text: // Released under MIT license
  
  // Copyright (c) 2009-2010 Dominic Baggott
  
  // Copyright (c) 2009-2010 Ash Berlin
  
  // Copyright (c) 2011 Christoph Dorn <christoph@christophdorn.com> (http://www.christophdorn.com)
  
  
  
  (function( expose ) {
  
  
  
  /**
  
   *  class Markdown
  
   *
  
   *  Markdown processing in Javascript done right. We have very particular views
  
   *  on what constitutes 'right' which include:
  
   *
  
   *  - produces well-formed HTML (this means that em and strong nesting is
  
   *    important)
  
   *
  
   *  - has an intermediate representation to allow processing of parsed data (We
  
   *    in fact have two, both as [JsonML]: a markdown tree and an HTML tree).
  
   *
  
   *  - is easily extensible to add new dialects without having to rewrite the
  
   *    entire parsing mechanics
  
   *
  
   *  - has a good test suite
  
   *
  
   *  This implementation fulfills all of these (except that the test suite could
  
   *  do with expanding to automatically run all the fixtures from other Markdown
  
   *  implementations.)
  
   *
  
   *  ##### Intermediate Representation
  
   *
  
   *  *TODO* Talk about this :) Its JsonML, but document the node names we use.
  
   *
  
   *  [JsonML]: http://jsonml.org/ "JSON Markup Language"
  
   **/
  
  var Markdown = expose.Markdown = function Markdown(dialect) {
  
    switch (typeof dialect) {
  
      case "undefined":
  
        this.dialect = Markdown.dialects.Gruber;
  
        break;
  
      case "object":
  
        this.dialect = dialect;
  
        break;
  
      default:
  
        if (dialect in Markdown.dialects) {
  
          this.dialect = Markdown.dialects[dialect];
  
        }
  
        else {
  
          throw new Error("Unknown Markdown dialect '" + String(dialect) + "'");
  
        }
  
        break;
  
    }
  
    this.em_state = [];
  
    this.strong_state = [];
  
    this.debug_indent = "";
  
  };
  
  
  
  /**
  
   *  parse( markdown, [dialect] ) -> JsonML
  
   *  - markdown (String): markdown string to parse
  
   *  - dialect (String | Dialect): the dialect to use, defaults to gruber
  
   *
  
   *  Parse `markdown` and return a markdown document as a Markdown.JsonML tree.
  
   **/
  
  expose.parse = function( source, dialect ) {
  
    // dialect will default if undefined
  
    var md = new Markdown( dialect );
  
    return md.toTree( source );
  
  };
  
  
  
  /**
  
   *  toHTML( markdown, [dialect]  ) -> String
  
   *  toHTML( md_tree ) -> String
  
   *  - markdown (String): markdown string to parse
  
   *  - md_tree (Markdown.JsonML): parsed markdown tree
  
   *
  
   *  Take markdown (either as a string or as a JsonML tree) and run it through
  
   *  [[toHTMLTree]] then turn it into a well-formated HTML fragment.
  
   **/
  
  expose.toHTML = function toHTML( source , dialect , options ) {
  
    var input = expose.toHTMLTree( source , dialect , options );
  
  
  
    return expose.renderJsonML( input );
  
  };
  
  
  
  /**
  
   *  toHTMLTree( markdown, [dialect] ) -> JsonML
  
   *  toHTMLTree( md_tree ) -> JsonML
  
   *  - markdown (String): markdown string to parse
  
   *  - dialect (String | Dialect): the dialect to use, defaults to gruber
  
   *  - md_tree (Markdown.JsonML): parsed markdown tree
  
   *
  
   *  Turn markdown into HTML, represented as a JsonML tree. If a string is given
  
   *  to this function, it is first parsed into a markdown tree by calling
  
   *  [[parse]].
  
   **/
  
  expose.toHTMLTree = function toHTMLTree( input, dialect , options ) {
  
    // convert string input to an MD tree
  
    if ( typeof input ==="string" ) input = this.parse( input, dialect );
  
  
  
    // Now convert the MD tree to an HTML tree
  
  
  
    // remove references from the tree
  
    var attrs = extract_attr( input ),
  
        refs = {};
  
  
  
    if ( attrs && attrs.references ) {
  
      refs = attrs.references;
  
    }
  
  
  
    var html = convert_tree_to_html( input, refs , options );
  
    merge_text_nodes( html );
  
    return html;
  
  };
  
  
  
  // For Spidermonkey based engines
  
  function mk_block_toSource() {
  
    return "Markdown.mk_block( " +
  
            uneval(this.toString()) +
  
            ", " +
  
            uneval(this.trailing) +
  
            ", " +
  
            uneval(this.lineNumber) +
  
            " )";
  
  }
  
  
  
  // node
  
  function mk_block_inspect() {
  
    var util = require('util');
  
    return "Markdown.mk_block( " +
  
            util.inspect(this.toString()) +
  
            ", " +
  
            util.inspect(this.trailing) +
  
            ", " +
  
            util.inspect(this.lineNumber) +
  
            " )";
  
  
  
  }
  
  
  
  var mk_block = Markdown.mk_block = function(block, trail, line) {
  
    // Be helpful for default case in tests.
  
    if ( arguments.length == 1 ) trail = "\n\n";
  
  
  
    var s = new String(block);
  
    s.trailing = trail;
  
    // To make it clear its not just a string
  
    s.inspect = mk_block_inspect;
  
    s.toSource = mk_block_toSource;
  
  
  
    if (line != undefined)
  
      s.lineNumber = line;
  
  
  
    return s;
  
  };
  
  
  
  function count_lines( str ) {
  
    var n = 0, i = -1;
  
    while ( ( i = str.indexOf('\n', i+1) ) !== -1) n++;
  
    return n;
  
  }
  
  
  
  // Internal - split source into rough blocks
  
  Markdown.prototype.split_blocks = function splitBlocks( input, startLine ) {
  
    // [\s\S] matches _anything_ (newline or space)
  
    var re = /([\s\S]+?)($|\n(?:\s*\n|$)+)/g,
  
        blocks = [],
  
        m;
  
  
  
    var line_no = 1;
  
  
  
    if ( ( m = /^(\s*\n)/.exec(input) ) != null ) {
  
      // skip (but count) leading blank lines
  
      line_no += count_lines( m[0] );
  
      re.lastIndex = m[0].length;
  
    }
  
  
  
    while ( ( m = re.exec(input) ) !== null ) {
  
      blocks.push( mk_block( m[1], m[2], line_no ) );
  
      line_no += count_lines( m[0] );
  
    }
  
  
  
    return blocks;
  
  };
  
  
  
  /**
  
   *  Markdown#processBlock( block, next ) -> undefined | [ JsonML, ... ]
  
   *  - block (String): the block to process
  
   *  - next (Array): the following blocks
  
   *
  
   * Process `block` and return an array of JsonML nodes representing `block`.
  
   *
  
   * It does this by asking each block level function in the dialect to process
  
   * the block until one can. Succesful handling is indicated by returning an
  
   * array (with zero or more JsonML nodes), failure by a false value.
  
   *
  
   * Blocks handlers are responsible for calling [[Markdown#processInline]]
  
   * themselves as appropriate.
  
   *
  
   * If the blocks were split incorrectly or adjacent blocks need collapsing you
  
   * can adjust `next` in place using shift/splice etc.
  
   *
  
   * If any of this default behaviour is not right for the dialect, you can
  
   * define a `__call__` method on the dialect that will get invoked to handle
  
   * the block processing.
  
   */
  
  Markdown.prototype.processBlock = function processBlock( block, next ) {
  
    var cbs = this.dialect.block,
  
        ord = cbs.__order__;
  
  
  
    if ( "__call__" in cbs ) {
  
      return cbs.__call__.call(this, block, next);
  
    }
  
  
  
    for ( var i = 0; i < ord.length; i++ ) {
  
      //D:this.debug( "Testing", ord[i] );
  
      var res = cbs[ ord[i] ].call( this, block, next );
  
      if ( res ) {
  
        //D:this.debug("  matched");
  
        if ( !isArray(res) || ( res.length > 0 && !( isArray(res[0]) ) ) )
  
          this.debug(ord[i], "didn't return a proper array");
  
        //D:this.debug( "" );
  
        return res;
  
      }
  
    }
  
  
  
    // Uhoh! no match! Should we throw an error?
  
    return [];
  
  };
  
  
  
  Markdown.prototype.processInline = function processInline( block ) {
  
    return this.dialect.inline.__call__.call( this, String( block ) );
  
  };
  
  
  
  /**
  
   *  Markdown#toTree( source ) -> JsonML
  
   *  - source (String): markdown source to parse
  
   *
  
   *  Parse `source` into a JsonML tree representing the markdown document.
  
   **/
  
  // custom_tree means set this.tree to `custom_tree` and restore old value on return
  
  Markdown.prototype.toTree = function toTree( source, custom_root ) {
  
    var blocks = source instanceof Array ? source : this.split_blocks( source );
  
  
  
    // Make tree a member variable so its easier to mess with in extensions
  
    var old_tree = this.tree;
  
    try {
  
      this.tree = custom_root || this.tree || [ "markdown" ];
  
  
  
      blocks:
  
      while ( blocks.length ) {
  
        var b = this.processBlock( blocks.shift(), blocks );
  
  
  
        // Reference blocks and the like won't return any content
  
        if ( !b.length ) continue blocks;
  
  
  
        this.tree.push.apply( this.tree, b );
  
      }
  
      return this.tree;
  
    }
  
    finally {
  
      if ( custom_root ) {
  
        this.tree = old_tree;
  
      }
  
    }
  
  };
  
  
  
  // Noop by default
  
  Markdown.prototype.debug = function () {
  
    var args = Array.prototype.slice.call( arguments);
  
    args.unshift(this.debug_indent);
  
    if (typeof print !== "undefined")
  
        print.apply( print, args );
  
    if (typeof console !== "undefined" && typeof console.log !== "undefined")
  
        console.log.apply( null, args );
  
  }
  
  
  
  Markdown.prototype.loop_re_over_block = function( re, block, cb ) {
  
    // Dont use /g regexps with this
  
    var m,
  
        b = block.valueOf();
  
  
  
    while ( b.length && (m = re.exec(b) ) != null) {
  
      b = b.substr( m[0].length );
  
      cb.call(this, m);
  
    }
  
    return b;
  
  };
  
  
  
  /**
  
   * Markdown.dialects
  
   *
  
   * Namespace of built-in dialects.
  
   **/
  
  Markdown.dialects = {};
  
  
  
  /**
  
   * Markdown.dialects.Gruber
  
   *
  
   * The default dialect that follows the rules set out by John Gruber's
  
   * markdown.pl as closely as possible. Well actually we follow the behaviour of
  
   * that script which in some places is not exactly what the syntax web page
  
   * says.
  
   **/
  
  Markdown.dialects.Gruber = {
  
    block: {
  
      atxHeader: function atxHeader( block, next ) {
  
        var m = block.match( /^(#{1,6})\s*(.*?)\s*#*\s*(?:\n|$)/ );
  
  
  
        if ( !m ) return undefined;
  
  
  
        var header = [ "header", { level: m[ 1 ].length } ];
  
        Array.prototype.push.apply(header, this.processInline(m[ 2 ]));
  
  
  
        if ( m[0].length < block.length )
  
          next.unshift( mk_block( block.substr( m[0].length ), block.trailing, block.lineNumber + 2 ) );
  
  
  
        return [ header ];
  
      },
  
  
  
      setextHeader: function setextHeader( block, next ) {
  
        var m = block.match( /^(.*)\n([-=])\2\2+(?:\n|$)/ );
  
  
  
        if ( !m ) return undefined;
  
  
  
        var level = ( m[ 2 ] === "=" ) ? 1 : 2;
  
        var header = [ "header", { level : level }, m[ 1 ] ];
  
  
  
        if ( m[0].length < block.length )
  
          next.unshift( mk_block( block.substr( m[0].length ), block.trailing, block.lineNumber + 2 ) );
  
  
  
        return [ header ];
  
      },
  
  
  
      code: function code( block, next ) {
  
        // |    Foo
  
        // |bar
  
        // should be a code block followed by a paragraph. Fun
  
        //
  
        // There might also be adjacent code block to merge.
  
  
  
        var ret = [],
  
            re = /^(?: {0,3}\t| {4})(.*)\n?/,
  
            lines;
  
  
  
        // 4 spaces + content
  
        if ( !block.match( re ) ) return undefined;
  
  
  
        block_search:
  
        do {
  
          // Now pull out the rest of the lines
  
          var b = this.loop_re_over_block(
  
                    re, block.valueOf(), function( m ) { ret.push( m[1] ); } );
  
  
  
          if (b.length) {
  
            // Case alluded to in first comment. push it back on as a new block
  
            next.unshift( mk_block(b, block.trailing) );
  
            break block_search;
  
          }
  
          else if (next.length) {
  
            // Check the next block - it might be code too
  
            if ( !next[0].match( re ) ) break block_search;
  
  
  
            // Pull how how many blanks lines follow - minus two to account for .join
  
            ret.push ( block.trailing.replace(/[^\n]/g, '').substring(2) );
  
  
  
            block = next.shift();
  
          }
  
          else {
  
            break block_search;
  
          }
  
        } while (true);
  
  
  
        return [ [ "code_block", ret.join("\n") ] ];
  
      },
  
  
  
      horizRule: function horizRule( block, next ) {
  
        // this needs to find any hr in the block to handle abutting blocks
  
        var m = block.match( /^(?:([\s\S]*?)\n)?[ \t]*([-_*])(?:[ \t]*\2){2,}[ \t]*(?:\n([\s\S]*))?$/ );
  
  
  
        if ( !m ) {
  
          return undefined;
  
        }
  
  
  
        var jsonml = [ [ "hr" ] ];
  
  
  
        // if there's a leading abutting block, process it
  
        if ( m[ 1 ] ) {
  
          jsonml.unshift.apply( jsonml, this.processBlock( m[ 1 ], [] ) );
  
        }
  
  
  
        // if there's a trailing abutting block, stick it into next
  
        if ( m[ 3 ] ) {
  
          next.unshift( mk_block( m[ 3 ] ) );
  
        }
  
  
  
        return jsonml;
  
      },
  
  
  
      // There are two types of lists. Tight and loose. Tight lists have no whitespace
  
      // between the items (and result in text just in the <li>) and loose lists,
  
      // which have an empty line between list items, resulting in (one or more)
  
      // paragraphs inside the <li>.
  
      //
  
      // There are all sorts weird edge cases about the original markdown.pl's
  
      // handling of lists:
  
      //
  
      // * Nested lists are supposed to be indented by four chars per level. But
  
      //   if they aren't, you can get a nested list by indenting by less than
  
      //   four so long as the indent doesn't match an indent of an existing list
  
      //   item in the 'nest stack'.
  
      //
  
      // * The type of the list (bullet or number) is controlled just by the
  
      //    first item at the indent. Subsequent changes are ignored unless they
  
      //    are for nested lists
  
      //
  
      lists: (function( ) {
  
        // Use a closure to hide a few variables.
  
        var any_list = "[*+-]|\\d+\\.",
  
            bullet_list = /[*+-]/,
  
            number_list = /\d+\./,
  
            // Capture leading indent as it matters for determining nested lists.
  
            is_list_re = new RegExp( "^( {0,3})(" + any_list + ")[ \t]+" ),
  
            indent_re = "(?: {0,3}\\t| {4})";
  
  
  
        // TODO: Cache this regexp for certain depths.
  
        // Create a regexp suitable for matching an li for a given stack depth
  
        function regex_for_depth( depth ) {
  
  
  
          return new RegExp(
  
            // m[1] = indent, m[2] = list_type
  
            "(?:^(" + indent_re + "{0," + depth + "} {0,3})(" + any_list + ")\\s+)|" +
  
            // m[3] = cont
  
            "(^" + indent_re + "{0," + (depth-1) + "}[ ]{0,4})"
  
          );
  
        }
  
        function expand_tab( input ) {
  
          return input.replace( / {0,3}\t/g, "    " );
  
        }
  
  
  
        // Add inline content `inline` to `li`. inline comes from processInline
  
        // so is an array of content
  
        function add(li, loose, inline, nl) {
  
          if (loose) {
  
            li.push( [ "para" ].concat(inline) );
  
            return;
  
          }
  
          // Hmmm, should this be any block level element or just paras?
  
          var add_to = li[li.length -1] instanceof Array && li[li.length - 1][0] == "para"
  
                     ? li[li.length -1]
  
                     : li;
  
  
  
          // If there is already some content in this list, add the new line in
  
          if (nl && li.length > 1) inline.unshift(nl);
  
  
  
          for (var i=0; i < inline.length; i++) {
  
            var what = inline[i],
  
                is_str = typeof what == "string";
  
            if (is_str && add_to.length > 1 && typeof add_to[add_to.length-1] == "string" ) {
  
              add_to[ add_to.length-1 ] += what;
  
            }
  
            else {
  
              add_to.push( what );
  
            }
  
          }
  
        }
  
  
  
        // contained means have an indent greater than the current one. On
  
        // *every* line in the block
  
        function get_contained_blocks( depth, blocks ) {
  
  
  
          var re = new RegExp( "^(" + indent_re + "{" + depth + "}.*?\\n?)*$" ),
  
              replace = new RegExp("^" + indent_re + "{" + depth + "}", "gm"),
  
              ret = [];
  
  
  
          while ( blocks.length > 0 ) {
  
            if ( re.exec( blocks[0] ) ) {
  
              var b = blocks.shift(),
  
                  // Now remove that indent
  
                  x = b.replace( replace, "");
  
  
  
              ret.push( mk_block( x, b.trailing, b.lineNumber ) );
  
            }
  
            break;
  
          }
  
          return ret;
  
        }
  
  
  
        // passed to stack.forEach to turn list items up the stack into paras
  
        function paragraphify(s, i, stack) {
  
          var list = s.list;
  
          var last_li = list[list.length-1];
  
  
  
          if (last_li[1] instanceof Array && last_li[1][0] == "para") {
  
            return;
  
          }
  
          if (i+1 == stack.length) {
  
            // Last stack frame
  
            // Keep the same array, but replace the contents
  
            last_li.push( ["para"].concat( last_li.splice(1) ) );
  
          }
  
          else {
  
            var sublist = last_li.pop();
  
            last_li.push( ["para"].concat( last_li.splice(1) ), sublist );
  
          }
  
        }
  
  
  
        // The matcher function
  
        return function( block, next ) {
  
          var m = block.match( is_list_re );
  
          if ( !m ) return undefined;
  
  
  
          function make_list( m ) {
  
            var list = bullet_list.exec( m[2] )
  
                     ? ["bulletlist"]
  
                     : ["numberlist"];
  
  
  
            stack.push( { list: list, indent: m[1] } );
  
            return list;
  
          }
  
  
  
  
  
          var stack = [], // Stack of lists for nesting.
  
              list = make_list( m ),
  
              last_li,
  
              loose = false,
  
              ret = [ stack[0].list ],
  
              i;
  
  
  
          // Loop to search over block looking for inner block elements and loose lists
  
          loose_search:
  
          while( true ) {
  
            // Split into lines preserving new lines at end of line
  
            var lines = block.split( /(?=\n)/ );
  
  
  
            // We have to grab all lines for a li and call processInline on them
  
            // once as there are some inline things that can span lines.
  
            var li_accumulate = "";
  
  
  
            // Loop over the lines in this block looking for tight lists.
  
            tight_search:
  
            for (var line_no=0; line_no < lines.length; line_no++) {
  
              var nl = "",
  
                  l = lines[line_no].replace(/^\n/, function(n) { nl = n; return ""; });
  
  
  
              // TODO: really should cache this
  
              var line_re = regex_for_depth( stack.length );
  
  
  
              m = l.match( line_re );
  
              //print( "line:", uneval(l), "\nline match:", uneval(m) );
  
  
  
              // We have a list item
  
              if ( m[1] !== undefined ) {
  
                // Process the previous list item, if any
  
                if ( li_accumulate.length ) {
  
                  add( last_li, loose, this.processInline( li_accumulate ), nl );
  
                  // Loose mode will have been dealt with. Reset it
  
                  loose = false;
  
                  li_accumulate = "";
  
                }
  
  
  
                m[1] = expand_tab( m[1] );
  
                var wanted_depth = Math.floor(m[1].length/4)+1;
  
                //print( "want:", wanted_depth, "stack:", stack.length);
  
                if ( wanted_depth > stack.length ) {
  
                  // Deep enough for a nested list outright
  
                  //print ( "new nested list" );
  
                  list = make_list( m );
  
                  last_li.push( list );
  
                  last_li = list[1] = [ "listitem" ];
  
                }
  
                else {
  
                  // We aren't deep enough to be strictly a new level. This is
  
                  // where Md.pl goes nuts. If the indent matches a level in the
  
                  // stack, put it there, else put it one deeper then the
  
                  // wanted_depth deserves.
  
                  var found = false;
  
                  for (i = 0; i < stack.length; i++) {
  
                    if ( stack[ i ].indent != m[1] ) continue;
  
                    list = stack[ i ].list;
  
                    stack.splice( i+1 );
  
                    found = true;
  
                    break;
  
                  }
  
  
  
                  if (!found) {
  
                    //print("not found. l:", uneval(l));
  
                    wanted_depth++;
  
                    if (wanted_depth <= stack.length) {
  
                      stack.splice(wanted_depth);
  
                      //print("Desired depth now", wanted_depth, "stack:", stack.length);
  
                      list = stack[wanted_depth-1].list;
  
                      //print("list:", uneval(list) );
  
                    }
  
                    else {
  
                      //print ("made new stack for messy indent");
  
                      list = make_list(m);
  
                      last_li.push(list);
  
                    }
  
                  }
  
  
  
                  //print( uneval(list), "last", list === stack[stack.length-1].list );
  
                  last_li = [ "listitem" ];
  
                  list.push(last_li);
  
                } // end depth of shenegains
  
                nl = "";
  
              }
  
  
  
              // Add content
  
              if (l.length > m[0].length) {
  
                li_accumulate += nl + l.substr( m[0].length );
  
              }
  
            } // tight_search
  
  
  
            if ( li_accumulate.length ) {
  
              add( last_li, loose, this.processInline( li_accumulate ), nl );
  
              // Loose mode will have been dealt with. Reset it
  
              loose = false;
  
              li_accumulate = "";
  
            }
  
  
  
            // Look at the next block - we might have a loose list. Or an extra
  
            // paragraph for the current li
  
            var contained = get_contained_blocks( stack.length, next );
  
  
  
            // Deal with code blocks or properly nested lists
  
            if (contained.length > 0) {
  
              // Make sure all listitems up the stack are paragraphs
  
              forEach( stack, paragraphify, this);
  
  
  
              last_li.push.apply( last_li, this.toTree( contained, [] ) );
  
            }
  
  
  
            var next_block = next[0] && next[0].valueOf() || "";
  
  
  
            if ( next_block.match(is_list_re) || next_block.match( /^ / ) ) {
  
              block = next.shift();
  
  
  
              // Check for an HR following a list: features/lists/hr_abutting
  
              var hr = this.dialect.block.horizRule( block, next );
  
  
  
              if (hr) {
  
                ret.push.apply(ret, hr);
  
                break;
  
              }
  
  
  
              // Make sure all listitems up the stack are paragraphs
  
              forEach( stack, paragraphify, this);
  
  
  
              loose = true;
  
              continue loose_search;
  
            }
  
            break;
  
          } // loose_search
  
  
  
          return ret;
  
        };
  
      })(),
  
  
  
      blockquote: function blockquote( block, next ) {
  
        if ( !block.match( /^>/m ) )
  
          return undefined;
  
  
  
        var jsonml = [];
  
  
  
        // separate out the leading abutting block, if any
  
        if ( block[ 0 ] != ">" ) {
  
          var lines = block.split( /\n/ ),
  
              prev = [];
  
  
  
          // keep shifting lines until you find a crotchet
  
          while ( lines.length && lines[ 0 ][ 0 ] != ">" ) {
  
              prev.push( lines.shift() );
  
          }
  
  
  
          // reassemble!
  
          block = lines.join( "\n" );
  
          jsonml.push.apply( jsonml, this.processBlock( prev.join( "\n" ), [] ) );
  
        }
  
  
  
        // if the next block is also a blockquote merge it in
  
        while ( next.length && next[ 0 ][ 0 ] == ">" ) {
  
          var b = next.shift();
  
          block = new String(block + block.trailing + b);
  
          block.trailing = b.trailing;
  
        }
  
  
  
        // Strip off the leading "> " and re-process as a block.
  
        var input = block.replace( /^> ?/gm, '' ),
  
            old_tree = this.tree;
  
        jsonml.push( this.toTree( input, [ "blockquote" ] ) );
  
  
  
        return jsonml;
  
      },
  
  
  
      referenceDefn: function referenceDefn( block, next) {
  
        var re = /^\s*\[(.*?)\]:\s*(\S+)(?:\s+(?:(['"])(.*?)\3|\((.*?)\)))?\n?/;
  
        // interesting matches are [ , ref_id, url, , title, title ]
  
  
  
        if ( !block.match(re) )
  
          return undefined;
  
  
  
        // make an attribute node if it doesn't exist
  
        if ( !extract_attr( this.tree ) ) {
  
          this.tree.splice( 1, 0, {} );
  
        }
  
  
  
        var attrs = extract_attr( this.tree );
  
  
  
        // make a references hash if it doesn't exist
  
        if ( attrs.references === undefined ) {
  
          attrs.references = {};
  
        }
  
  
  
        var b = this.loop_re_over_block(re, block, function( m ) {
  
  
  
          if ( m[2] && m[2][0] == '<' && m[2][m[2].length-1] == '>' )
  
            m[2] = m[2].substring( 1, m[2].length - 1 );
  
  
  
          var ref = attrs.references[ m[1].toLowerCase() ] = {
  
            href: m[2]
  
          };
  
  
  
          if (m[4] !== undefined)
  
            ref.title = m[4];
  
          else if (m[5] !== undefined)
  
            ref.title = m[5];
  
  
  
        } );
  
  
  
        if (b.length)
  
          next.unshift( mk_block( b, block.trailing ) );
  
  
  
        return [];
  
      },
  
  
  
      para: function para( block, next ) {
  
        // everything's a para!
  
        return [ ["para"].concat( this.processInline( block ) ) ];
  
      }
  
    }
  
  };
  
  
  
  Markdown.dialects.Gruber.inline = {
  
  
  
      __oneElement__: function oneElement( text, patterns_or_re, previous_nodes ) {
  
        var m,
  
            res,
  
            lastIndex = 0;
  
  
  
        patterns_or_re = patterns_or_re || this.dialect.inline.__patterns__;
  
        var re = new RegExp( "([\\s\\S]*?)(" + (patterns_or_re.source || patterns_or_re) + ")" );
  
  
  
        m = re.exec( text );
  
        if (!m) {
  
          // Just boring text
  
          return [ text.length, text ];
  
        }
  
        else if ( m[1] ) {
  
          // Some un-interesting text matched. Return that first
  
          return [ m[1].length, m[1] ];
  
        }
  
  
  
        var res;
  
        if ( m[2] in this.dialect.inline ) {
  
          res = this.dialect.inline[ m[2] ].call(
  
                    this,
  
                    text.substr( m.index ), m, previous_nodes || [] );
  
        }
  
        // Default for now to make dev easier. just slurp special and output it.
  
        res = res || [ m[2].length, m[2] ];
  
        return res;
  
      },
  
  
  
      __call__: function inline( text, patterns ) {
  
  
  
        var out = [],
  
            res;
  
  
  
        function add(x) {
  
          //D:self.debug("  adding output", uneval(x));
  
          if (typeof x == "string" && typeof out[out.length-1] == "string")
  
            out[ out.length-1 ] += x;
  
          else
  
            out.push(x);
  
        }
  
  
  
        while ( text.length > 0 ) {
  
          res = this.dialect.inline.__oneElement__.call(this, text, patterns, out );
  
          text = text.substr( res.shift() );
  
          forEach(res, add )
  
        }
  
  
  
        return out;
  
      },
  
  
  
      // These characters are intersting elsewhere, so have rules for them so that
  
      // chunks of plain text blocks don't include them
  
      "]": function () {},
  
      "}": function () {},
  
  
  
      "\\": function escaped( text ) {
  
        // [ length of input processed, node/children to add... ]
  
        // Only esacape: \ ` * _ { } [ ] ( ) # * + - . !
  
        if ( text.match( /^\\[\\`\*_{}\[\]()#\+.!\-]/ ) )
  
          return [ 2, text[1] ];
  
        else
  
          // Not an esacpe
  
          return [ 1, "\\" ];
  
      },
  
  
  
      "![": function image( text ) {
  
  
  
        // Unlike images, alt text is plain text only. no other elements are
  
        // allowed in there
  
  
  
        // ![Alt text](/path/to/img.jpg "Optional title")
  
        //      1          2            3       4         <--- captures
  
        var m = text.match( /^!\[(.*?)\][ \t]*\([ \t]*(\S*)(?:[ \t]+(["'])(.*?)\3)?[ \t]*\)/ );
  
  
  
        if ( m ) {
  
          if ( m[2] && m[2][0] == '<' && m[2][m[2].length-1] == '>' )
  
            m[2] = m[2].substring( 1, m[2].length - 1 );
  
  
  
          m[2] = this.dialect.inline.__call__.call( this, m[2], /\\/ )[0];
  
  
  
          var attrs = { alt: m[1], href: m[2] || "" };
  
          if ( m[4] !== undefined)
  
            attrs.title = m[4];
  
  
  
          return [ m[0].length, [ "img", attrs ] ];
  
        }
  
  
  
        // ![Alt text][id]
  
        m = text.match( /^!\[(.*?)\][ \t]*\[(.*?)\]/ );
  
  
  
        if ( m ) {
  
          // We can't check if the reference is known here as it likely wont be
  
          // found till after. Check it in md tree->hmtl tree conversion
  
          return [ m[0].length, [ "img_ref", { alt: m[1], ref: m[2].toLowerCase(), original: m[0] } ] ];
  
        }
  
  
  
        // Just consume the '!['
  
        return [ 2, "![" ];
  
      },
  
  
  
      "[": function link( text ) {
  
  
  
        var orig = String(text);
  
        // Inline content is possible inside `link text`
  
        var res = Markdown.DialectHelpers.inline_until_char.call( this, text.substr(1), ']' );
  
  
  
        // No closing ']' found. Just consume the [
  
        if ( !res ) return [ 1, '[' ];
  
  
  
        var consumed = 1 + res[ 0 ],
  
            children = res[ 1 ],
  
            link,
  
            attrs;
  
  
  
        // At this point the first [...] has been parsed. See what follows to find
  
        // out which kind of link we are (reference or direct url)
  
        text = text.substr( consumed );
  
  
  
        // [link text](/path/to/img.jpg "Optional title")
  
        //                 1            2       3         <--- captures
  
        // This will capture up to the last paren in the block. We then pull
  
        // back based on if there a matching ones in the url
  
        //    ([here](/url/(test))
  
        // The parens have to be balanced
  
        var m = text.match( /^\s*\([ \t]*(\S+)(?:[ \t]+(["'])(.*?)\2)?[ \t]*\)/ );
  
        if ( m ) {
  
          var url = m[1];
  
          consumed += m[0].length;
  
  
  
          if ( url && url[0] == '<' && url[url.length-1] == '>' )
  
            url = url.substring( 1, url.length - 1 );
  
  
  
          // If there is a title we don't have to worry about parens in the url
  
          if ( !m[3] ) {
  
            var open_parens = 1; // One open that isn't in the capture
  
            for (var len = 0; len < url.length; len++) {
  
              switch ( url[len] ) {
  
              case '(':
  
                open_parens++;
  
                break;
  
              case ')':
  
                if ( --open_parens == 0) {
  
                  consumed -= url.length - len;
  
                  url = url.substring(0, len);
  
                }
  
                break;
  
              }
  
            }
  
          }
  
  
  
          // Process escapes only
  
          url = this.dialect.inline.__call__.call( this, url, /\\/ )[0];
  
  
  
          attrs = { href: url || "" };
  
          if ( m[3] !== undefined)
  
            attrs.title = m[3];
  
  
  
          link = [ "link", attrs ].concat( children );
  
          return [ consumed, link ];
  
        }
  
  
  
        // [Alt text][id]
  
        // [Alt text] [id]
  
        m = text.match( /^\s*\[(.*?)\]/ );
  
  
  
        if ( m ) {
  
  
  
          consumed += m[ 0 ].length;
  
  
  
          // [links][] uses links as its reference
  
          attrs = { ref: ( m[ 1 ] || String(children) ).toLowerCase(),  original: orig.substr( 0, consumed ) };
  
  
  
          link = [ "link_ref", attrs ].concat( children );
  
  
  
          // We can't check if the reference is known here as it likely wont be
  
          // found till after. Check it in md tree->hmtl tree conversion.
  
          // Store the original so that conversion can revert if the ref isn't found.
  
          return [ consumed, link ];
  
        }
  
  
  
        // [id]
  
        // Only if id is plain (no formatting.)
  
        if ( children.length == 1 && typeof children[0] == "string" ) {
  
  
  
          attrs = { ref: children[0].toLowerCase(),  original: orig.substr( 0, consumed ) };
  
          link = [ "link_ref", attrs, children[0] ];
  
          return [ consumed, link ];
  
        }
  
  
  
        // Just consume the '['
  
        return [ 1, "[" ];
  
      },
  
  
  
  
  
      "<": function autoLink( text ) {
  
        var m;
  
  
  
        if ( ( m = text.match( /^<(?:((https?|ftp|mailto):[^>]+)|(.*?@.*?\.[a-zA-Z]+))>/ ) ) != null ) {
  
          if ( m[3] ) {
  
            return [ m[0].length, [ "link", { href: "mailto:" + m[3] }, m[3] ] ];
  
  
  
          }
  
          else if ( m[2] == "mailto" ) {
  
            return [ m[0].length, [ "link", { href: m[1] }, m[1].substr("mailto:".length ) ] ];
  
          }
  
          else
  
            return [ m[0].length, [ "link", { href: m[1] }, m[1] ] ];
  
        }
  
  
  
        return [ 1, "<" ];
  
      },
  
  
  
      "`": function inlineCode( text ) {
  
        // Inline code block. as many backticks as you like to start it
  
        // Always skip over the opening ticks.
  
        var m = text.match( /(`+)(([\s\S]*?)\1)/ );
  
  
  
        if ( m && m[2] )
  
          return [ m[1].length + m[2].length, [ "inlinecode", m[3] ] ];
  
        else {
  
          // TODO: No matching end code found - warn!
  
          return [ 1, "`" ];
  
        }
  
      },
  
  
  
      "  \n": function lineBreak( text ) {
  
        return [ 3, [ "linebreak" ] ];
  
      }
  
  
  
  };
  
  
  
  // Meta Helper/generator method for em and strong handling
  
  function strong_em( tag, md ) {
  
  
  
    var state_slot = tag + "_state",
  
        other_slot = tag == "strong" ? "em_state" : "strong_state";
  
  
  
    function CloseTag(len) {
  
      this.len_after = len;
  
      this.name = "close_" + md;
  
    }
  
  
  
    return function ( text, orig_match ) {
  
  
  
      if (this[state_slot][0] == md) {
  
        // Most recent em is of this type
  
        //D:this.debug("closing", md);
  
        this[state_slot].shift();
  
  
  
        // "Consume" everything to go back to the recrusion in the else-block below
  
        return[ text.length, new CloseTag(text.length-md.length) ];
  
      }
  
      else {
  
        // Store a clone of the em/strong states
  
        var other = this[other_slot].slice(),
  
            state = this[state_slot].slice();
  
  
  
        this[state_slot].unshift(md);
  
  
  
        //D:this.debug_indent += "  ";
  
  
  
        // Recurse
  
        var res = this.processInline( text.substr( md.length ) );
  
        //D:this.debug_indent = this.debug_indent.substr(2);
  
  
  
        var last = res[res.length - 1];
  
  
  
        //D:this.debug("processInline from", tag + ": ", uneval( res ) );
  
  
  
        var check = this[state_slot].shift();
  
        if (last instanceof CloseTag) {
  
          res.pop();
  
          // We matched! Huzzah.
  
          var consumed = text.length - last.len_after;
  
          return [ consumed, [ tag ].concat(res) ];
  
        }
  
        else {
  
          // Restore the state of the other kind. We might have mistakenly closed it.
  
          this[other_slot] = other;
  
          this[state_slot] = state;
  
  
  
          // We can't reuse the processed result as it could have wrong parsing contexts in it.
  
          return [ md.length, md ];
  
        }
  
      }
  
    }; // End returned function
  
  }
  
  
  
  Markdown.dialects.Gruber.inline["**"] = strong_em("strong", "**");
  
  Markdown.dialects.Gruber.inline["__"] = strong_em("strong", "__");
  
  Markdown.dialects.Gruber.inline["*"]  = strong_em("em", "*");
  
  Markdown.dialects.Gruber.inline["_"]  = strong_em("em", "_");
  
  
  
  
  
  // Build default order from insertion order.
  
  Markdown.buildBlockOrder = function(d) {
  
    var ord = [];
  
    for ( var i in d ) {
  
      if ( i == "__order__" || i == "__call__" ) continue;
  
      ord.push( i );
  
    }
  
    d.__order__ = ord;
  
  };
  
  
  
  // Build patterns for inline matcher
  
  Markdown.buildInlinePatterns = function(d) {
  
    var patterns = [];
  
  
  
    for ( var i in d ) {
  
      // __foo__ is reserved and not a pattern
  
      if ( i.match( /^__.*__$/) ) continue;
  
      var l = i.replace( /([\\.*+?|()\[\]{}])/g, "\\$1" )
  
               .replace( /\n/, "\\n" );
  
      patterns.push( i.length == 1 ? l : "(?:" + l + ")" );
  
    }
  
  
  
    patterns = patterns.join("|");
  
    d.__patterns__ = patterns;
  
    //print("patterns:", uneval( patterns ) );
  
  
  
    var fn = d.__call__;
  
    d.__call__ = function(text, pattern) {
  
      if (pattern != undefined) {
  
        return fn.call(this, text, pattern);
  
      }
  
      else
  
      {
  
        return fn.call(this, text, patterns);
  
      }
  
    };
  
  };
  
  
  
  Markdown.DialectHelpers = {};
  
  Markdown.DialectHelpers.inline_until_char = function( text, want ) {
  
    var consumed = 0,
  
        nodes = [];
  
  
  
    while ( true ) {
  
      if ( text[ consumed ] == want ) {
  
        // Found the character we were looking for
  
        consumed++;
  
        return [ consumed, nodes ];
  
      }
  
  
  
      if ( consumed >= text.length ) {
  
        // No closing char found. Abort.
  
        return null;
  
      }
  
  
  
      var res = this.dialect.inline.__oneElement__.call(this, text.substr( consumed ) );
  
      consumed += res[ 0 ];
  
      // Add any returned nodes.
  
      nodes.push.apply( nodes, res.slice( 1 ) );
  
    }
  
  }
  
  
  
  // Helper function to make sub-classing a dialect easier
  
  Markdown.subclassDialect = function( d ) {
  
    function Block() {}
  
    Block.prototype = d.block;
  
    function Inline() {}
  
    Inline.prototype = d.inline;
  
  
  
    return { block: new Block(), inline: new Inline() };
  
  };
  
  
  
  Markdown.buildBlockOrder ( Markdown.dialects.Gruber.block );
  
  Markdown.buildInlinePatterns( Markdown.dialects.Gruber.inline );
  
  
  
  Markdown.dialects.Maruku = Markdown.subclassDialect( Markdown.dialects.Gruber );
  
  
  
  Markdown.dialects.Maruku.processMetaHash = function processMetaHash( meta_string ) {
  
    var meta = split_meta_hash( meta_string ),
  
        attr = {};
  
  
  
    for ( var i = 0; i < meta.length; ++i ) {
  
      // id: #foo
  
      if ( /^#/.test( meta[ i ] ) ) {
  
        attr.id = meta[ i ].substring( 1 );
  
      }
  
      // class: .foo
  
      else if ( /^\./.test( meta[ i ] ) ) {
  
        // if class already exists, append the new one
  
        if ( attr['class'] ) {
  
          attr['class'] = attr['class'] + meta[ i ].replace( /./, " " );
  
        }
  
        else {
  
          attr['class'] = meta[ i ].substring( 1 );
  
        }
  
      }
  
      // attribute: foo=bar
  
      else if ( /\=/.test( meta[ i ] ) ) {
  
        var s = meta[ i ].split( /\=/ );
  
        attr[ s[ 0 ] ] = s[ 1 ];
  
      }
  
    }
  
  
  
    return attr;
  
  }
  
  
  
  function split_meta_hash( meta_string ) {
  
    var meta = meta_string.split( "" ),
  
        parts = [ "" ],
  
        in_quotes = false;
  
  
  
    while ( meta.length ) {
  
      var letter = meta.shift();
  
      switch ( letter ) {
  
        case " " :
  
          // if we're in a quoted section, keep it
  
          if ( in_quotes ) {
  
            parts[ parts.length - 1 ] += letter;
  
          }
  
          // otherwise make a new part
  
          else {
  
            parts.push( "" );
  
          }
  
          break;
  
        case "'" :
  
        case '"' :
  
          // reverse the quotes and move straight on
  
          in_quotes = !in_quotes;
  
          break;
  
        case "\\" :
  
          // shift off the next letter to be used straight away.
  
          // it was escaped so we'll keep it whatever it is
  
          letter = meta.shift();
  
        default :
  
          parts[ parts.length - 1 ] += letter;
  
          break;
  
      }
  
    }
  
  
  
    return parts;
  
  }
  
  
  
  Markdown.dialects.Maruku.block.document_meta = function document_meta( block, next ) {
  
    // we're only interested in the first block
  
    if ( block.lineNumber > 1 ) return undefined;
  
  
  
    // document_meta blocks consist of one or more lines of `Key: Value\n`
  
    if ( ! block.match( /^(?:\w+:.*\n)*\w+:.*$/ ) ) return undefined;
  
  
  
    // make an attribute node if it doesn't exist
  
    if ( !extract_attr( this.tree ) ) {
  
      this.tree.splice( 1, 0, {} );
  
    }
  
  
  
    var pairs = block.split( /\n/ );
  
    for ( p in pairs ) {
  
      var m = pairs[ p ].match( /(\w+):\s*(.*)$/ ),
  
          key = m[ 1 ].toLowerCase(),
  
          value = m[ 2 ];
  
  
  
      this.tree[ 1 ][ key ] = value;
  
    }
  
  
  
    // document_meta produces no content!
  
    return [];
  
  };
  
  
  
  Markdown.dialects.Maruku.block.block_meta = function block_meta( block, next ) {
  
    // check if the last line of the block is an meta hash
  
    var m = block.match( /(^|\n) {0,3}\{:\s*((?:\\\}|[^\}])*)\s*\}$/ );
  
    if ( !m ) return undefined;
  
  
  
    // process the meta hash
  
    var attr = this.dialect.processMetaHash( m[ 2 ] );
  
  
  
    var hash;
  
  
  
    // if we matched ^ then we need to apply meta to the previous block
  
    if ( m[ 1 ] === "" ) {
  
      var node = this.tree[ this.tree.length - 1 ];
  
      hash = extract_attr( node );
  
  
  
      // if the node is a string (rather than JsonML), bail
  
      if ( typeof node === "string" ) return undefined;
  
  
  
      // create the attribute hash if it doesn't exist
  
      if ( !hash ) {
  
        hash = {};
  
        node.splice( 1, 0, hash );
  
      }
  
  
  
      // add the attributes in
  
      for ( a in attr ) {
  
        hash[ a ] = attr[ a ];
  
      }
  
  
  
      // return nothing so the meta hash is removed
  
      return [];
  
    }
  
  
  
    // pull the meta hash off the block and process what's left
  
    var b = block.replace( /\n.*$/, "" ),
  
        result = this.processBlock( b, [] );
  
  
  
    // get or make the attributes hash
  
    hash = extract_attr( result[ 0 ] );
  
    if ( !hash ) {
  
      hash = {};
  
      result[ 0 ].splice( 1, 0, hash );
  
    }
  
  
  
    // attach the attributes to the block
  
    for ( a in attr ) {
  
      hash[ a ] = attr[ a ];
  
    }
  
  
  
    return result;
  
  };
  
  
  
  Markdown.dialects.Maruku.block.definition_list = function definition_list( block, next ) {
  
    // one or more terms followed by one or more definitions, in a single block
  
    var tight = /^((?:[^\s:].*\n)+):\s+([\s\S]+)$/,
  
        list = [ "dl" ],
  
        i;
  
  
  
    // see if we're dealing with a tight or loose block
  
    if ( ( m = block.match( tight ) ) ) {
  
      // pull subsequent tight DL blocks out of `next`
  
      var blocks = [ block ];
  
      while ( next.length && tight.exec( next[ 0 ] ) ) {
  
        blocks.push( next.shift() );
  
      }
  
  
  
      for ( var b = 0; b < blocks.length; ++b ) {
  
        var m = blocks[ b ].match( tight ),
  
            terms = m[ 1 ].replace( /\n$/, "" ).split( /\n/ ),
  
            defns = m[ 2 ].split( /\n:\s+/ );
  
  
  
        // print( uneval( m ) );
  
  
  
        for ( i = 0; i < terms.length; ++i ) {
  
          list.push( [ "dt", terms[ i ] ] );
  
        }
  
  
  
        for ( i = 0; i < defns.length; ++i ) {
  
          // run inline processing over the definition
  
          list.push( [ "dd" ].concat( this.processInline( defns[ i ].replace( /(\n)\s+/, "$1" ) ) ) );
  
        }
  
      }
  
    }
  
    else {
  
      return undefined;
  
    }
  
  
  
    return [ list ];
  
  };
  
  
  
  Markdown.dialects.Maruku.inline[ "{:" ] = function inline_meta( text, matches, out ) {
  
    if ( !out.length ) {
  
      return [ 2, "{:" ];
  
    }
  
  
  
    // get the preceeding element
  
    var before = out[ out.length - 1 ];
  
  
  
    if ( typeof before === "string" ) {
  
      return [ 2, "{:" ];
  
    }
  
  
  
    // match a meta hash
  
    var m = text.match( /^\{:\s*((?:\\\}|[^\}])*)\s*\}/ );
  
  
  
    // no match, false alarm
  
    if ( !m ) {
  
      return [ 2, "{:" ];
  
    }
  
  
  
    // attach the attributes to the preceeding element
  
    var meta = this.dialect.processMetaHash( m[ 1 ] ),
  
        attr = extract_attr( before );
  
  
  
    if ( !attr ) {
  
      attr = {};
  
      before.splice( 1, 0, attr );
  
    }
  
  
  
    for ( var k in meta ) {
  
      attr[ k ] = meta[ k ];
  
    }
  
  
  
    // cut out the string and replace it with nothing
  
    return [ m[ 0 ].length, "" ];
  
  };
  
  
  
  Markdown.buildBlockOrder ( Markdown.dialects.Maruku.block );
  
  Markdown.buildInlinePatterns( Markdown.dialects.Maruku.inline );
  
  
  
  var isArray = Array.isArray || function(obj) {
  
    return Object.prototype.toString.call(obj) == '[object Array]';
  
  };
  
  
  
  var forEach;
  
  // Don't mess with Array.prototype. Its not friendly
  
  if ( Array.prototype.forEach ) {
  
    forEach = function( arr, cb, thisp ) {
  
      return arr.forEach( cb, thisp );
  
    };
  
  }
  
  else {
  
    forEach = function(arr, cb, thisp) {
  
      for (var i = 0; i < arr.length; i++) {
  
        cb.call(thisp || arr, arr[i], i, arr);
  
      }
  
    }
  
  }
  
  
  
  function extract_attr( jsonml ) {
  
    return isArray(jsonml)
  
        && jsonml.length > 1
  
        && typeof jsonml[ 1 ] === "object"
  
        && !( isArray(jsonml[ 1 ]) )
  
        ? jsonml[ 1 ]
  
        : undefined;
  
  }
  
  
  
  
  
  
  
  /**
  
   *  renderJsonML( jsonml[, options] ) -> String
  
   *  - jsonml (Array): JsonML array to render to XML
  
   *  - options (Object): options
  
   *
  
   *  Converts the given JsonML into well-formed XML.
  
   *
  
   *  The options currently understood are:
  
   *
  
   *  - root (Boolean): wether or not the root node should be included in the
  
   *    output, or just its children. The default `false` is to not include the
  
   *    root itself.
  
   */
  
  expose.renderJsonML = function( jsonml, options ) {
  
    options = options || {};
  
    // include the root element in the rendered output?
  
    options.root = options.root || false;
  
  
  
    var content = [];
  
  
  
    if ( options.root ) {
  
      content.push( render_tree( jsonml ) );
  
    }
  
    else {
  
      jsonml.shift(); // get rid of the tag
  
      if ( jsonml.length && typeof jsonml[ 0 ] === "object" && !( jsonml[ 0 ] instanceof Array ) ) {
  
        jsonml.shift(); // get rid of the attributes
  
      }
  
  
  
      while ( jsonml.length ) {
  
        content.push( render_tree( jsonml.shift() ) );
  
      }
  
    }
  
  
  
    return content.join( "\n\n" );
  
  };
  
  
  
  function escapeHTML( text ) {
  
    return text.replace( /&/g, "&amp;" )
  
               .replace( /</g, "&lt;" )
  
               .replace( />/g, "&gt;" )
  
               .replace( /"/g, "&quot;" )
  
               .replace( /'/g, "&#39;" );
  
  }
  
  
  
  function render_tree( jsonml ) {
  
    // basic case
  
    if ( typeof jsonml === "string" ) {
  
      return escapeHTML( jsonml );
  
    }
  
  
  
    var tag = jsonml.shift(),
  
        attributes = {},
  
        content = [];
  
  
  
    if ( jsonml.length && typeof jsonml[ 0 ] === "object" && !( jsonml[ 0 ] instanceof Array ) ) {
  
      attributes = jsonml.shift();
  
    }
  
  
  
    while ( jsonml.length ) {
  
      content.push( arguments.callee( jsonml.shift() ) );
  
    }
  
  
  
    var tag_attrs = "";
  
    for ( var a in attributes ) {
  
      tag_attrs += " " + a + '="' + escapeHTML( attributes[ a ] ) + '"';
  
    }
  
  
  
    // be careful about adding whitespace here for inline elements
  
    if ( tag == "img" || tag == "br" || tag == "hr" ) {
  
      return "<"+ tag + tag_attrs + "/>";
  
    }
  
    else {
  
      return "<"+ tag + tag_attrs + ">" + content.join( "" ) + "</" + tag + ">";
  
    }
  
  }
  
  
  
  function convert_tree_to_html( tree, references, options ) {
  
    var i;
  
    options = options || {};
  
  
  
    // shallow clone
  
    var jsonml = tree.slice( 0 );
  
  
  
    if (typeof options.preprocessTreeNode === "function") {
  
        jsonml = options.preprocessTreeNode(jsonml, references);
  
    }
  
  
  
    // Clone attributes if they exist
  
    var attrs = extract_attr( jsonml );
  
    if ( attrs ) {
  
      jsonml[ 1 ] = {};
  
      for ( i in attrs ) {
  
        jsonml[ 1 ][ i ] = attrs[ i ];
  
      }
  
      attrs = jsonml[ 1 ];
  
    }
  
  
  
    // basic case
  
    if ( typeof jsonml === "string" ) {
  
      return jsonml;
  
    }
  
  
  
    // convert this node
  
    switch ( jsonml[ 0 ] ) {
  
      case "header":
  
        jsonml[ 0 ] = "h" + jsonml[ 1 ].level;
  
        delete jsonml[ 1 ].level;
  
        break;
  
      case "bulletlist":
  
        jsonml[ 0 ] = "ul";
  
        break;
  
      case "numberlist":
  
        jsonml[ 0 ] = "ol";
  
        break;
  
      case "listitem":
  
        jsonml[ 0 ] = "li";
  
        break;
  
      case "para":
  
        jsonml[ 0 ] = "p";
  
        break;
  
      case "markdown":
  
        jsonml[ 0 ] = "html";
  
        if ( attrs ) delete attrs.references;
  
        break;
  
      case "code_block":
  
        jsonml[ 0 ] = "pre";
  
        i = attrs ? 2 : 1;
  
        var code = [ "code" ];
  
        code.push.apply( code, jsonml.splice( i ) );
  
        jsonml[ i ] = code;
  
        break;
  
      case "inlinecode":
  
        jsonml[ 0 ] = "code";
  
        break;
  
      case "img":
  
        jsonml[ 1 ].src = jsonml[ 1 ].href;
  
        delete jsonml[ 1 ].href;
  
        break;
  
      case "linebreak":
  
        jsonml[ 0 ] = "br";
  
      break;
  
      case "link":
  
        jsonml[ 0 ] = "a";
  
        break;
  
      case "link_ref":
  
        jsonml[ 0 ] = "a";
  
  
  
        // grab this ref and clean up the attribute node
  
        var ref = references[ attrs.ref ];
  
  
  
        // if the reference exists, make the link
  
        if ( ref ) {
  
          delete attrs.ref;
  
  
  
          // add in the href and title, if present
  
          attrs.href = ref.href;
  
          if ( ref.title ) {
  
            attrs.title = ref.title;
  
          }
  
  
  
          // get rid of the unneeded original text
  
          delete attrs.original;
  
        }
  
        // the reference doesn't exist, so revert to plain text
  
        else {
  
          return attrs.original;
  
        }
  
        break;
  
      case "img_ref":
  
        jsonml[ 0 ] = "img";
  
  
  
        // grab this ref and clean up the attribute node
  
        var ref = references[ attrs.ref ];
  
  
  
        // if the reference exists, make the link
  
        if ( ref ) {
  
          delete attrs.ref;
  
  
  
          // add in the href and title, if present
  
          attrs.src = ref.href;
  
          if ( ref.title ) {
  
            attrs.title = ref.title;
  
          }
  
  
  
          // get rid of the unneeded original text
  
          delete attrs.original;
  
        }
  
        // the reference doesn't exist, so revert to plain text
  
        else {
  
          return attrs.original;
  
        }
  
        break;
  
    }
  
  
  
    // convert all the children
  
    i = 1;
  
  
  
    // deal with the attribute node, if it exists
  
    if ( attrs ) {
  
      // if there are keys, skip over it
  
      for ( var key in jsonml[ 1 ] ) {
  
        i = 2;
  
      }
  
      // if there aren't, remove it
  
      if ( i === 1 ) {
  
        jsonml.splice( i, 1 );
  
      }
  
    }
  
  
  
    for ( ; i < jsonml.length; ++i ) {
  
      jsonml[ i ] = arguments.callee( jsonml[ i ], references, options );
  
    }
  
  
  
    return jsonml;
  
  }
  
  
  
  
  
  // merges adjacent text nodes into a single node
  
  function merge_text_nodes( jsonml ) {
  
    // skip the tag name and attribute hash
  
    var i = extract_attr( jsonml ) ? 2 : 1;
  
  
  
    while ( i < jsonml.length ) {
  
      // if it's a string check the next item too
  
      if ( typeof jsonml[ i ] === "string" ) {
  
        if ( i + 1 < jsonml.length && typeof jsonml[ i + 1 ] === "string" ) {
  
          // merge the second string into the first and remove it
  
          jsonml[ i ] += jsonml.splice( i + 1, 1 )[ 0 ];
  
        }
  
        else {
  
          ++i;
  
        }
  
      }
  
      // if it's not a string recurse
  
      else {
  
        arguments.callee( jsonml[ i ] );
  
        ++i;
  
      }
  
    }
  
  }
  
  
  
  } )( (function() {
  
    if ( typeof exports === "undefined" ) {
  
      window.markdown = {};
  
      return window.markdown;
  
    }
  
    else {
  
      return exports;
  
    }
  
  } )() );