text: //
  // showdown.js -- A javascript port of Markdown.
  //
  // Copyright (c) 2007 John Fraser.
  //
  // Original Markdown Copyright (c) 2004-2005 John Gruber
  //   <http://daringfireball.net/projects/markdown/>
  //
  // Redistributable under a BSD-style open source license.
  // See license.txt for more information.
  //
  // The full source distribution is at:
  //
  //                A A L
  //                T C A
  //                T K B
  //
  //   <http://www.attacklab.net/>
  //
  
  //
  // Wherever possible, Showdown is a straight, line-by-line port
  // of the Perl version of Markdown.
  //
  // This is not a normal parser design; it's basically just a
  // series of string substitutions.  It's hard to read and
  // maintain this way,  but keeping Showdown close to the original
  // design makes it easier to port new features.
  //
  // More importantly, Showdown behaves like markdown.pl in most
  // edge cases.  So web applications can do client-side preview
  // in Javascript, and then build identical HTML on the server.
  //
  // This port needs the new RegExp functionality of ECMA 262,
  // 3rd Edition (i.e. Javascript 1.5).  Most modern web browsers
  // should do fine.  Even with the new regular expression features,
  // We do a lot of work to emulate Perl's regex functionality.
  // The tricky changes in this file mostly have the "attacklab:"
  // label.  Major or self-explanatory changes don't.
  //
  // Smart diff tools like Araxis Merge will be able to match up
  // this file with markdown.pl in a useful way.  A little tweaking
  // helps: in a copy of markdown.pl, replace "#" with "//" and
  // replace "$text" with "text".  Be sure to ignore whitespace
  // and line endings.
  //
  
  
  //
  // Showdown usage:
  //
  //   var text = "Markdown *rocks*.";
  //
  //   var converter = new Showdown.converter();
  //   var html = converter.makeHtml(text);
  //
  //   alert(html);
  //
  // Note: move the sample code to the bottom of this
  // file before uncommenting it.
  //
  
  
  //
  // Showdown namespace
  //
  var Showdown = { extensions: {} };
  
  //
  // forEach
  //
  var forEach = Showdown.forEach = function(obj, callback) {
      if (typeof obj.forEach === 'function') {
          obj.forEach(callback);
      } else {
          var i, len = obj.length;
          for (i = 0; i < len; i++) {
              callback(obj[i], i, obj);
          }
      }
  };
  
  //
  // Standard extension naming
  //
  var stdExtName = function(s) {
      return s.replace(/[_-]||\s/g, '').toLowerCase();
  };
  
  //
  // converter
  //
  // Wraps all "globals" so that the only thing
  // exposed is makeHtml().
  //
  Showdown.converter = function(converter_options) {
  
  //
  // Globals:
  //
  
  // Global hashes, used by various utility routines
  var g_urls;
  var g_titles;
  var g_html_blocks;
  
  // Used to track when we're inside an ordered or unordered list
  // (see _ProcessListItems() for details):
  var g_list_level = 0;
  
  // Global extensions
  var g_lang_extensions = [];
  var g_output_modifiers = [];
  
  
  //
  // Automatic Extension Loading (node only):
  //
  
  if (typeof module !== 'undefind' && typeof exports !== 'undefined' && typeof require !== 'undefind') {
      var fs = require('fs');
  
      if (fs) {
          // Search extensions folder
          var extensions = fs.readdirSync((__dirname || '.')+'/extensions').filter(function(file){
              return ~file.indexOf('.js');
          }).map(function(file){
              return file.replace(/\.js$/, '');
          });
          // Load extensions into Showdown namespace
          Showdown.forEach(extensions, function(ext){
              var name = stdExtName(ext);
              Showdown.extensions[name] = require('./extensions/' + ext);
          });
      }
  }
  
  this.makeHtml = function(text) {
  //
  // Main function. The order in which other subs are called here is
  // essential. Link and image substitutions need to happen before
  // _EscapeSpecialCharsWithinTagAttributes(), so that any *'s or _'s in the <a>
  // and <img> tags get encoded.
  //
  
      // Clear the global hashes. If we don't clear these, you get conflicts
      // from other articles when generating a page which contains more than
      // one article (e.g. an index page that shows the N most recent
      // articles):
      g_urls = {};
      g_titles = {};
      g_html_blocks = [];
  
      // attacklab: Replace ~ with ~T
      // This lets us use tilde as an escape char to avoid md5 hashes
      // The choice of character is arbitray; anything that isn't
      // magic in Markdown will work.
      text = text.replace(/~/g,"~T");
  
      // attacklab: Replace $ with ~D
      // RegExp interprets $ as a special character
      // when it's in a replacement string
      text = text.replace(/\$/g,"~D");
  
      // Standardize line endings
      text = text.replace(/\r\n/g,"\n"); // DOS to Unix
      text = text.replace(/\r/g,"\n"); // Mac to Unix
  
      // Make sure text begins and ends with a couple of newlines:
      text = "\n\n" + text + "\n\n";
  
      // Convert all tabs to spaces.
      text = _Detab(text);
  
      // Strip any lines consisting only of spaces and tabs.
      // This makes subsequent regexen easier to write, because we can
      // match consecutive blank lines with /\n+/ instead of something
      // contorted like /[ \t]*\n+/ .
      text = text.replace(/^[ \t]+$/mg,"");
  
      // Run language extensions
      Showdown.forEach(g_lang_extensions, function(x){
          text = _ExecuteExtension(x, text);
      });
  
      // Handle github codeblocks prior to running HashHTML so that
      // HTML contained within the codeblock gets escaped propertly
      text = _DoGithubCodeBlocks(text);
  
      // Turn block-level HTML blocks into hash entries
      text = _HashHTMLBlocks(text);
  
      // Strip link definitions, store in hashes.
      text = _StripLinkDefinitions(text);
  
      text = _RunBlockGamut(text);
  
      text = _UnescapeSpecialChars(text);
  
      // attacklab: Restore dollar signs
      text = text.replace(/~D/g,"$$");
  
      // attacklab: Restore tildes
      text = text.replace(/~T/g,"~");
  
      // Run output modifiers
      Showdown.forEach(g_output_modifiers, function(x){
          text = _ExecuteExtension(x, text);
      });
  
      return text;
  };
  //
  // Options:
  //
  
  // Parse extensions options into separate arrays
  if (converter_options && converter_options.extensions) {
  
    var self = this;
  
      // Iterate over each plugin
      Showdown.forEach(converter_options.extensions, function(plugin){
  
          // Assume it's a bundled plugin if a string is given
          if (typeof plugin === 'string') {
              plugin = Showdown.extensions[stdExtName(plugin)];
          }
  
          if (typeof plugin === 'function') {
              // Iterate over each extension within that plugin
              Showdown.forEach(plugin(self), function(ext){
                  // Sort extensions by type
                  if (ext.type) {
                      if (ext.type === 'language' || ext.type === 'lang') {
                          g_lang_extensions.push(ext);
                      } else if (ext.type === 'output' || ext.type === 'html') {
                          g_output_modifiers.push(ext);
                      }
                  } else {
                      // Assume language extension
                      g_output_modifiers.push(ext);
                  }
              });
          } else {
              throw "Extension '" + plugin + "' could not be loaded.  It was either not found or is not a valid extension.";
          }
      });
  }
  
  
  var _ExecuteExtension = function(ext, text) {
      if (ext.regex) {
          var re = new RegExp(ext.regex, 'g');
          return text.replace(re, ext.replace);
      } else if (ext.filter) {
          return ext.filter(text);
      }
  };
  
  var _StripLinkDefinitions = function(text) {
  //
  // Strips link definitions from text, stores the URLs and titles in
  // hash references.
  //
  
      // Link defs are in the form: ^[id]: url "optional title"
  
      /*
          var text = text.replace(/
                  ^[ ]{0,3}\[(.+)\]:  // id = $1  attacklab: g_tab_width - 1
                    [ \t]*
                    \n?                // maybe *one* newline
                    [ \t]*
                  <?(\S+?)>?            // url = $2
                    [ \t]*
                    \n?                // maybe one newline
                    [ \t]*
                  (?:
                    (\n*)                // any lines skipped = $3 attacklab: lookbehind removed
                    ["(]
                    (.+?)                // title = $4
                    [")]
                    [ \t]*
                  )?                    // title is optional
                  (?:\n+|$)
                /gm,
                function(){...});
      */
  
      // attacklab: sentinel workarounds for lack of \A and \Z, safari\khtml bug
      text += "~0";
  
      text = text.replace(/^[ ]{0,3}\[(.+)\]:[ \t]*\n?[ \t]*<?(\S+?)>?[ \t]*\n?[ \t]*(?:(\n*)["(](.+?)[")][ \t]*)?(?:\n+|(?=~0))/gm,
          function (wholeMatch,m1,m2,m3,m4) {
              m1 = m1.toLowerCase();
              g_urls[m1] = _EncodeAmpsAndAngles(m2);  // Link IDs are case-insensitive
              if (m3) {
                  // Oops, found blank lines, so it's not a title.
                  // Put back the parenthetical statement we stole.
                  return m3+m4;
              } else if (m4) {
                  g_titles[m1] = m4.replace(/"/g,"&quot;");
              }
  
              // Completely remove the definition from the text
              return "";
          }
      );
  
      // attacklab: strip sentinel
      text = text.replace(/~0/,"");
  
      return text;
  }
  
  
  var _HashHTMLBlocks = function(text) {
      // attacklab: Double up blank lines to reduce lookaround
      text = text.replace(/\n/g,"\n\n");
  
      // Hashify HTML blocks:
      // We only want to do this for block-level HTML tags, such as headers,
      // lists, and tables. That's because we still want to wrap <p>s around
      // "paragraphs" that are wrapped in non-block-level tags, such as anchors,
      // phrase emphasis, and spans. The list of tags we're looking for is
      // hard-coded:
      var block_tags_a = "p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|script|noscript|form|fieldset|iframe|math|ins|del|style|section|header|footer|nav|article|aside";
      var block_tags_b = "p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|script|noscript|form|fieldset|iframe|math|style|section|header|footer|nav|article|aside";
  
      // First, look for nested blocks, e.g.:
      //   <div>
      //     <div>
      //     tags for inner block must be indented.
      //     </div>
      //   </div>
      //
      // The outermost tags must start at the left margin for this to match, and
      // the inner nested divs must be indented.
      // We need to do this before the next, more liberal match, because the next
      // match will start at the first `<div>` and stop at the first `</div>`.
  
      // attacklab: This regex can be expensive when it fails.
      /*
          var text = text.replace(/
          (                        // save in $1
              ^                    // start of line  (with /m)
              <($block_tags_a)    // start tag = $2
              \b                    // word break
                                  // attacklab: hack around khtml/pcre bug...
              [^\r]*?\n            // any number of lines, minimally matching
              </\2>                // the matching end tag
              [ \t]*                // trailing spaces/tabs
              (?=\n+)                // followed by a newline
          )                        // attacklab: there are sentinel newlines at end of document
          /gm,function(){...}};
      */
      text = text.replace(/^(<(p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|script|noscript|form|fieldset|iframe|math|ins|del)\b[^\r]*?\n<\/\2>[ \t]*(?=\n+))/gm,hashElement);
  
      //
      // Now match more liberally, simply from `\n<tag>` to `</tag>\n`
      //
  
      /*
          var text = text.replace(/
          (                        // save in $1
              ^                    // start of line  (with /m)
              <($block_tags_b)    // start tag = $2
              \b                    // word break
                                  // attacklab: hack around khtml/pcre bug...
              [^\r]*?                // any number of lines, minimally matching
              </\2>                // the matching end tag
              [ \t]*                // trailing spaces/tabs
              (?=\n+)                // followed by a newline
          )                        // attacklab: there are sentinel newlines at end of document
          /gm,function(){...}};
      */
      text = text.replace(/^(<(p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|script|noscript|form|fieldset|iframe|math|style|section|header|footer|nav|article|aside)\b[^\r]*?<\/\2>[ \t]*(?=\n+)\n)/gm,hashElement);
  
      // Special case just for <hr />. It was easier to make a special case than
      // to make the other regex more complicated.
  
      /*
          text = text.replace(/
          (                        // save in $1
              \n\n                // Starting after a blank line
              [ ]{0,3}
              (<(hr)                // start tag = $2
              \b                    // word break
              ([^<>])*?            //
              \/?>)                // the matching end tag
              [ \t]*
              (?=\n{2,})            // followed by a blank line
          )
          /g,hashElement);
      */
      text = text.replace(/(\n[ ]{0,3}(<(hr)\b([^<>])*?\/?>)[ \t]*(?=\n{2,}))/g,hashElement);
  
      // Special case for standalone HTML comments:
  
      /*
          text = text.replace(/
          (                        // save in $1
              \n\n                // Starting after a blank line
              [ ]{0,3}            // attacklab: g_tab_width - 1
              <!
              (--[^\r]*?--\s*)+
              >
              [ \t]*
              (?=\n{2,})            // followed by a blank line
          )
          /g,hashElement);
      */
      text = text.replace(/(\n\n[ ]{0,3}<!(--[^\r]*?--\s*)+>[ \t]*(?=\n{2,}))/g,hashElement);
  
      // PHP and ASP-style processor instructions (<?...?> and <%...%>)
  
      /*
          text = text.replace(/
          (?:
              \n\n                // Starting after a blank line
          )
          (                        // save in $1
              [ ]{0,3}            // attacklab: g_tab_width - 1
              (?:
                  <([?%])            // $2
                  [^\r]*?
                  \2>
              )
              [ \t]*
              (?=\n{2,})            // followed by a blank line
          )
          /g,hashElement);
      */
      text = text.replace(/(?:\n\n)([ ]{0,3}(?:<([?%])[^\r]*?\2>)[ \t]*(?=\n{2,}))/g,hashElement);
  
      // attacklab: Undo double lines (see comment at top of this function)
      text = text.replace(/\n\n/g,"\n");
      return text;
  }
  
  var hashElement = function(wholeMatch,m1) {
      var blockText = m1;
  
      // Undo double lines
      blockText = blockText.replace(/\n\n/g,"\n");
      blockText = blockText.replace(/^\n/,"");
  
      // strip trailing blank lines
      blockText = blockText.replace(/\n+$/g,"");
  
      // Replace the element text with a marker ("~KxK" where x is its key)
      blockText = "\n\n~K" + (g_html_blocks.push(blockText)-1) + "K\n\n";
  
      return blockText;
  };
  
  var _RunBlockGamut = function(text) {
  //
  // These are all the transformations that form block-level
  // tags like paragraphs, headers, and list items.
  //
      text = _DoHeaders(text);
  
      // Do Horizontal Rules:
      var key = hashBlock("<hr />");
      text = text.replace(/^[ ]{0,2}([ ]?\*[ ]?){3,}[ \t]*$/gm,key);
      text = text.replace(/^[ ]{0,2}([ ]?\-[ ]?){3,}[ \t]*$/gm,key);
      text = text.replace(/^[ ]{0,2}([ ]?\_[ ]?){3,}[ \t]*$/gm,key);
  
      text = _DoLists(text);
      text = _DoCodeBlocks(text);
      text = _DoBlockQuotes(text);
  
      // We already ran _HashHTMLBlocks() before, in Markdown(), but that
      // was to escape raw HTML in the original Markdown source. This time,
      // we're escaping the markup we've just created, so that we don't wrap
      // <p> tags around block-level tags.
      text = _HashHTMLBlocks(text);
      text = _FormParagraphs(text);
  
      return text;
  };
  
  
  var _RunSpanGamut = function(text) {
  //
  // These are all the transformations that occur *within* block-level
  // tags like paragraphs, headers, and list items.
  //
  
      text = _DoCodeSpans(text);
      text = _EscapeSpecialCharsWithinTagAttributes(text);
      text = _EncodeBackslashEscapes(text);
  
      // Process anchor and image tags. Images must come first,
      // because ![foo][f] looks like an anchor.
      text = _DoImages(text);
      text = _DoAnchors(text);
  
      // Make links out of things like `<http://example.com/>`
      // Must come after _DoAnchors(), because you can use < and >
      // delimiters in inline links like [this](<url>).
      text = _DoAutoLinks(text);
      text = _EncodeAmpsAndAngles(text);
      text = _DoItalicsAndBold(text);
  
      // Do hard breaks:
      text = text.replace(/  +\n/g," <br />\n");
  
      return text;
  }
  
  var _EscapeSpecialCharsWithinTagAttributes = function(text) {
  //
  // Within tags -- meaning between < and > -- encode [\ ` * _] so they
  // don't conflict with their use in Markdown for code, italics and strong.
  //
  
      // Build a regex to find HTML tags and comments.  See Friedl's
      // "Mastering Regular Expressions", 2nd Ed., pp. 200-201.
      var regex = /(<[a-z\/!$]("[^"]*"|'[^']*'|[^'">])*>|<!(--.*?--\s*)+>)/gi;
  
      text = text.replace(regex, function(wholeMatch) {
          var tag = wholeMatch.replace(/(.)<\/?code>(?=.)/g,"$1`");
          tag = escapeCharacters(tag,"\\`*_");
          return tag;
      });
  
      return text;
  }
  
  var _DoAnchors = function(text) {
  //
  // Turn Markdown link shortcuts into XHTML <a> tags.
  //
      //
      // First, handle reference-style links: [link text] [id]
      //
  
      /*
          text = text.replace(/
          (                            // wrap whole match in $1
              \[
              (
                  (?:
                      \[[^\]]*\]        // allow brackets nested one level
                      |
                      [^\[]            // or anything else
                  )*
              )
              \]
  
              [ ]?                    // one optional space
              (?:\n[ ]*)?                // one optional newline followed by spaces
  
              \[
              (.*?)                    // id = $3
              \]
          )()()()()                    // pad remaining backreferences
          /g,_DoAnchors_callback);
      */
      text = text.replace(/(\[((?:\[[^\]]*\]|[^\[\]])*)\][ ]?(?:\n[ ]*)?\[(.*?)\])()()()()/g,writeAnchorTag);
  
      //
      // Next, inline-style links: [link text](url "optional title")
      //
  
      /*
          text = text.replace(/
              (                        // wrap whole match in $1
                  \[
                  (
                      (?:
                          \[[^\]]*\]    // allow brackets nested one level
                      |
                      [^\[\]]            // or anything else
                  )
              )
              \]
              \(                        // literal paren
              [ \t]*
              ()                        // no id, so leave $3 empty
              <?(.*?)>?                // href = $4
              [ \t]*
              (                        // $5
                  (['"])                // quote char = $6
                  (.*?)                // Title = $7
                  \6                    // matching quote
                  [ \t]*                // ignore any spaces/tabs between closing quote and )
              )?                        // title is optional
              \)
          )
          /g,writeAnchorTag);
      */
      text = text.replace(/(\[((?:\[[^\]]*\]|[^\[\]])*)\]\([ \t]*()<?(.*?(?:\(.*?\).*?)?)>?[ \t]*((['"])(.*?)\6[ \t]*)?\))/g,writeAnchorTag);
  
      //
      // Last, handle reference-style shortcuts: [link text]
      // These must come last in case you've also got [link test][1]
      // or [link test](/foo)
      //
  
      /*
          text = text.replace(/
          (                             // wrap whole match in $1
              \[
              ([^\[\]]+)                // link text = $2; can't contain '[' or ']'
              \]
          )()()()()()                    // pad rest of backreferences
          /g, writeAnchorTag);
      */
      text = text.replace(/(\[([^\[\]]+)\])()()()()()/g, writeAnchorTag);
  
      return text;
  }
  
  var writeAnchorTag = function(wholeMatch,m1,m2,m3,m4,m5,m6,m7) {
      if (m7 == undefined) m7 = "";
      var whole_match = m1;
      var link_text   = m2;
      var link_id     = m3.toLowerCase();
      var url        = m4;
      var title    = m7;
  
      if (url == "") {
          if (link_id == "") {
              // lower-case and turn embedded newlines into spaces
              link_id = link_text.toLowerCase().replace(/ ?\n/g," ");
          }
          url = "#"+link_id;
  
          if (g_urls[link_id] != undefined) {
              url = g_urls[link_id];
              if (g_titles[link_id] != undefined) {
                  title = g_titles[link_id];
              }
          }
          else {
              if (whole_match.search(/\(\s*\)$/m)>-1) {
                  // Special case for explicit empty url
                  url = "";
              } else {
                  return whole_match;
              }
          }
      }
  
      url = escapeCharacters(url,"*_");
      var result = "<a href=\"" + url + "\"";
  
      if (title != "") {
          title = title.replace(/"/g,"&quot;");
          title = escapeCharacters(title,"*_");
          result +=  " title=\"" + title + "\"";
      }
  
      result += ">" + link_text + "</a>";
  
      return result;
  }
  
  
  var _DoImages = function(text) {
  //
  // Turn Markdown image shortcuts into <img> tags.
  //
  
      //
      // First, handle reference-style labeled images: ![alt text][id]
      //
  
      /*
          text = text.replace(/
          (                        // wrap whole match in $1
              !\[
              (.*?)                // alt text = $2
              \]
  
              [ ]?                // one optional space
              (?:\n[ ]*)?            // one optional newline followed by spaces
  
              \[
              (.*?)                // id = $3
              \]
          )()()()()                // pad rest of backreferences
          /g,writeImageTag);
      */
      text = text.replace(/(!\[(.*?)\][ ]?(?:\n[ ]*)?\[(.*?)\])()()()()/g,writeImageTag);
  
      //
      // Next, handle inline images:  ![alt text](url "optional title")
      // Don't forget: encode * and _
  
      /*
          text = text.replace(/
          (                        // wrap whole match in $1
              !\[
              (.*?)                // alt text = $2
              \]
              \s?                    // One optional whitespace character
              \(                    // literal paren
              [ \t]*
              ()                    // no id, so leave $3 empty
              <?(\S+?)>?            // src url = $4
              [ \t]*
              (                    // $5
                  (['"])            // quote char = $6
                  (.*?)            // title = $7
                  \6                // matching quote
                  [ \t]*
              )?                    // title is optional
          \)
          )
          /g,writeImageTag);
      */
      text = text.replace(/(!\[(.*?)\]\s?\([ \t]*()<?(\S+?)>?[ \t]*((['"])(.*?)\6[ \t]*)?\))/g,writeImageTag);
  
      return text;
  }
  
  var writeImageTag = function(wholeMatch,m1,m2,m3,m4,m5,m6,m7) {
      var whole_match = m1;
      var alt_text   = m2;
      var link_id     = m3.toLowerCase();
      var url        = m4;
      var title    = m7;
  
      if (!title) title = "";
  
      if (url == "") {
          if (link_id == "") {
              // lower-case and turn embedded newlines into spaces
              link_id = alt_text.toLowerCase().replace(/ ?\n/g," ");
          }
          url = "#"+link_id;
  
          if (g_urls[link_id] != undefined) {
              url = g_urls[link_id];
              if (g_titles[link_id] != undefined) {
                  title = g_titles[link_id];
              }
          }
          else {
              return whole_match;
          }
      }
  
      alt_text = alt_text.replace(/"/g,"&quot;");
      url = escapeCharacters(url,"*_");
      var result = "<img src=\"" + url + "\" alt=\"" + alt_text + "\"";
  
      // attacklab: Markdown.pl adds empty title attributes to images.
      // Replicate this bug.
  
      //if (title != "") {
          title = title.replace(/"/g,"&quot;");
          title = escapeCharacters(title,"*_");
          result +=  " title=\"" + title + "\"";
      //}
  
      result += " />";
  
      return result;
  }
  
  
  var _DoHeaders = function(text) {
  
      // Setext-style headers:
      //    Header 1
      //    ========
      //
      //    Header 2
      //    --------
      //
      text = text.replace(/^(.+)[ \t]*\n=+[ \t]*\n+/gm,
          function(wholeMatch,m1){return hashBlock('<h1 id="' + headerId(m1) + '">' + _RunSpanGamut(m1) + "</h1>");});
  
      text = text.replace(/^(.+)[ \t]*\n-+[ \t]*\n+/gm,
          function(matchFound,m1){return hashBlock('<h2 id="' + headerId(m1) + '">' + _RunSpanGamut(m1) + "</h2>");});
  
      // atx-style headers:
      //  # Header 1
      //  ## Header 2
      //  ## Header 2 with closing hashes ##
      //  ...
      //  ###### Header 6
      //
  
      /*
          text = text.replace(/
              ^(\#{1,6})                // $1 = string of #'s
              [ \t]*
              (.+?)                    // $2 = Header text
              [ \t]*
              \#*                        // optional closing #'s (not counted)
              \n+
          /gm, function() {...});
      */
  
      text = text.replace(/^(\#{1,6})[ \t]*(.+?)[ \t]*\#*\n+/gm,
          function(wholeMatch,m1,m2) {
              var h_level = m1.length;
              return hashBlock("<h" + h_level + ' id="' + headerId(m2) + '">' + _RunSpanGamut(m2) + "</h" + h_level + ">");
          });
  
      function headerId(m) {
          return m.replace(/[^\w]/g, '').toLowerCase();
      }
      return text;
  }
  
  // This declaration keeps Dojo compressor from outputting garbage:
  var _ProcessListItems;
  
  var _DoLists = function(text) {
  //
  // Form HTML ordered (numbered) and unordered (bulleted) lists.
  //
  
      // attacklab: add sentinel to hack around khtml/safari bug:
      // http://bugs.webkit.org/show_bug.cgi?id=11231
      text += "~0";
  
      // Re-usable pattern to match any entirel ul or ol list:
  
      /*
          var whole_list = /
          (                                    // $1 = whole list
              (                                // $2
                  [ ]{0,3}                    // attacklab: g_tab_width - 1
                  ([*+-]|\d+[.])                // $3 = first list item marker
                  [ \t]+
              )
              [^\r]+?
              (                                // $4
                  ~0                            // sentinel for workaround; should be $
              |
                  \n{2,}
                  (?=\S)
                  (?!                            // Negative lookahead for another list item marker
                      [ \t]*
                      (?:[*+-]|\d+[.])[ \t]+
                  )
              )
          )/g
      */
      var whole_list = /^(([ ]{0,3}([*+-]|\d+[.])[ \t]+)[^\r]+?(~0|\n{2,}(?=\S)(?![ \t]*(?:[*+-]|\d+[.])[ \t]+)))/gm;
  
      if (g_list_level) {
          text = text.replace(whole_list,function(wholeMatch,m1,m2) {
              var list = m1;
              var list_type = (m2.search(/[*+-]/g)>-1) ? "ul" : "ol";
  
              // Turn double returns into triple returns, so that we can make a
              // paragraph for the last item in a list, if necessary:
              list = list.replace(/\n{2,}/g,"\n\n\n");;
              var result = _ProcessListItems(list);
  
              // Trim any trailing whitespace, to put the closing `</$list_type>`
              // up on the preceding line, to get it past the current stupid
              // HTML block parser. This is a hack to work around the terrible
              // hack that is the HTML block parser.
              result = result.replace(/\s+$/,"");
              result = "<"+list_type+">" + result + "</"+list_type+">\n";
              return result;
          });
      } else {
          whole_list = /(\n\n|^\n?)(([ ]{0,3}([*+-]|\d+[.])[ \t]+)[^\r]+?(~0|\n{2,}(?=\S)(?![ \t]*(?:[*+-]|\d+[.])[ \t]+)))/g;
          text = text.replace(whole_list,function(wholeMatch,m1,m2,m3) {
              var runup = m1;
              var list = m2;
  
              var list_type = (m3.search(/[*+-]/g)>-1) ? "ul" : "ol";
              // Turn double returns into triple returns, so that we can make a
              // paragraph for the last item in a list, if necessary:
              var list = list.replace(/\n{2,}/g,"\n\n\n");;
              var result = _ProcessListItems(list);
              result = runup + "<"+list_type+">\n" + result + "</"+list_type+">\n";
              return result;
          });
      }
  
      // attacklab: strip sentinel
      text = text.replace(/~0/,"");
  
      return text;
  }
  
  _ProcessListItems = function(list_str) {
  //
  //  Process the contents of a single ordered or unordered list, splitting it
  //  into individual list items.
  //
      // The $g_list_level global keeps track of when we're inside a list.
      // Each time we enter a list, we increment it; when we leave a list,
      // we decrement. If it's zero, we're not in a list anymore.
      //
      // We do this because when we're not inside a list, we want to treat
      // something like this:
      //
      //    I recommend upgrading to version
      //    8. Oops, now this line is treated
      //    as a sub-list.
      //
      // As a single paragraph, despite the fact that the second line starts
      // with a digit-period-space sequence.
      //
      // Whereas when we're inside a list (or sub-list), that line will be
      // treated as the start of a sub-list. What a kludge, huh? This is
      // an aspect of Markdown's syntax that's hard to parse perfectly
      // without resorting to mind-reading. Perhaps the solution is to
      // change the syntax rules such that sub-lists must start with a
      // starting cardinal number; e.g. "1." or "a.".
  
      g_list_level++;
  
      // trim trailing blank lines:
      list_str = list_str.replace(/\n{2,}$/,"\n");
  
      // attacklab: add sentinel to emulate \z
      list_str += "~0";
  
      /*
          list_str = list_str.replace(/
              (\n)?                            // leading line = $1
              (^[ \t]*)                        // leading whitespace = $2
              ([*+-]|\d+[.]) [ \t]+            // list marker = $3
              ([^\r]+?                        // list item text   = $4
              (\n{1,2}))
              (?= \n* (~0 | \2 ([*+-]|\d+[.]) [ \t]+))
          /gm, function(){...});
      */
      list_str = list_str.replace(/(\n)?(^[ \t]*)([*+-]|\d+[.])[ \t]+([^\r]+?(\n{1,2}))(?=\n*(~0|\2([*+-]|\d+[.])[ \t]+))/gm,
          function(wholeMatch,m1,m2,m3,m4){
              var item = m4;
              var leading_line = m1;
              var leading_space = m2;
  
              if (leading_line || (item.search(/\n{2,}/)>-1)) {
                  item = _RunBlockGamut(_Outdent(item));
              }
              else {
                  // Recursion for sub-lists:
                  item = _DoLists(_Outdent(item));
                  item = item.replace(/\n$/,""); // chomp(item)
                  item = _RunSpanGamut(item);
              }
  
              return  "<li>" + item + "</li>\n";
          }
      );
  
      // attacklab: strip sentinel
      list_str = list_str.replace(/~0/g,"");
  
      g_list_level--;
      return list_str;
  }
  
  
  var _DoCodeBlocks = function(text) {
  //
  //  Process Markdown `<pre><code>` blocks.
  //
  
      /*
          text = text.replace(text,
              /(?:\n\n|^)
              (                                // $1 = the code block -- one or more lines, starting with a space/tab
                  (?:
                      (?:[ ]{4}|\t)            // Lines must start with a tab or a tab-width of spaces - attacklab: g_tab_width
                      .*\n+
                  )+
              )
              (\n*[ ]{0,3}[^ \t\n]|(?=~0))    // attacklab: g_tab_width
          /g,function(){...});
      */
  
      // attacklab: sentinel workarounds for lack of \A and \Z, safari\khtml bug
      text += "~0";
  
      text = text.replace(/(?:\n\n|^)((?:(?:[ ]{4}|\t).*\n+)+)(\n*[ ]{0,3}[^ \t\n]|(?=~0))/g,
          function(wholeMatch,m1,m2) {
              var codeblock = m1;
              var nextChar = m2;
  
              codeblock = _EncodeCode( _Outdent(codeblock));
              codeblock = _Detab(codeblock);
              codeblock = codeblock.replace(/^\n+/g,""); // trim leading newlines
              codeblock = codeblock.replace(/\n+$/g,""); // trim trailing whitespace
  
              codeblock = "<pre><code>" + codeblock + "\n</code></pre>";
  
              return hashBlock(codeblock) + nextChar;
          }
      );
  
      // attacklab: strip sentinel
      text = text.replace(/~0/,"");
  
      return text;
  };
  
  var _DoGithubCodeBlocks = function(text) {
  //
  //  Process Github-style code blocks
  //  Example:
  //  ```ruby
  //  def hello_world(x)
  //    puts "Hello, #{x}"
  //  end
  //  ```
  //
  
  
      // attacklab: sentinel workarounds for lack of \A and \Z, safari\khtml bug
      text += "~0";
  
      text = text.replace(/(?:^|\n)```(.*)\n([\s\S]*?)\n```/g,
          function(wholeMatch,m1,m2) {
              var language = m1;
              var codeblock = m2;
  
              codeblock = _EncodeCode(codeblock);
              codeblock = _Detab(codeblock);
              codeblock = codeblock.replace(/^\n+/g,""); // trim leading newlines
              codeblock = codeblock.replace(/\n+$/g,""); // trim trailing whitespace
  
              codeblock = "<pre><code" + (language ? " class=\"" + language + '"' : "") + ">" + codeblock + "\n</code></pre>";
  
              return hashBlock(codeblock);
          }
      );
  
      // attacklab: strip sentinel
      text = text.replace(/~0/,"");
  
      return text;
  }
  
  var hashBlock = function(text) {
      text = text.replace(/(^\n+|\n+$)/g,"");
      return "\n\n~K" + (g_html_blocks.push(text)-1) + "K\n\n";
  }
  
  var _DoCodeSpans = function(text) {
  //
  //   *  Backtick quotes are used for <code></code> spans.
  //
  //   *  You can use multiple backticks as the delimiters if you want to
  //     include literal backticks in the code span. So, this input:
  //
  //         Just type ``foo `bar` baz`` at the prompt.
  //
  //       Will translate to:
  //
  //         <p>Just type <code>foo `bar` baz</code> at the prompt.</p>
  //
  //    There's no arbitrary limit to the number of backticks you
  //    can use as delimters. If you need three consecutive backticks
  //    in your code, use four for delimiters, etc.
  //
  //  *  You can use spaces to get literal backticks at the edges:
  //
  //         ... type `` `bar` `` ...
  //
  //       Turns to:
  //
  //         ... type <code>`bar`</code> ...
  //
  
      /*
          text = text.replace(/
              (^|[^\\])                    // Character before opening ` can't be a backslash
              (`+)                        // $2 = Opening run of `
              (                            // $3 = The code block
                  [^\r]*?
                  [^`]                    // attacklab: work around lack of lookbehind
              )
              \2                            // Matching closer
              (?!`)
          /gm, function(){...});
      */
  
      text = text.replace(/(^|[^\\])(`+)([^\r]*?[^`])\2(?!`)/gm,
          function(wholeMatch,m1,m2,m3,m4) {
              var c = m3;
              c = c.replace(/^([ \t]*)/g,"");    // leading whitespace
              c = c.replace(/[ \t]*$/g,"");    // trailing whitespace
              c = _EncodeCode(c);
              return m1+"<code>"+c+"</code>";
          });
  
      return text;
  }
  
  var _EncodeCode = function(text) {
  //
  // Encode/escape certain characters inside Markdown code runs.
  // The point is that in code, these characters are literals,
  // and lose their special Markdown meanings.
  //
      // Encode all ampersands; HTML entities are not
      // entities within a Markdown code span.
      text = text.replace(/&/g,"&amp;");
  
      // Do the angle bracket song and dance:
      text = text.replace(/</g,"&lt;");
      text = text.replace(/>/g,"&gt;");
  
      // Now, escape characters that are magic in Markdown:
      text = escapeCharacters(text,"\*_{}[]\\",false);
  
  // jj the line above breaks this:
  //---
  
  //* Item
  
  //   1. Subitem
  
  //            special char: *
  //---
  
      return text;
  }
  
  
  var _DoItalicsAndBold = function(text) {
  
      // <strong> must go first:
      text = text.replace(/(\*\*|__)(?=\S)([^\r]*?\S[*_]*)\1/g,
          "<strong>$2</strong>");
  
      text = text.replace(/(\*|_)(?=\S)([^\r]*?\S)\1/g,
          "<em>$2</em>");
  
      return text;
  }
  
  
  var _DoBlockQuotes = function(text) {
  
      /*
          text = text.replace(/
          (                                // Wrap whole match in $1
              (
                  ^[ \t]*>[ \t]?            // '>' at the start of a line
                  .+\n                    // rest of the first line
                  (.+\n)*                    // subsequent consecutive lines
                  \n*                        // blanks
              )+
          )
          /gm, function(){...});
      */
  
      text = text.replace(/((^[ \t]*>[ \t]?.+\n(.+\n)*\n*)+)/gm,
          function(wholeMatch,m1) {
              var bq = m1;
  
              // attacklab: hack around Konqueror 3.5.4 bug:
              // "----------bug".replace(/^-/g,"") == "bug"
  
              bq = bq.replace(/^[ \t]*>[ \t]?/gm,"~0");    // trim one level of quoting
  
              // attacklab: clean up hack
              bq = bq.replace(/~0/g,"");
  
              bq = bq.replace(/^[ \t]+$/gm,"");        // trim whitespace-only lines
              bq = _RunBlockGamut(bq);                // recurse
  
              bq = bq.replace(/(^|\n)/g,"$1  ");
              // These leading spaces screw with <pre> content, so we need to fix that:
              bq = bq.replace(
                      /(\s*<pre>[^\r]+?<\/pre>)/gm,
                  function(wholeMatch,m1) {
                      var pre = m1;
                      // attacklab: hack around Konqueror 3.5.4 bug:
                      pre = pre.replace(/^  /mg,"~0");
                      pre = pre.replace(/~0/g,"");
                      return pre;
                  });
  
              return hashBlock("<blockquote>\n" + bq + "\n</blockquote>");
          });
      return text;
  }
  
  
  var _FormParagraphs = function(text) {
  //
  //  Params:
  //    $text - string to process with html <p> tags
  //
  
      // Strip leading and trailing lines:
      text = text.replace(/^\n+/g,"");
      text = text.replace(/\n+$/g,"");
  
      var grafs = text.split(/\n{2,}/g);
      var grafsOut = [];
  
      //
      // Wrap <p> tags.
      //
      var end = grafs.length;
      for (var i=0; i<end; i++) {
          var str = grafs[i];
  
          // if this is an HTML marker, copy it
          if (str.search(/~K(\d+)K/g) >= 0) {
              grafsOut.push(str);
          }
          else if (str.search(/\S/) >= 0) {
              str = _RunSpanGamut(str);
              str = str.replace(/^([ \t]*)/g,"<p>");
              str += "</p>"
              grafsOut.push(str);
          }
  
      }
  
      //
      // Unhashify HTML blocks
      //
      end = grafsOut.length;
      for (var i=0; i<end; i++) {
          // if this is a marker for an html block...
          while (grafsOut[i].search(/~K(\d+)K/) >= 0) {
              var blockText = g_html_blocks[RegExp.$1];
              blockText = blockText.replace(/\$/g,"$$$$"); // Escape any dollar signs
              grafsOut[i] = grafsOut[i].replace(/~K\d+K/,blockText);
          }
      }
  
      return grafsOut.join("\n\n");
  }
  
  
  var _EncodeAmpsAndAngles = function(text) {
  // Smart processing for ampersands and angle brackets that need to be encoded.
  
      // Ampersand-encoding based entirely on Nat Irons's Amputator MT plugin:
      //   http://bumppo.net/projects/amputator/
      text = text.replace(/&(?!#?[xX]?(?:[0-9a-fA-F]+|\w+);)/g,"&amp;");
  
      // Encode naked <'s
      text = text.replace(/<(?![a-z\/?\$!])/gi,"&lt;");
  
      return text;
  }
  
  
  var _EncodeBackslashEscapes = function(text) {
  //
  //   Parameter:  String.
  //   Returns:    The string, with after processing the following backslash
  //               escape sequences.
  //
  
      // attacklab: The polite way to do this is with the new
      // escapeCharacters() function:
      //
      //     text = escapeCharacters(text,"\\",true);
      //     text = escapeCharacters(text,"`*_{}[]()>#+-.!",true);
      //
      // ...but we're sidestepping its use of the (slow) RegExp constructor
      // as an optimization for Firefox.  This function gets called a LOT.
  
      text = text.replace(/\\(\\)/g,escapeCharacters_callback);
      text = text.replace(/\\([`*_{}\[\]()>#+-.!])/g,escapeCharacters_callback);
      return text;
  }
  
  
  var _DoAutoLinks = function(text) {
  
      text = text.replace(/<((https?|ftp|dict):[^'">\s]+)>/gi,"<a href=\"$1\">$1</a>");
  
      // Email addresses: <address@domain.foo>
  
      /*
          text = text.replace(/
              <
              (?:mailto:)?
              (
                  [-.\w]+
                  \@
                  [-a-z0-9]+(\.[-a-z0-9]+)*\.[a-z]+
              )
              >
          /gi, _DoAutoLinks_callback());
      */
      text = text.replace(/<(?:mailto:)?([-.\w]+\@[-a-z0-9]+(\.[-a-z0-9]+)*\.[a-z]+)>/gi,
          function(wholeMatch,m1) {
              return _EncodeEmailAddress( _UnescapeSpecialChars(m1) );
          }
      );
  
      return text;
  }
  
  
  var _EncodeEmailAddress = function(addr) {
  //
  //  Input: an email address, e.g. "foo@example.com"
  //
  //  Output: the email address as a mailto link, with each character
  //    of the address encoded as either a decimal or hex entity, in
  //    the hopes of foiling most address harvesting spam bots. E.g.:
  //
  //    <a href="&#x6D;&#97;&#105;&#108;&#x74;&#111;:&#102;&#111;&#111;&#64;&#101;
  //       x&#x61;&#109;&#x70;&#108;&#x65;&#x2E;&#99;&#111;&#109;">&#102;&#111;&#111;
  //       &#64;&#101;x&#x61;&#109;&#x70;&#108;&#x65;&#x2E;&#99;&#111;&#109;</a>
  //
  //  Based on a filter by Matthew Wickline, posted to the BBEdit-Talk
  //  mailing list: <http://tinyurl.com/yu7ue>
  //
  
      var encode = [
          function(ch){return "&#"+ch.charCodeAt(0)+";";},
          function(ch){return "&#x"+ch.charCodeAt(0).toString(16)+";";},
          function(ch){return ch;}
      ];
  
      addr = "mailto:" + addr;
  
      addr = addr.replace(/./g, function(ch) {
          if (ch == "@") {
                 // this *must* be encoded. I insist.
              ch = encode[Math.floor(Math.random()*2)](ch);
          } else if (ch !=":") {
              // leave ':' alone (to spot mailto: later)
              var r = Math.random();
              // roughly 10% raw, 45% hex, 45% dec
              ch =  (
                      r > .9  ?    encode[2](ch)   :
                      r > .45 ?    encode[1](ch)   :
                                  encode[0](ch)
                  );
          }
          return ch;
      });
  
      addr = "<a href=\"" + addr + "\">" + addr + "</a>";
      addr = addr.replace(/">.+:/g,"\">"); // strip the mailto: from the visible part
  
      return addr;
  }
  
  
  var _UnescapeSpecialChars = function(text) {
  //
  // Swap back in all the special characters we've hidden.
  //
      text = text.replace(/~E(\d+)E/g,
          function(wholeMatch,m1) {
              var charCodeToReplace = parseInt(m1);
              return String.fromCharCode(charCodeToReplace);
          }
      );
      return text;
  }
  
  
  var _Outdent = function(text) {
  //
  // Remove one level of line-leading tabs or spaces
  //
  
      // attacklab: hack around Konqueror 3.5.4 bug:
      // "----------bug".replace(/^-/g,"") == "bug"
  
      text = text.replace(/^(\t|[ ]{1,4})/gm,"~0"); // attacklab: g_tab_width
  
      // attacklab: clean up hack
      text = text.replace(/~0/g,"")
  
      return text;
  }
  
  var _Detab = function(text) {
  // attacklab: Detab's completely rewritten for speed.
  // In perl we could fix it by anchoring the regexp with \G.
  // In javascript we're less fortunate.
  
      // expand first n-1 tabs
      text = text.replace(/\t(?=\t)/g,"    "); // attacklab: g_tab_width
  
      // replace the nth with two sentinels
      text = text.replace(/\t/g,"~A~B");
  
      // use the sentinel to anchor our regex so it doesn't explode
      text = text.replace(/~B(.+?)~A/g,
          function(wholeMatch,m1,m2) {
              var leadingText = m1;
              var numSpaces = 4 - leadingText.length % 4;  // attacklab: g_tab_width
  
              // there *must* be a better way to do this:
              for (var i=0; i<numSpaces; i++) leadingText+=" ";
  
              return leadingText;
          }
      );
  
      // clean up sentinels
      text = text.replace(/~A/g,"    ");  // attacklab: g_tab_width
      text = text.replace(/~B/g,"");
  
      return text;
  }
  
  
  //
  //  attacklab: Utility functions
  //
  
  
  var escapeCharacters = function(text, charsToEscape, afterBackslash) {
      // First we have to escape the escape characters so that
      // we can build a character class out of them
      var regexString = "([" + charsToEscape.replace(/([\[\]\\])/g,"\\$1") + "])";
  
      if (afterBackslash) {
          regexString = "\\\\" + regexString;
      }
  
      var regex = new RegExp(regexString,"g");
      text = text.replace(regex,escapeCharacters_callback);
  
      return text;
  }
  
  
  var escapeCharacters_callback = function(wholeMatch,m1) {
      var charCodeToEscape = m1.charCodeAt(0);
      return "~E"+charCodeToEscape+"E";
  }
  
  } // end of Showdown.converter
  
  
  // export
  if (typeof module !== 'undefined') module.exports = Showdown;
  
  // stolen from AMD branch of underscore
  // AMD define happens at the end for compatibility with AMD loaders
  // that don't enforce next-turn semantics on modules.
  if (typeof define === 'function' && define.amd) {
      define('showdown', function() {
          return Showdown;
      });
  }
  