(line) {return lineNo(line);},
  
      getLineHandleVisualStart: function(line) {
        if (typeof line == "number") line = getLine(this, line);
        return visualLine(line);
      },
  
      lineCount: function() {return this.size;},
      firstLine: function() {return this.first;},
      lastLine: function() {return this.first + this.size - 1;},
  
      clipPos: function(pos) {return clipPos(this, pos);},
  
      getCursor: function(start) {
        var range = this.sel.primary(), pos;
        if (start == null || start == "head") pos = range.head;
        else if (start == "anchor") pos = range.anchor;
        else if (start == "end" || start == "to" || start === false) pos = range.to();
        else pos = range.from();
        return pos;
      },
      listSelections: function() { return this.sel.ranges; },
      somethingSelected: function() {return this.sel.somethingSelected();},
  
      setCursor: docMethodOp(function(line, ch, options) {
        setSimpleSelection(this, clipPos(this, typeof line == "number" ? Pos(line, ch || 0) : line), null, options);
      }),
      setSelection: docMethodOp(function(anchor, head, options) {
        setSimpleSelection(this, clipPos(this, anchor), clipPos(this, head || anchor), options);
      }),
      extendSelection: docMethodOp(function(head, other, options) {
        extendSelection(this, clipPos(this, head), other && clipPos(this, other), options);
      }),
      extendSelections: docMethodOp(function(heads, options) {
        extendSelections(this, clipPosArray(this, heads), options);
      }),
      extendSelectionsBy: docMethodOp(function(f, options) {
        var heads = map(this.sel.ranges, f);
        extendSelections(this, clipPosArray(this, heads), options);
      }),
      setSelections: docMethodOp(function(ranges, primary, options) {
        if (!ranges.length) return;
        for (var i = 0, out = []; i < ranges.length; i++)
          out[i] = new Range(clipPos(this, ranges[i].anchor),
                             clipPos(this, ranges[i].head));
        if (primary == null) primary = Math.min(ranges.length - 1, this.sel.primIndex);
        setSelection(this, normalizeSelection(out, primary), options);
      }),
      addSelection: docMethodOp(function(anchor, head, options) {
        var ranges = this.sel.ranges.slice(0);
        ranges.push(new Range(clipPos(this, anchor), clipPos(this, head || anchor)));
        setSelection(this, normalizeSelection(ranges, ranges.length - 1), options);
      }),
  
      getSelection: function(lineSep) {
        var ranges = this.sel.ranges, lines;
        for (var i = 0; i < ranges.length; i++) {
          var sel = getBetween(this, ranges[i].from(), ranges[i].to());
          lines = lines ? lines.concat(sel) : sel;
        }
        if (lineSep === false) return lines;
        else return lines.join(lineSep || this.lineSeparator());
      },
      getSelections: function(lineSep) {
        var parts = [], ranges = this.sel.ranges;
        for (var i = 0; i < ranges.length; i++) {
          var sel = getBetween(this, ranges[i].from(), ranges[i].to());
          if (lineSep !== false) sel = sel.join(lineSep || this.lineSeparator());
          parts[i] = sel;
        }
        return parts;
      },
      replaceSelection: function(code, collapse, origin) {
        var dup = [];
        for (var i = 0; i < this.sel.ranges.length; i++)
          dup[i] = code;
        this.replaceSelections(dup, collapse, origin || "+input");
      },
      replaceSelections: docMethodOp(function(code, collapse, origin) {
        var changes = [], sel = this.sel;
        for (var i = 0; i < sel.ranges.length; i++) {
          var range = sel.ranges[i];
          changes[i] = {from: range.from(), to: range.to(), text: this.splitLines(code[i]), origin: origin};
        }
        var newSel = collapse && collapse != "end" && computeReplacedSel(this, changes, collapse);
        for (var i = changes.length - 1; i >= 0; i--)
          makeChange(this, changes[i]);
        if (newSel) setSelectionReplaceHistory(this, newSel);
        else if (this.cm) ensureCursorVisible(this.cm);
      }),
      undo: docMethodOp(function() {makeChangeFromHistory(this, "undo");}),
      redo: docMethodOp(function() {makeChangeFromHistory(this, "redo");}),
      undoSelection: docMethodOp(function() {makeChangeFromHistory(this, "undo", true);}),
      redoSelection: docMethodOp(function() {makeChangeFromHistory(this, "redo", true);}),
  
      setExtending: function(val) {this.extend = val;},
      getExtending: function() {return this.extend;},
  
      historySize: function() {
        var hist = this.history, done = 0, undone = 0;
        for (var i = 0; i < hist.done.length; i++) if (!hist.done[i].ranges) ++done;
        for (var i = 0; i < hist.undone.length; i++) if (!hist.undone[i].ranges) ++undone;
        return {undo: done, redo: undone};
      },
      clearHistory: function() {this.history = new History(this.history.maxGeneration);},
  
      markClean: function() {
        this.cleanGeneration = this.changeGeneration(true);
      },
      changeGeneration: function(forceSplit) {
        if (forceSplit)
          this.history.lastOp = this.history.lastSelOp = this.history.lastOrigin = null;
        return this.history.generation;
      },
      isClean: function (gen) {
        return this.history.generation == (gen || this.cleanGeneration);
      },
  
      getHistory: function() {
        return {done: copyHistoryArray(this.history.done),
                undone: copyHistoryArray(this.history.undone)};
      },
      setHistory: function(histData) {
        var hist = this.history = new History(this.history.maxGeneration);
        hist.done = copyHistoryArray(histData.done.slice(0), null, true);
        hist.undone = copyHistoryArray(histData.undone.slice(0), null, true);
      },
  
      addLineClass: docMethodOp(function(handle, where, cls) {
        return changeLine(this, handle, where == "gutter" ? "gutter" : "class", function(line) {
          var prop = where == "text" ? "textClass"
                   : where == "background" ? "bgClass"
                   : where == "gutter" ? "gutterClass" : "wrapClass";
          if (!line[prop]) line[prop] = cls;
          else if (classTest(cls).test(line[prop])) return false;
          else line[prop] += " " + cls;
          return true;
        });
      }),
      removeLineClass: docMethodOp(function(handle, where, cls) {
        return changeLine(this, handle, where == "gutter" ? "gutter" : "class", function(line) {
          var prop = where == "text" ? "textClass"
                   : where == "background" ? "bgClass"
                   : where == "gutter" ? "gutterClass" : "wrapClass";
          var cur = line[prop];
          if (!cur) return false;
          else if (cls == null) line[prop] = null;
          else {
            var found = cur.match(classTest(cls));
            if (!found) return false;
            var end = found.index + found[0].length;
            line[prop] = cur.slice(0, found.index) + (!found.index || end == cur.length ? "" : " ") + cur.slice(end) || null;
          }
          return true;
        });
      }),
  
      addLineWidget: docMethodOp(function(handle, node, options) {
        return addLineWidget(this, handle, node, options);
      }),
      removeLineWidget: function(widget) { widget.clear(); },
  
      markText: function(from, to, options) {
        return markText(this, clipPos(this, from), clipPos(this, to), options, options && options.type || "range");
      },
      setBookmark: function(pos, options) {
        var realOpts = {replacedWith: options && (options.nodeType == null ? options.widget : options),
                        insertLeft: options && options.insertLeft,
                        clearWhenEmpty: false, shared: options && options.shared,
                        handleMouseEvents: options && options.handleMouseEvents};
        pos = clipPos(this, pos);
        return markText(this, pos, pos, realOpts, "bookmark");
      },
      findMarksAt: function(pos) {
        pos = clipPos(this, pos);
        var markers = [], spans = getLine(this, pos.line).markedSpans;
        if (spans) for (var i = 0; i < spans.length; ++i) {
          var span = spans[i];
          if ((span.from == null || span.from <= pos.ch) &&
              (span.to == null || span.to >= pos.ch))
            markers.push(span.marker.parent || span.marker);
        }
        return markers;
      },
      findMarks: function(from, to, filter) {
        from = clipPos(this, from); to = clipPos(this, to);
        var found = [], lineNo = from.line;
        this.iter(from.line, to.line + 1, function(line) {
          var spans = line.markedSpans;
          if (spans) for (var i = 0; i < spans.length; i++) {
            var span = spans[i];
            if (!(span.to != null && lineNo == from.line && from.ch > span.to ||
                  span.from == null && lineNo != from.line ||
                  span.from != null && lineNo == to.line && span.from > to.ch) &&
                (!filter || filter(span.marker)))
              found.push(span.marker.parent || span.marker);
          }
          ++lineNo;
        });
        return found;
      },
      getAllMarks: function() {
        var markers = [];
        this.iter(function(line) {
          var sps = line.markedSpans;
          if (sps) for (var i = 0; i < sps.length; ++i)
            if (sps[i].from != null) markers.push(sps[i].marker);
        });
        return markers;
      },
  
      posFromIndex: function(off) {
        var ch, lineNo = this.first;
        this.iter(function(line) {
          var sz = line.text.length + 1;
          if (sz > off) { ch = off; return true; }
          off -= sz;
          ++lineNo;
        });
        return clipPos(this, Pos(lineNo, ch));
      },
      indexFromPos: function (coords) {
        coords = clipPos(this, coords);
        var index = coords.ch;
        if (coords.line < this.first || coords.ch < 0) return 0;
        this.iter(this.first, coords.line, function (line) {
          index += line.text.length + 1;
        });
        return index;
      },
  
      copy: function(copyHistory) {
        var doc = new Doc(getLines(this, this.first, this.first + this.size),
                          this.modeOption, this.first, this.lineSep);
        doc.scrollTop = this.scrollTop; doc.scrollLeft = this.scrollLeft;
        doc.sel = this.sel;
        doc.extend = false;
        if (copyHistory) {
          doc.history.undoDepth = this.history.undoDepth;
          doc.setHistory(this.getHistory());
        }
        return doc;
      },
  
      linkedDoc: function(options) {
        if (!options) options = {};
        var from = this.first, to = this.first + this.size;
        if (options.from != null && options.from > from) from = options.from;
        if (options.to != null && options.to < to) to = options.to;
        var copy = new Doc(getLines(this, from, to), options.mode || this.modeOption, from, this.lineSep);
        if (options.sharedHist) copy.history = this.history;
        (this.linked || (this.linked = [])).push({doc: copy, sharedHist: options.sharedHist});
        copy.linked = [{doc: this, isParent: true, sharedHist: options.sharedHist}];
        copySharedMarkers(copy, findSharedMarkers(this));
        return copy;
      },
      unlinkDoc: function(other) {
        if (other instanceof CodeMirror) other = other.doc;
        if (this.linked) for (var i = 0; i < this.linked.length; ++i) {
          var link = this.linked[i];
          if (link.doc != other) continue;
          this.linked.splice(i, 1);
          other.unlinkDoc(this);
          detachSharedMarkers(findSharedMarkers(this));
          break;
        }
        // If the histories were shared, split them again
        if (other.history == this.history) {
          var splitIds = [other.id];
          linkedDocs(other, function(doc) {splitIds.push(doc.id);}, true);
          other.history = new History(null);
          other.history.done = copyHistoryArray(this.history.done, splitIds);
          other.history.undone = copyHistoryArray(this.history.undone, splitIds);
        }
      },
      iterLinkedDocs: function(f) {linkedDocs(this, f);},
  
      getMode: function() {return this.mode;},
      getEditor: function() {return this.cm;},
  
      splitLines: function(str) {
        if (this.lineSep) return str.split(this.lineSep);
        return splitLinesAuto(str);
      },
      lineSeparator: function() { return this.lineSep || "\n"; }
    });
  
    // Public alias.
    Doc.prototype.eachLine = Doc.prototype.iter;
  
    // Set up methods on CodeMirror's prototype to redirect to the editor's document.
    var dontDelegate = "iter insert remove copy getEditor constructor".split(" ");
    for (var prop in Doc.prototype) if (Doc.prototype.hasOwnProperty(prop) && indexOf(dontDelegate, prop) < 0)
      CodeMirror.prototype[prop] = (function(method) {
        return function() {return method.apply(this.doc, arguments);};
      })(Doc.prototype[prop]);
  
    eventMixin(Doc);
  
    // Call f for all linked documents.
    function linkedDocs(doc, f, sharedHistOnly) {
      function propagate(doc, skip, sharedHist) {
        if (doc.linked) for (var i = 0; i < doc.linked.length; ++i) {
          var rel = doc.linked[i];
          if (rel.doc == skip) continue;
          var shared = sharedHist && rel.sharedHist;
          if (sharedHistOnly && !shared) continue;
          f(rel.doc, shared);
          propagate(rel.doc, doc, shared);
        }
      }
      propagate(doc, null, true);
    }
  
    // Attach a document to an editor.
    function attachDoc(cm, doc) {
      if (doc.cm) throw new Error("This document is already in use.");
      cm.doc = doc;
      doc.cm = cm;
      estimateLineHeights(cm);
      loadMode(cm);
      if (!cm.options.lineWrapping) findMaxLine(cm);
      cm.options.mode = doc.modeOption;
      regChange(cm);
    }
  
    // LINE UTILITIES
  
    // Find the line object corresponding to the given line number.
    function getLine(doc, n) {
      n -= doc.first;
      if (n < 0 || n >= doc.size) throw new Error("There is no line " + (n + doc.first) + " in the document.");
      for (var chunk = doc; !chunk.lines;) {
        for (var i = 0;; ++i) {
          var child = chunk.children[i], sz = child.chunkSize();
          if (n < sz) { chunk = child; break; }
          n -= sz;
        }
      }
      return chunk.lines[n];
    }
  
    // Get the part of a document between two positions, as an array of
    // strings.
    function getBetween(doc, start, end) {
      var out = [], n = start.line;
      doc.iter(start.line, end.line + 1, function(line) {
        var text = line.text;
        if (n == end.line) text = text.slice(0, end.ch);
        if (n == start.line) text = text.slice(start.ch);
        out.push(text);
        ++n;
      });
      return out;
    }
    // Get the lines between from and to, as array of strings.
    function getLines(doc, from, to) {
      var out = [];
      doc.iter(from, to, function(line) { out.push(line.text); });
      return out;
    }
  
    // Update the height of a line, propagating the height change
    // upwards to parent nodes.
    function updateLineHeight(line, height) {
      var diff = height - line.height;
      if (diff) for (var n = line; n; n = n.parent) n.height += diff;
    }
  
    // Given a line object, find its line number by walking up through
    // its parent links.
    function lineNo(line) {
      if (line.parent == null) return null;
      var cur = line.parent, no = indexOf(cur.lines, line);
      for (var chunk = cur.parent; chunk; cur = chunk, chunk = chunk.parent) {
        for (var i = 0;; ++i) {
          if (chunk.children[i] == cur) break;
          no += chunk.children[i].chunkSize();
        }
      }
      return no + cur.first;
    }
  
    // Find the line at the given vertical position, using the height
    // information in the document tree.
    function lineAtHeight(chunk, h) {
      var n = chunk.first;
      outer: do {
        for (var i = 0; i < chunk.children.length; ++i) {
          var child = chunk.children[i], ch = child.height;
          if (h < ch) { chunk = child; continue outer; }
          h -= ch;
          n += child.chunkSize();
        }
        return n;
      } while (!chunk.lines);
      for (var i = 0; i < chunk.lines.length; ++i) {
        var line = chunk.lines[i], lh = line.height;
        if (h < lh) break;
        h -= lh;
      }
      return n + i;
    }
  
  
    // Find the height above the given line.
    function heightAtLine(lineObj) {
      lineObj = visualLine(lineObj);
  
      var h = 0, chunk = lineObj.parent;
      for (var i = 0; i < chunk.lines.length; ++i) {
        var line = chunk.lines[i];
        if (line == lineObj) break;
        else h += line.height;
      }
      for (var p = chunk.parent; p; chunk = p, p = chunk.parent) {
        for (var i = 0; i < p.children.length; ++i) {
          var cur = p.children[i];
          if (cur == chunk) break;
          else h += cur.height;
        }
      }
      return h;
    }
  
    // Get the bidi ordering for the given line (and cache it). Returns
    // false for lines that are fully left-to-right, and an array of
    // BidiSpan objects otherwise.
    function getOrder(line) {
      var order = line.order;
      if (order == null) order = line.order = bidiOrdering(line.text);
      return order;
    }
  
    // HISTORY
  
    function History(startGen) {
      // Arrays of change events and selections. Doing something adds an
      // event to done and clears undo. Undoing moves events from done
      // to undone, redoing moves them in the other direction.
      this.done = []; this.undone = [];
      this.undoDepth = Infinity;
      // Used to track when changes can be merged into a single undo
      // event
      this.lastModTime = this.lastSelTime = 0;
      this.lastOp = this.lastSelOp = null;
      this.lastOrigin = this.lastSelOrigin = null;
      // Used by the isClean() method
      this.generation = this.maxGeneration = startGen || 1;
    }
  
    // Create a history change event from an updateDoc-style change
    // object.
    function historyChangeFromChange(doc, change) {
      var histChange = {from: copyPos(change.from), to: changeEnd(change), text: getBetween(doc, change.from, change.to)};
      attachLocalSpans(doc, histChange, change.from.line, change.to.line + 1);
      linkedDocs(doc, function(doc) {attachLocalSpans(doc, histChange, change.from.line, change.to.line + 1);}, true);
      return histChange;
    }
  
    // Pop all selection events off the end of a history array. Stop at
    // a change event.
    function clearSelectionEvents(array) {
      while (array.length) {
        var last = lst(array);
        if (last.ranges) array.pop();
        else break;
      }
    }
  
    // Find the top change event in the history. Pop off selection
    // events that are in the way.
    function lastChangeEvent(hist, force) {
      if (force) {
        clearSelectionEvents(hist.done);
        return lst(hist.done);
      } else if (hist.done.length && !lst(hist.done).ranges) {
        return lst(hist.done);
      } else if (hist.done.length > 1 && !hist.done[hist.done.length - 2].ranges) {
        hist.done.pop();
        return lst(hist.done);
      }
    }
  
    // Register a change in the history. Merges changes that are within
    // a single operation, ore are close together with an origin that
    // allows merging (starting with "+") into a single event.
    function addChangeToHistory(doc, change, selAfter, opId) {
      var hist = doc.history;
      hist.undone.length = 0;
      var time = +new Date, cur;
  
      if ((hist.lastOp == opId ||
           hist.lastOrigin == change.origin && change.origin &&
           ((change.origin.charAt(0) == "+" && doc.cm && hist.lastModTime > time - doc.cm.options.historyEventDelay) ||
            change.origin.charAt(0) == "*")) &&
          (cur = lastChangeEvent(hist, hist.lastOp == opId))) {
        // Merge this change into the last event
        var last = lst(cur.changes);
        if (cmp(change.from, change.to) == 0 && cmp(change.from, last.to) == 0) {
          // Optimized case for simple insertion -- don't want to add
          // new changesets for every character typed
          last.to = changeEnd(change);
        } else {
          // Add new sub-event
          cur.changes.push(historyChangeFromChange(doc, change));
        }
      } else {
        // Can not be merged, start a new event.
        var before = lst(hist.done);
        if (!before || !before.ranges)
          pushSelectionToHistory(doc.sel, hist.done);
        cur = {changes: [historyChangeFromChange(doc, change)],
               generation: hist.generation};
        hist.done.push(cur);
        while (hist.done.length > hist.undoDepth) {
          hist.done.shift();
          if (!hist.done[0].ranges) hist.done.shift();
        }
      }
      hist.done.push(selAfter);
      hist.generation = ++hist.maxGeneration;
      hist.lastModTime = hist.lastSelTime = time;
      hist.lastOp = hist.lastSelOp = opId;
      hist.lastOrigin = hist.lastSelOrigin = change.origin;
  
      if (!last) signal(doc, "historyAdded");
    }
  
    function selectionEventCanBeMerged(doc, origin, prev, sel) {
      var ch = origin.charAt(0);
      return ch == "*" ||
        ch == "+" &&
        prev.ranges.length == sel.ranges.length &&
        prev.somethingSelected() == sel.somethingSelected() &&
        new Date - doc.history.lastSelTime <= (doc.cm ? doc.cm.options.historyEventDelay : 500);
    }
  
    // Called whenever the selection changes, sets the new selection as
    // the pending selection in the history, and pushes the old pending
    // selection into the 'done' array when it was significantly
    // different (in number of selected ranges, emptiness, or time).
    function addSelectionToHistory(doc, sel, opId, options) {
      var hist = doc.history, origin = options && options.origin;
  
      // A new event is started when the previous origin does not match
      // the current, or the origins don't allow matching. Origins
      // starting with * are always merged, those starting with + are
      // merged when similar and close together in time.
      if (opId == hist.lastSelOp ||
          (origin && hist.lastSelOrigin == origin &&
           (hist.lastModTime == hist.lastSelTime && hist.lastOrigin == origin ||
            selectionEventCanBeMerged(doc, origin, lst(hist.done), sel))))
        hist.done[hist.done.length - 1] = sel;
      else
        pushSelectionToHistory(sel, hist.done);
  
      hist.lastSelTime = +new Date;
      hist.lastSelOrigin = origin;
      hist.lastSelOp = opId;
      if (options && options.clearRedo !== false)
        clearSelectionEvents(hist.undone);
    }
  
    function pushSelectionToHistory(sel, dest) {
      var top = lst(dest);
      if (!(top && top.ranges && top.equals(sel)))
        dest.push(sel);
    }
  
    // Used to store marked span information in the history.
    function attachLocalSpans(doc, change, from, to) {
      var existing = change["spans_" + doc.id], n = 0;
      doc.iter(Math.max(doc.first, from), Math.min(doc.first + doc.size, to), function(line) {
        if (line.markedSpans)
          (existing || (existing = change["spans_" + doc.id] = {}))[n] = line.markedSpans;
        ++n;
      });
    }
  
    // When un/re-doing restores text containing marked spans, those
    // that have been explicitly cleared should not be restored.
    function removeClearedSpans(spans) {
      if (!spans) return null;
      for (var i = 0, out; i < spans.length; ++i) {
        if (spans[i].marker.explicitlyCleared) { if (!out) out = spans.slice(0, i); }
        else if (out) out.push(spans[i]);
      }
      return !out ? spans : out.length ? out : null;
    }
  
    // Retrieve and filter the old marked spans stored in a change event.
    function getOldSpans(doc, change) {
      var found = change["spans_" + doc.id];
      if (!found) return null;
      for (var i = 0, nw = []; i < change.text.length; ++i)
        nw.push(removeClearedSpans(found[i]));
      return nw;
    }
  
    // Used both to provide a JSON-safe object in .getHistory, and, when
    // detaching a document, to split the history in two
    function copyHistoryArray(events, newGroup, instantiateSel) {
      for (var i = 0, copy = []; i < events.length; ++i) {
        var event = events[i];
        if (event.ranges) {
          copy.push(instantiateSel ? Selection.prototype.deepCopy.call(event) : event);
          continue;
        }
        var changes = event.changes, newChanges = [];
        copy.push({changes: newChanges});
        for (var j = 0; j < changes.length; ++j) {
          var change = changes[j], m;
          newChanges.push({from: change.from, to: change.to, text: change.text});
          if (newGroup) for (var prop in change) if (m = prop.match(/^spans_(\d+)$/)) {
            if (indexOf(newGroup, Number(m[1])) > -1) {
              lst(newChanges)[prop] = change[prop];
              delete change[prop];
            }
          }
        }
      }
      return copy;
    }
  
    // Rebasing/resetting history to deal with externally-sourced changes
  
    function rebaseHistSelSingle(pos, from, to, diff) {
      if (to < pos.line) {
        pos.line += diff;
      } else if (from < pos.line) {
        pos.line = from;
        pos.ch = 0;
      }
    }
  
    // Tries to rebase an array of history events given a change in the
    // document. If the change touches the same lines as the event, the
    // event, and everything 'behind' it, is discarded. If the change is
    // before the event, the event's positions are updated. Uses a
    // copy-on-write scheme for the positions, to avoid having to
    // reallocate them all on every rebase, but also avoid problems with
    // shared position objects being unsafely updated.
    function rebaseHistArray(array, from, to, diff) {
      for (var i = 0; i < array.length; ++i) {
        var sub = array[i], ok = true;
        if (sub.ranges) {
          if (!sub.copied) { sub = array[i] = sub.deepCopy(); sub.copied = true; }
          for (var j = 0; j < sub.ranges.length; j++) {
            rebaseHistSelSingle(sub.ranges[j].anchor, from, to, diff);
            rebaseHistSelSingle(sub.ranges[j].head, from, to, diff);
          }
          continue;
        }
        for (var j = 0; j < sub.changes.length; ++j) {
          var cur = sub.changes[j];
          if (to < cur.from.line) {
            cur.from = Pos(cur.from.line + diff, cur.from.ch);
            cur.to = Pos(cur.to.line + diff, cur.to.ch);
          } else if (from <= cur.to.line) {
            ok = false;
            break;
          }
        }
        if (!ok) {
          array.splice(0, i + 1);
          i = 0;
        }
      }
    }
  
    function rebaseHist(hist, change) {
      var from = change.from.line, to = change.to.line, diff = change.text.length - (to - from) - 1;
      rebaseHistArray(hist.done, from, to, diff);
      rebaseHistArray(hist.undone, from, to, diff);
    }
  
    // EVENT UTILITIES
  
    // Due to the fact that we still support jurassic IE versions, some
    // compatibility wrappers are needed.
  
    var e_preventDefault = CodeMirror.e_preventDefault = function(e) {
      if (e.preventDefault) e.preventDefault();
      else e.returnValue = false;
    };
    var e_stopPropagation = CodeMirror.e_stopPropagation = function(e) {
      if (e.stopPropagation) e.stopPropagation();
      else e.cancelBubble = true;
    };
    function e_defaultPrevented(e) {
      return e.defaultPrevented != null ? e.defaultPrevented : e.returnValue == false;
    }
    var e_stop = CodeMirror.e_stop = function(e) {e_preventDefault(e); e_stopPropagation(e);};
  
    function e_target(e) {return e.target || e.srcElement;}
    function e_button(e) {
      var b = e.which;
      if (b == null) {
        if (e.button & 1) b = 1;
        else if (e.button & 2) b = 3;
        else if (e.button & 4) b = 2;
      }
      if (mac && e.ctrlKey && b == 1) b = 3;
      return b;
    }
  
    // EVENT HANDLING
  
    // Lightweight event framework. on/off also work on DOM nodes,
    // registering native DOM handlers.
  
    var on = CodeMirror.on = function(emitter, type, f) {
      if (emitter.addEventListener)
        emitter.addEventListener(type, f, false);
      else if (emitter.attachEvent)
        emitter.attachEvent("on" + type, f);
      else {
        var map = emitter._handlers || (emitter._handlers = {});
        var arr = map[type] || (map[type] = []);
        arr.push(f);
      }
    };
  
    var noHandlers = []
    function getHandlers(emitter, type, copy) {
      var arr = emitter._handlers && emitter._handlers[type]
      if (copy) return arr && arr.length > 0 ? arr.slice() : noHandlers
      else return arr || noHandlers
    }
  
    var off = CodeMirror.off = function(emitter, type, f) {
      if (emitter.removeEventListener)
        emitter.removeEventListener(type, f, false);
      else if (emitter.detachEvent)
        emitter.detachEvent("on" + type, f);
      else {
        var handlers = getHandlers(emitter, type, false)
        for (var i = 0; i < handlers.length; ++i)
          if (handlers[i] == f) { handlers.splice(i, 1); break; }
      }
    };
  
    var signal = CodeMirror.signal = function(emitter, type /*, values...*/) {
      var handlers = getHandlers(emitter, type, true)
      if (!handlers.length) return;
      var args = Array.prototype.slice.call(arguments, 2);
      for (var i = 0; i < handlers.length; ++i) handlers[i].apply(null, args);
    };
  
    var orphanDelayedCallbacks = null;
  
    // Often, we want to signal events at a point where we are in the
    // middle of some work, but don't want the handler to start calling
    // other methods on the editor, which might be in an inconsistent
    // state or simply not expect any other events to happen.
    // signalLater looks whether there are any handlers, and schedules
    // them to be executed when the last operation ends, or, if no
    // operation is active, when a timeout fires.
    function signalLater(emitter, type /*, values...*/) {
      var arr = getHandlers(emitter, type, false)
      if (!arr.length) return;
      var args = Array.prototype.slice.call(arguments, 2), list;
      if (operationGroup) {
        list = operationGroup.delayedCallbacks;
      } else if (orphanDelayedCallbacks) {
        list = orphanDelayedCallbacks;
      } else {
        list = orphanDelayedCallbacks = [];
        setTimeout(fireOrphanDelayed, 0);
      }
      function bnd(f) {return function(){f.apply(null, args);};};
      for (var i = 0; i < arr.length; ++i)
        list.push(bnd(arr[i]));
    }
  
    function fireOrphanDelayed() {
      var delayed = orphanDelayedCallbacks;
      orphanDelayedCallbacks = null;
      for (var i = 0; i < delayed.length; ++i) delayed[i]();
    }
  
    // The DOM events that CodeMirror handles can be overridden by
    // registering a (non-DOM) handler on the editor for the event name,
    // and preventDefault-ing the event in that handler.
    function signalDOMEvent(cm, e, override) {
      if (typeof e == "string")
        e = {type: e, preventDefault: function() { this.defaultPrevented = true; }};
      signal(cm, override || e.type, cm, e);
      return e_defaultPrevented(e) || e.codemirrorIgnore;
    }
  
    function signalCursorActivity(cm) {
      var arr = cm._handlers && cm._handlers.cursorActivity;
      if (!arr) return;
      var set = cm.curOp.cursorActivityHandlers || (cm.curOp.cursorActivityHandlers = []);
      for (var i = 0; i < arr.length; ++i) if (indexOf(set, arr[i]) == -1)
        set.push(arr[i]);
    }
  
    function hasHandler(emitter, type) {
      return getHandlers(emitter, type).length > 0
    }
  
    // Add on and off methods to a constructor's prototype, to make
    // registering events on such objects more convenient.
    function eventMixin(ctor) {
      ctor.prototype.on = function(type, f) {on(this, type, f);};
      ctor.prototype.off = function(type, f) {off(this, type, f);};
    }
  
    // MISC UTILITIES
  
    // Number of pixels added to scroller and sizer to hide scrollbar
    var scrollerGap = 30;
  
    // Returned or thrown by various protocols to signal 'I'm not
    // handling this'.
    var Pass = CodeMirror.Pass = {toString: function(){return "CodeMirror.Pass";}};
  
    // Reused option objects for setSelection & friends
    var sel_dontScroll = {scroll: false}, sel_mouse = {origin: "*mouse"}, sel_move = {origin: "+move"};
  
    function Delayed() {this.id = null;}
    Delayed.prototype.set = function(ms, f) {
      clearTimeout(this.id);
      this.id = setTimeout(f, ms);
    };
  
    // Counts the column offset in a string, taking tabs into account.
    // Used mostly to find indentation.
    var countColumn = CodeMirror.countColumn = function(string, end, tabSize, startIndex, startValue) {
      if (end == null) {
        end = string.search(/[^\s\u00a0]/);
        if (end == -1) end = string.length;
      }
      for (var i = startIndex || 0, n = startValue || 0;;) {
        var nextTab = string.indexOf("\t", i);
        if (nextTab < 0 || nextTab >= end)
          return n + (end - i);
        n += nextTab - i;
        n += tabSize - (n % tabSize);
        i = nextTab + 1;
      }
    };
  
    // The inverse of countColumn -- find the offset that corresponds to
    // a particular column.
    var findColumn = CodeMirror.findColumn = function(string, goal, tabSize) {
      for (var pos = 0, col = 0;;) {
        var nextTab = string.indexOf("\t", pos);
        if (nextTab == -1) nextTab = string.length;
        var skipped = nextTab - pos;
        if (nextTab == string.length || col + skipped >= goal)
          return pos + Math.min(skipped, goal - col);
        col += nextTab - pos;
        col += tabSize - (col % tabSize);
        pos = nextTab + 1;
        if (col >= goal) return pos;
      }
    }
  
    var spaceStrs = [""];
    function spaceStr(n) {
      while (spaceStrs.length <= n)
        spaceStrs.push(lst(spaceStrs) + " ");
      return spaceStrs[n];
    }
  
    function lst(arr) { return arr[arr.length-1]; }
  
    var selectInput = function(node) { node.select(); };
    if (ios) // Mobile Safari apparently has a bug where select() is broken.
      selectInput = function(node) { node.selectionStart = 0; node.selectionEnd = node.value.length; };
    else if (ie) // Suppress mysterious IE10 errors
      selectInput = function(node) { try { node.select(); } catch(_e) {} };
  
    function indexOf(array, elt) {
      for (var i = 0; i < array.length; ++i)
        if (array[i] == elt) return i;
      return -1;
    }
    function map(array, f) {
      var out = [];
      for (var i = 0; i < array.length; i++) out[i] = f(array[i], i);
      return out;
    }
  
    function nothing() {}
  
    function createObj(base, props) {
      var inst;
      if (Object.create) {
        inst = Object.create(base);
      } else {
        nothing.prototype = base;
        inst = new nothing();
      }
      if (props) copyObj(props, inst);
      return inst;
    };
  
    function copyObj(obj, target, overwrite) {
      if (!target) target = {};
      for (var prop in obj)
        if (obj.hasOwnProperty(prop) && (overwrite !== false || !target.hasOwnProperty(prop)))
          target[prop] = obj[prop];
      return target;
    }
  
    function bind(f) {
      var args = Array.prototype.slice.call(arguments, 1);
      return function(){return f.apply(null, args);};
    }
  
    var nonASCIISingleCaseWordChar = /[\u00df\u0587\u0590-\u05f4\u0600-\u06ff\u3040-\u309f\u30a0-\u30ff\u3400-\u4db5\u4e00-\u9fcc\uac00-\ud7af]/;
    var isWordCharBasic = CodeMirror.isWordChar = function(ch) {
      return /\w/.test(ch) || ch > "\x80" &&
        (ch.toUpperCase() != ch.toLowerCase() || nonASCIISingleCaseWordChar.test(ch));
    };
    function isWordChar(ch, helper) {
      if (!helper) return isWordCharBasic(ch);
      if (helper.source.indexOf("\\w") > -1 && isWordCharBasic(ch)) return true;
      return helper.test(ch);
    }
  
    function isEmpty(obj) {
      for (var n in obj) if (obj.hasOwnProperty(n) && obj[n]) return false;
      return true;
    }
  
    // Extending unicode characters. A series of a non-extending char +
    // any number of extending chars is treated as a single unit as far
    // as editing and measuring is concerned. This is not fully correct,
    // since some scripts/fonts/browsers also treat other configurations
    // of code points as a group.
    var extendingChars = /[\u0300-\u036f\u0483-\u0489\u0591-\u05bd\u05bf\u05c1\u05c2\u05c4\u05c5\u05c7\u0610-\u061a\u064b-\u065e\u0670\u06d6-\u06dc\u06de-\u06e4\u06e7\u06e8\u06ea-\u06ed\u0711\u0730-\u074a\u07a6-\u07b0\u07eb-\u07f3\u0816-\u0819\u081b-\u0823\u0825-\u0827\u0829-\u082d\u0900-\u0902\u093c\u0941-\u0948\u094d\u0951-\u0955\u0962\u0963\u0981\u09bc\u09be\u09c1-\u09c4\u09cd\u09d7\u09e2\u09e3\u0a01\u0a02\u0a3c\u0a41\u0a42\u0a47\u0a48\u0a4b-\u0a4d\u0a51\u0a70\u0a71\u0a75\u0a81\u0a82\u0abc\u0ac1-\u0ac5\u0ac7\u0ac8\u0acd\u0ae2\u0ae3\u0b01\u0b3c\u0b3e\u0b3f\u0b41-\u0b44\u0b4d\u0b56\u0b57\u0b62\u0b63\u0b82\u0bbe\u0bc0\u0bcd\u0bd7\u0c3e-\u0c40\u0c46-\u0c48\u0c4a-\u0c4d\u0c55\u0c56\u0c62\u0c63\u0cbc\u0cbf\u0cc2\u0cc6\u0ccc\u0ccd\u0cd5\u0cd6\u0ce2\u0ce3\u0d3e\u0d41-\u0d44\u0d4d\u0d57\u0d62\u0d63\u0dca\u0dcf\u0dd2-\u0dd4\u0dd6\u0ddf\u0e31\u0e34-\u0e3a\u0e47-\u0e4e\u0eb1\u0eb4-\u0eb9\u0ebb\u0ebc\u0ec8-\u0ecd\u0f18\u0f19\u0f35\u0f37\u0f39\u0f71-\u0f7e\u0f80-\u0f84\u0f86\u0f87\u0f90-\u0f97\u0f99-\u0fbc\u0fc6\u102d-\u1030\u1032-\u1037\u1039\u103a\u103d\u103e\u1058\u1059\u105e-\u1060\u1071-\u1074\u1082\u1085\u1086\u108d\u109d\u135f\u1712-\u1714\u1732-\u1734\u1752\u1753\u1772\u1773\u17b7-\u17bd\u17c6\u17c9-\u17d3\u17dd\u180b-\u180d\u18a9\u1920-\u1922\u1927\u1928\u1932\u1939-\u193b\u1a17\u1a18\u1a56\u1a58-\u1a5e\u1a60\u1a62\u1a65-\u1a6c\u1a73-\u1a7c\u1a7f\u1b00-\u1b03\u1b34\u1b36-\u1b3a\u1b3c\u1b42\u1b6b-\u1b73\u1b80\u1b81\u1ba2-\u1ba5\u1ba8\u1ba9\u1c2c-\u1c33\u1c36\u1c37\u1cd0-\u1cd2\u1cd4-\u1ce0\u1ce2-\u1ce8\u1ced\u1dc0-\u1de6\u1dfd-\u1dff\u200c\u200d\u20d0-\u20f0\u2cef-\u2cf1\u2de0-\u2dff\u302a-\u302f\u3099\u309a\ua66f-\ua672\ua67c\ua67d\ua6f0\ua6f1\ua802\ua806\ua80b\ua825\ua826\ua8c4\ua8e0-\ua8f1\ua926-\ua92d\ua947-\ua951\ua980-\ua982\ua9b3\ua9b6-\ua9b9\ua9bc\uaa29-\uaa2e\uaa31\uaa32\uaa35\uaa36\uaa43\uaa4c\uaab0\uaab2-\uaab4\uaab7\uaab8\uaabe\uaabf\uaac1\uabe5\uabe8\uabed\udc00-\udfff\ufb1e\ufe00-\ufe0f\ufe20-\ufe26\uff9e\uff9f]/;
    function isExtendingChar(ch) { return ch.charCodeAt(0) >= 768 && extendingChars.test(ch); }
  
    // DOM UTILITIES
  
    function elt(tag, content, className, style) {
      var e = document.createElement(tag);
      if (className) e.className = className;
      if (style) e.style.cssText = style;
      if (typeof content == "string") e.appendChild(document.createTextNode(content));
      else if (content) for (var i = 0; i < content.length; ++i) e.appendChild(content[i]);
      return e;
    }
  
    var range;
    if (document.createRange) range = function(node, start, end, endNode) {
      var r = document.createRange();
      r.setEnd(endNode || node, end);
      r.setStart(node, start);
      return r;
    };
    else range = function(node, start, end) {
      var r = document.body.createTextRange();
      try { r.moveToElementText(node.parentNode); }
      catch(e) { return r; }
      r.collapse(true);
      r.moveEnd("character", end);
      r.moveStart("character", start);
      return r;
    };
  
    function removeChildren(e) {
      for (var count = e.childNodes.length; count > 0; --count)
        e.removeChild(e.firstChild);
      return e;
    }
  
    function removeChildrenAndAdd(parent, e) {
      return removeChildren(parent).appendChild(e);
    }
  
    var contains = CodeMirror.contains = function(parent, child) {
      if (child.nodeType == 3) // Android browser always returns false when child is a textnode
        child = child.parentNode;
      if (parent.contains)
        return parent.contains(child);
      do {
        if (child.nodeType == 11) child = child.host;
        if (child == parent) return true;
      } while (child = child.parentNode);
    };
  
    function activeElt() {
      var activeElement = document.activeElement;
      while (activeElement && activeElement.root && activeElement.root.activeElement)
        activeElement = activeElement.root.activeElement;
      return activeElement;
    }
    // Older versions of IE throws unspecified error when touching
    // document.activeElement in some cases (during loading, in iframe)
    if (ie && ie_version < 11) activeElt = function() {
      try { return document.activeElement; }
      catch(e) { return document.body; }
    };
  
    function classTest(cls) { return new RegExp("(^|\\s)" + cls + "(?:$|\\s)\\s*"); }
    var rmClass = CodeMirror.rmClass = function(node, cls) {
      var current = node.className;
      var match = classTest(cls).exec(current);
      if (match) {
        var after = current.slice(match.index + match[0].length);
        node.className = current.slice(0, match.index) + (after ? match[1] + after : "");
      }
    };
    var addClass = CodeMirror.addClass = function(node, cls) {
      var current = node.className;
      if (!classTest(cls).test(current)) node.className += (current ? " " : "") + cls;
    };
    function joinClasses(a, b) {
      var as = a.split(" ");
      for (var i = 0; i < as.length; i++)
        if (as[i] && !classTest(as[i]).test(b)) b += " " + as[i];
      return b;
    }
  
    // WINDOW-WIDE EVENTS
  
    // These must be handled carefully, because naively registering a
    // handler for each editor will cause the editors to never be
    // garbage collected.
  
    function forEachCodeMirror(f) {
      if (!document.body.getElementsByClassName) return;
      var byClass = document.body.getElementsByClassName("CodeMirror");
      for (var i = 0; i < byClass.length; i++) {
        var cm = byClass[i].CodeMirror;
        if (cm) f(cm);
      }
    }
  
    var globalsRegistered = false;
    function ensureGlobalHandlers() {
      if (globalsRegistered) return;
      registerGlobalHandlers();
      globalsRegistered = true;
    }
    function registerGlobalHandlers() {
      // When the window resizes, we need to refresh active editors.
      var resizeTimer;
      on(window, "resize", function() {
        if (resizeTimer == null) resizeTimer = setTimeout(function() {
          resizeTimer = null;
          forEachCodeMirror(onResize);
        }, 100);
      });
      // When the window loses focus, we want to show the editor as blurred
      on(window, "blur", function() {
        forEachCodeMirror(onBlur);
      });
    }
  
    // FEATURE DETECTION
  
    // Detect drag-and-drop
    var dragAndDrop = function() {
      // There is *some* kind of drag-and-drop support in IE6-8, but I
      // couldn't get it to work yet.
      if (ie && ie_version < 9) return false;
      var div = elt('div');
      return "draggable" in div || "dragDrop" in div;
    }();
  
    var zwspSupported;
    function zeroWidthElement(measure) {
      if (zwspSupported == null) {
        var test = elt("span", "\u200b");
        removeChildrenAndAdd(measure, elt("span", [test, document.createTextNode("x")]));
        if (measure.firstChild.offsetHeight != 0)
          zwspSupported = test.offsetWidth <= 1 && test.offsetHeight > 2 && !(ie && ie_version < 8);
      }
      var node = zwspSupported ? elt("span", "\u200b") :
        elt("span", "\u00a0", null, "display: inline-block; width: 1px; margin-right: -1px");
      node.setAttribute("cm-text", "");
      return node;
    }
  
    // Feature-detect IE's crummy client rect reporting for bidi text
    var badBidiRects;
    function hasBadBidiRects(measure) {
      if (badBidiRects != null) return badBidiRects;
      var txt = removeChildrenAndAdd(measure, document.createTextNode("A\u062eA"));
      var r0 = range(txt, 0, 1).getBoundingClientRect();
      if (!r0 || r0.left == r0.right) return false; // Safari returns null in some cases (#2780)
      var r1 = range(txt, 1, 2).getBoundingClientRect();
      return badBidiRects = (r1.right - r0.right < 3);
    }
  
    // See if "".split is the broken IE version, if so, provide an
    // alternative way to split lines.
    var splitLinesAuto = CodeMirror.splitLines = "\n\nb".split(/\n/).length != 3 ? function(string) {
      var pos = 0, result = [], l = string.length;
      while (pos <= l) {
        var nl = string.indexOf("\n", pos);
        if (nl == -1) nl = string.length;
        var line = string.slice(pos, string.charAt(nl - 1) == "\r" ? nl - 1 : nl);
        var rt = line.indexOf("\r");
        if (rt != -1) {
          result.push(line.slice(0, rt));
          pos += rt + 1;
        } else {
          result.push(line);
          pos = nl + 1;
        }
      }
      return result;
    } : function(string){return string.split(/\r\n?|\n/);};
  
    var hasSelection = window.getSelection ? function(te) {
      try { return te.selectionStart != te.selectionEnd; }
      catch(e) { return false; }
    } : function(te) {
      try {var range = te.ownerDocument.selection.createRange();}
      catch(e) {}
      if (!range || range.parentElement() != te) return false;
      return range.compareEndPoints("StartToEnd", range) != 0;
    };
  
    var hasCopyEvent = (function() {
      var e = elt("div");
      if ("oncopy" in e) return true;
      e.setAttribute("oncopy", "return;");
      return typeof e.oncopy == "function";
    })();
  
    var badZoomedRects = null;
    function hasBadZoomedRects(measure) {
      if (badZoomedRects != null) return badZoomedRects;
      var node = removeChildrenAndAdd(measure, elt("span", "x"));
      var normal = node.getBoundingClientRect();
      var fromRange = range(node, 0, 1).getBoundingClientRect();
      return badZoomedRects = Math.abs(normal.left - fromRange.left) > 1;
    }
  
    // KEY NAMES
  
    var keyNames = CodeMirror.keyNames = {
      3: "Enter", 8: "Backspace", 9: "Tab", 13: "Enter", 16: "Shift", 17: "Ctrl", 18: "Alt",
      19: "Pause", 20: "CapsLock", 27: "Esc", 32: "Space", 33: "PageUp", 34: "PageDown", 35: "End",
      36: "Home", 37: "Left", 38: "Up", 39: "Right", 40: "Down", 44: "PrintScrn", 45: "Insert",
      46: "Delete", 59: ";", 61: "=", 91: "Mod", 92: "Mod", 93: "Mod",
      106: "*", 107: "=", 109: "-", 110: ".", 111: "/", 127: "Delete",
      173: "-", 186: ";", 187: "=", 188: ",", 189: "-", 190: ".", 191: "/", 192: "`", 219: "[", 220: "\\",
      221: "]", 222: "'", 63232: "Up", 63233: "Down", 63234: "Left", 63235: "Right", 63272: "Delete",
      63273: "Home", 63275: "End", 63276: "PageUp", 63277: "PageDown", 63302: "Insert"
    };
    (function() {
      // Number keys
      for (var i = 0; i < 10; i++) keyNames[i + 48] = keyNames[i + 96] = String(i);
      // Alphabetic keys
      for (var i = 65; i <= 90; i++) keyNames[i] = String.fromCharCode(i);
      // Function keys
      for (var i = 1; i <= 12; i++) keyNames[i + 111] = keyNames[i + 63235] = "F" + i;
    })();
  
    // BIDI HELPERS
  
    function iterateBidiSections(order, from, to, f) {
      if (!order) return f(from, to, "ltr");
      var found = false;
      for (var i = 0; i < order.length; ++i) {
        var part = order[i];
        if (part.from < to && part.to > from || from == to && part.to == from) {
          f(Math.max(part.from, from), Math.min(part.to, to), part.level == 1 ? "rtl" : "ltr");
          found = true;
        }
      }
      if (!found) f(from, to, "ltr");
    }
  
    function bidiLeft(part) { return part.level % 2 ? part.to : part.from; }
    function bidiRight(part) { return part.level % 2 ? part.from : part.to; }
  
    function lineLeft(line) { var order = getOrder(line); return order ? bidiLeft(order[0]) : 0; }
    function lineRight(line) {
      var order = getOrder(line);
      if (!order) return line.text.length;
      return bidiRight(lst(order));
    }
  
    function lineStart(cm, lineN) {
      var line = getLine(cm.doc, lineN);
      var visual = visualLine(line);
      if (visual != line) lineN = lineNo(visual);
      var order = getOrder(visual);
      var ch = !order ? 0 : order[0].level % 2 ? lineRight(visual) : lineLeft(visual);
      return Pos(lineN, ch);
    }
    function lineEnd(cm, lineN) {
      var merged, line = getLine(cm.doc, lineN);
      while (merged = collapsedSpanAtEnd(line)) {
        line = merged.find(1, true).line;
        lineN = null;
      }
      var order = getOrder(line);
      var ch = !order ? line.text.length : order[0].level % 2 ? lineLeft(line) : lineRight(line);
      return Pos(lineN == null ? lineNo(line) : lineN, ch);
    }
    function lineStartSmart(cm, pos) {
      var start = lineStart(cm, pos.line);
      var line = getLine(cm.doc, start.line);
      var order = getOrder(line);
      if (!order || order[0].level == 0) {
        var firstNonWS = Math.max(0, line.text.search(/\S/));
        var inWS = pos.line == start.line && pos.ch <= firstNonWS && pos.ch;
        return Pos(start.line, inWS ? 0 : firstNonWS);
      }
      return start;
    }
  
    function compareBidiLevel(order, a, b) {
      var linedir = order[0].level;
      if (a == linedir) return true;
      if (b == linedir) return false;
      return a < b;
    }
    var bidiOther;
    function getBidiPartAt(order, pos) {
      bidiOther = null;
      for (var i = 0, found; i < order.length; ++i) {
        var cur = order[i];
        if (cur.from < pos && cur.to > pos) return i;
        if ((cur.from == pos || cur.to == pos)) {
          if (found == null) {
            found = i;
          } else if (compareBidiLevel(order, cur.level, order[found].level)) {
            if (cur.from != cur.to) bidiOther = found;
            return i;
          } else {
            if (cur.from != cur.to) bidiOther = i;
            return found;
          }
        }
      }
      return found;
    }
  
    function moveInLine(line, pos, dir, byUnit) {
      if (!byUnit) return pos + dir;
      do pos += dir;
      while (pos > 0 && isExtendingChar(line.text.charAt(pos)));
      return pos;
    }
  
    // This is needed in order to move 'visually' through bi-directional
    // text -- i.e., pressing left should make the cursor go left, even
    // when in RTL text. The tricky part is the 'jumps', where RTL and
    // LTR text touch each other. This often requires the cursor offset
    // to move more than one unit, in order to visually move one unit.
    function moveVisually(line, start, dir, byUnit) {
      var bidi = getOrder(line);
      if (!bidi) return moveLogically(line, start, dir, byUnit);
      var pos = getBidiPartAt(bidi, start), part = bidi[pos];
      var target = moveInLine(line, start, part.level % 2 ? -dir : dir, byUnit);
  
      for (;;) {
        if (target > part.from && target < part.to) return target;
        if (target == part.from || target == part.to) {
          if (getBidiPartAt(bidi, target) == pos) return target;
          part = bidi[pos += dir];
          return (dir > 0) == part.level % 2 ? part.to : part.from;
        } else {
          part = bidi[pos += dir];
          if (!part) return null;
          if ((dir > 0) == part.level % 2)
            target = moveInLine(line, part.to, -1, byUnit);
          else
            target = moveInLine(line, part.from, 1, byUnit);
        }
      }
    }
  
    function moveLogically(line, start, dir, byUnit) {
      var target = start + dir;
      if (byUnit) while (target > 0 && isExtendingChar(line.text.charAt(target))) target += dir;
      return target < 0 || target > line.text.length ? null : target;
    }
  
    // Bidirectional ordering algorithm
    // See http://unicode.org/reports/tr9/tr9-13.html for the algorithm
    // that this (partially) implements.
  
    // One-char codes used for character types:
    // L (L):   Left-to-Right
    // R (R):   Right-to-Left
    // r (AL):  Right-to-Left Arabic
    // 1 (EN):  European Number
    // + (ES):  European Number Separator
    // % (ET):  European Number Terminator
    // n (AN):  Arabic Number
    // , (CS):  Common Number Separator
    // m (NSM): Non-Spacing Mark
    // b (BN):  Boundary Neutral
    // s (B):   Paragraph Separator
    // t (S):   Segment Separator
    // w (WS):  Whitespace
    // N (ON):  Other Neutrals
  
    // Returns null if characters are ordered as they appear
    // (left-to-right), or an array of sections ({from, to, level}
    // objects) in the order in which they occur visually.
    var bidiOrdering = (function() {
      // Character types for codepoints 0 to 0xff
      var lowTypes = "bbbbbbbbbtstwsbbbbbbbbbbbbbbssstwNN%%%NNNNNN,N,N1111111111NNNNNNNLLLLLLLLLLLLLLLLLLLLLLLLLLNNNNNNLLLLLLLLLLLLLLLLLLLLLLLLLLNNNNbbbbbbsbbbbbbbbbbbbbbbbbbbbbbbbbb,N%%%%NNNNLNNNNN%%11NLNNN1LNNNNNLLLLLLLLLLLLLLLLLLLLLLLNLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLN";
      // Character types for codepoints 0x600 to 0x6ff
      var arabicTypes = "rrrrrrrrrrrr,rNNmmmmmmrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmrrrrrrrnnnnnnnnnn%nnrrrmrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmNmmmm";
      function charType(code) {
        if (code <= 0xf7) return lowTypes.charAt(code);
        else if (0x590 <= code && code <= 0x5f4) return "R";
        else if (0x600 <= code && code <= 0x6ed) return arabicTypes.charAt(code - 0x600);
        else if (0x6ee <= code && code <= 0x8ac) return "r";
        else if (0x2000 <= code && code <= 0x200b) return "w";
        else if (code == 0x200c) return "b";
        else return "L";
      }
  
      var bidiRE = /[\u0590-\u05f4\u0600-\u06ff\u0700-\u08ac]/;
      var isNeutral = /[stwN]/, isStrong = /[LRr]/, countsAsLeft = /[Lb1n]/, countsAsNum = /[1n]/;
      // Browsers seem to always treat the boundaries of block elements as being L.
      var outerType = "L";
  
      function BidiSpan(level, from, to) {
        this.level = level;
        this.from = from; this.to = to;
      }
  
      return function(str) {
        if (!bidiRE.test(str)) return false;
        var len = str.length, types = [];
        for (var i = 0, type; i < len; ++i)
          types.push(type = charType(str.charCodeAt(i)));
  
        // W1. Examine each non-spacing mark (NSM) in the level run, and
        // change the type of the NSM to the type of the previous
        // character. If the NSM is at the start of the level run, it will
        // get the type of sor.
        for (var i = 0, prev = outerType; i < len; ++i) {
          var type = types[i];
          if (type == "m") types[i] = prev;
          else prev = type;
        }
  
        // W2. Search backwards from each instance of a European number
        // until the first strong type (R, L, AL, or sor) is found. If an
        // AL is found, change the type of the European number to Arabic
        // number.
        // W3. Change all ALs to R.
        for (var i = 0, cur = outerType; i < len; ++i) {
          var type = types[i];
          if (type == "1" && cur == "r") types[i] = "n";
          else if (isStrong.test(type)) { cur = type; if (type == "r") types[i] = "R"; }
        }
  
        // W4. A single European separator between two European numbers
        // changes to a European number. A single common separator between
        // two numbers of the same type changes to that type.
        for (var i = 1, prev = types[0]; i < len - 1; ++i) {
          var type = types[i];
          if (type == "+" && prev == "1" && types[i+1] == "1") types[i] = "1";
          else if (type == "," && prev == types[i+1] &&
                   (prev == "1" || prev == "n")) types[i] = prev;
          prev = type;
        }
  
        // W5. A sequence of European terminators adjacent to European
        // numbers changes to all European numbers.
        // W6. Otherwise, separators and terminators change to Other
        // Neutral.
        for (var i = 0; i < len; ++i) {
          var type = types[i];
          if (type == ",") types[i] = "N";
          else if (type == "%") {
            for (var end = i + 1; end < len && types[end] == "%"; ++end) {}
            var replace = (i && types[i-1] == "!") || (end < len && types[end] == "1") ? "1" : "N";
            for (var j = i; j < end; ++j) types[j] = replace;
            i = end - 1;
          }
        }
  
        // W7. Search backwards from each instance of a European number
        // until the first strong type (R, L, or sor) is found. If an L is
        // found, then change the type of the European number to L.
        for (var i = 0, cur = outerType; i < len; ++i) {
          var type = types[i];
          if (cur == "L" && type == "1") types[i] = "L";
          else if (isStrong.test(type)) cur = type;
        }
  
        // N1. A sequence of neutrals takes the direction of the
        // surrounding strong text if the text on both sides has the same
        // direction. European and Arabic numbers act as if they were R in
        // terms of their influence on neutrals. Start-of-level-run (sor)
        // and end-of-level-run (eor) are used at level run boundaries.
        // N2. Any remaining neutrals take the embedding direction.
        for (var i = 0; i < len; ++i) {
          if (isNeutral.test(types[i])) {
            for (var end = i + 1; end < len && isNeutral.test(types[end]); ++end) {}
            var before = (i ? types[i-1] : outerType) == "L";
            var after = (end < len ? types[end] : outerType) == "L";
            var replace = before || after ? "L" : "R";
            for (var j = i; j < end; ++j) types[j] = replace;
            i = end - 1;
          }
        }
  
        // Here we depart from the documented algorithm, in order to avoid
        // building up an actual levels array. Since there are only three
        // levels (0, 1, 2) in an implementation that doesn't take
        // explicit embedding into account, we can build up the order on
        // the fly, without following the level-based algorithm.
        var order = [], m;
        for (var i = 0; i < len;) {
          if (countsAsLeft.test(types[i])) {
            var start = i;
            for (++i; i < len && countsAsLeft.test(types[i]); ++i) {}
            order.push(new BidiSpan(0, start, i));
          } else {
            var pos = i, at = order.length;
            for (++i; i < len && types[i] != "L"; ++i) {}
            for (var j = pos; j < i;) {
              if (countsAsNum.test(types[j])) {
                if (pos < j) order.splice(at, 0, new BidiSpan(1, pos, j));
                var nstart = j;
                for (++j; j < i && countsAsNum.test(types[j]); ++j) {}
                order.splice(at, 0, new BidiSpan(2, nstart, j));
                pos = j;
              } else ++j;
            }
            if (pos < i) order.splice(at, 0, new BidiSpan(1, pos, i));
          }
        }
        if (order[0].level == 1 && (m = str.match(/^\s+/))) {
          order[0].from = m[0].length;
          order.unshift(new BidiSpan(0, 0, m[0].length));
        }
        if (lst(order).level == 1 && (m = str.match(/\s+$/))) {
          lst(order).to -= m[0].length;
          order.push(new BidiSpan(0, len - m[0].length, len));
        }
        if (order[0].level == 2)
          order.unshift(new BidiSpan(1, order[0].to, order[0].to));
        if (order[0].level != lst(order).level)
          order.push(new BidiSpan(order[0].level, len, len));
  
        return order;
      };
    })();
  
    // THE END
  
    CodeMirror.version = "5.13.4";
  
    return CodeMirror;
  });
  