showdown.js

//
// showdown.js -- A javascript port of Markdown.
//
// Modifications
// Copyright (c) 2011 Chris Spencer
// 
// PHP Markdown Extra
// Copyright (c) 2009 Michel Fortin
//
// node-markdown
// Copyright (c) 2010 Andris Reinman
// 
// Original showdown.js
// 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 = {};

//
// converter
//
// Wraps all "globals" so that the only thing
// exposed is makeHtml().
//
// accepts an array of config options that will merge with the config array below
Showdown.converter = function() {

//
// Globals:
//

// Global hashes, used by various utility routines
var g_urls;
var g_titles;
var g_html_blocks;
var g_print_refs;
var g_print_refs_count;

// Used to track when we're inside an ordered or unordered list
// (see _ProcessListItems() for details):
var g_list_level = 0;

var config = this.config = {
  stripHTML: false,
  headerautoid: false,
  tables: false,
  math: false,
  figures: false,
  refprint: false,
  github_flavouring: false,
  additional_parser: false
}

// loop through each argument passed and set it as a config option
if (arguments[0]) {
  for (x in arguments[0]) {
    this.config[x] = arguments[0][x];
  }
}

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 = new Array();
  g_titles = new Array();
  g_html_blocks = new Array();
  g_print_refs = {};
  g_print_refs_count = 0;

  // 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,"");

  // 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,"~");
  
  if (config.stripHTML) {
    text = stripUnwantedHTML(text);
  }
  
  if (config.refprint && g_print_refs_count) {
    var link_table = '<ul class="reflist print">';
    for (i in g_print_refs) {
      link_table += '<li>[' + g_print_refs[i] + ']: ' + i + '</li>'
    }
    link_table += '</ul>';
    text += link_table;
  }
  
  if (typeof config.additional_parser == 'function') {
    text = config.additional_parser(text);
  }


  return 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(){...});
  */
  var text = text.replace(/^[ ]{0,3}\[(.+)\]:[ \t]*\n?[ \t]*<?(\S+?)>?[ \t]*\n?[ \t]*(?:(\n*)["(](.+?)[")][ \t]*)?(?:\n+|\Z)/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 "";
    }
  );

  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"
  var block_tags_b = "p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|script|noscript|form|fieldset|iframe|math"

  // 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)\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);
  
  // Escape pipes early for tables.
  text = text.replace(/\\([\|])/g,escapeCharacters_callback);
  
  if (config.tables) {
    text = _DoTables(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 = _DoTextStyle(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
          (?:[^\(]*?\([^\)]*?\)\S*?)  // Match one depth of parentheses
          |
          (?:.*?) // Match no parentheses
        )
      >?        
      [ \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]*()<?((?:[^\(]*?\([^\)]*?\)\S*?)|(?:.*?))>?[ \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>";
  
  if (config.refprint) {
    if (!g_print_refs[url]) {
      g_print_refs[url] = ++g_print_refs_count;
    }
    result += '<span class="linkref print">~E91E' + g_print_refs[url] + '~E93E</span>';
  }
  
  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
      <?
        (         // src url = $4
          (?:[^\(]*?\([^\)]*?\)\S*?)  // Match one depth of parentheses
          |
          (?:\S+?)  // Match 0 depth of parentheses
        )
      >?      
      [ \t]*
      (          // $5
        (['"])      // quote char = $6
        (.*?)      // title = $7
        \6        // matching quote
        [ \t]*
      )?          // title is optional
    \)
    )
    /g,writeImageTag);
  */
  text = text.replace(/(![<>]?\[(.*?)\]\s?\([ \t]*()<?((?:[^\(]*?\([^\)]*?\)\S*?)|(?:\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 == "" && link_id !== "") {
    // lower-case and turn embedded newlines into spaces
    if (g_urls[link_id] != undefined) {
      url = g_urls[link_id];
      if (g_titles[link_id] != undefined) {
        title = g_titles[link_id];
      } else {
        title = undefined;
      }
    }
  }
  
  var figure = false, match;
  if (match = whole_match.match(/^!([<>])/)) {
    if (match[1] === ">") {
      figure = "right";
    } else if (match[1] === "<") {
      figure = "left";
    }
  }
  
  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 !== undefined) {
    title = title.replace(/"/g,"&quot;");
    title = escapeCharacters(title,"*_");
    result +=  " title=\"" + title + "\"";
  }
  
  result += " />";
  
  if (config.figures && figure !== false) {
    if (title === undefined || title === "") {
      result = '<div class="figure ' + figure + '">\n  ' + result + '\n</div>';
    } else {
      result = '<div class="figure ' + figure + '">\n  ' + result +
        '<br/>\n  <span>' + title + '</span>\n</div>';
    }
  }
  
  return result;
}


var _DoHeaders = function(text) {

  // Setext-style headers:
  //  Header 1
  //  ========
  //  
  //  Header 2
  //  --------
  //
  text = text.replace(/^(.+)[ \t]*\n=+[ \t]*\n+/gm,
    function(wholeMatch,m1) {
      if (config.headerautoid) {
        return hashBlock('<h1 id="' + headerId(m1) + '">' + _RunSpanGamut(m1) + "</h1>");
      } else {
        return hashBlock('<h1>' + _RunSpanGamut(m1) + "</h1>");
      }
    }
  );

  text = text.replace(/^(.+)[ \t]*\n-+[ \t]*\n+/gm,
    function(matchFound,m1) {
      if (config.headerautoid) {
        return hashBlock('<h2 id="' + headerId(m1) + '">' + _RunSpanGamut(m1) + "</h2>");
      } else {
        return hashBlock('<h2>' + _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;
      if (config.headerautoid) {
        return hashBlock("<h" + h_level + ' id="' + headerId(m2) + '">' + _RunSpanGamut(m2) + "</h" + h_level + ">");
      } else {
        return hashBlock("<h" + h_level + '>' + _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+">\n" + 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(/<\/li></g, "</li>\n<");
  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";
  
  if (config.github_flavouring) {  
    text = text.replace(/\n```([a-zA-Z]+)?\s*\n((?:.*\n+)+?)(\n*```|(?=~0))/g,
      function (wholeMatch, m1, m2) {
        var codeblock = _EncodeCode(m2);
        codeblock = _Detab(codeblock);
        codeblock = codeblock.replace(/^\n+/g,""); // trim leading newlines
        codeblock = codeblock.replace(/\n+$/g,""); // trim trailing whitespace
      
        if (m1) {
          codeblock = "<pre><code class=\"" + m1 + "\">" + codeblock + "\n</code></pre>";
        } else {
          codeblock = "<pre><code>" + codeblock + "\n</code></pre>";
        }
        return hashBlock(codeblock);
      });
  }
  
  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 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>";
    });
    
  if (config.math) {
    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+'<span class="mathInline">%%'+c+"%%</span>";
      });

    text = text.replace(/(^|[^\\])(~D~D)([^\r]*?[^~])\2(?!~D)/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+'<span class="math">~D~D'+c+"~D~D</span>";
      });
  }

  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;");

  // Pipes are escaped early, unescape them into escaped pipes.
  // Need to find better solution.
  text = text.replace(/~E124E/g, "\\|");
  
  // 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 _DoTextStyle = function(text) {

  // <strong> must go first:
  text = text.replace(/(\*\*|__)(?=\S)([^\r]*?\S[*_]*)\1/g,
    "<strong>$2</strong>");

  if (config.github_flavouring) {
    text = text.replace(/(\w)_(\w)/g, "$1~E95E$2") // ** GFM **  "~E95E" == escaped "_"
  }

  text = text.replace(/(~T~T)(?=\S)([^\r]*?\S[*_]*)\1/g,	"<del>$2</del>");

  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 = new Array();

  //
  // 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);
      if (config.github_flavouring) {
        str = str.replace(/\n/g,"<br />");  // ** GFM **
      }
      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>
//

  // attacklab: why can't javascript speak hex?
  function char2hex(ch) {
    var hexDigits = '0123456789ABCDEF';
    var dec = ch.charCodeAt(0);
    return(hexDigits.charAt(dec>>4) + hexDigits.charAt(dec&15));
  }

  var encode = [
    function(ch){return "&#"+ch.charCodeAt(0)+";";},
    function(ch){return "&#x"+char2hex(ch)+";";},
    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 doTrim = function(str) {
  if (str.trim !== undefined) {
    return str.trim();
  } else if (typeof jQuery !== 'undefined') {
    return $.trim(str);
  } else {
    return str.replace(/^\s\s*/, '').replace(/\s\s*$/, '');
  }
}

var escapeCharacters_callback = function(wholeMatch,m1) {
  var charCodeToEscape = m1.charCodeAt(0);
  return "~E"+charCodeToEscape+"E";
}

//
// Markdown Extra ported functions
//

var _DoTables = function (text) {
//
// Form HTML tables.
//
  //
  // Find tables with leading pipe.
  //
  //  | Header 1 | Header 2
  //  | -------- | --------
  //  | Cell 1   | Cell 2
  //  | Cell 3   | Cell 4
  //
  /*$text = preg_replace_callback('
    {
      ^              # Start of a line
      [ ]{0,3}  # Allowed whitespace.
      [|]              # Optional leading pipe (present)
      (.+) \n            # $1: Header row (at least one pipe)
      
      [ ]{0,3}  # Allowed whitespace.
      [|] ([ ]*[-:]+[-| :]*) \n  # $2: Header underline
      
      (              # $3: Cells
        (?>
          [ ]*        # Allowed whitespace.
          [|] .* \n      # Row content.
        )*
      )
      (?=\n|\Z)          # Stop at final double newline.
    }xm',
    array(&$this, '_doTable_leadingPipe_callback'), $text);*/
  
  text = text.replace(/^[ ]{0,3}[|](.+)\n[ ]{0,3}[|]([ ]*[-:]+[-| :]*)\n(((?=([ ]*[|].*\n))(?:[ ]*[|].*\n))*)(?=\n)/gm,
    _doTable_leadingPipe_callback);
  
  //
  // Find tables without leading pipe.
  //
  //  Header 1 | Header 2
  //  -------- | --------
  //  Cell 1   | Cell 2
  //  Cell 3   | Cell 4
  //
  /*
  $text = preg_replace_callback('
    {
      ^              # Start of a line
      [ ]{0,'.$less_than_tab.'}  # Allowed whitespace.
      (\S.*[|].*) \n        # $1: Header row (at least one pipe)
      
      [ ]{0,'.$less_than_tab.'}  # Allowed whitespace.
      ([-:]+[ ]*[|][-| :]*) \n  # $2: Header underline
      
      (              # $3: Cells
        (?>
          .* [|] .* \n    # Row content
        )*
      )
      (?=\n|\Z)          # Stop at final double newline.
    }xm',
    array(&$this, '_DoTable_callback'), $text);*/
  text = text.replace(/^[ ]{0,3}(\S.*[|].*)\n[ ]{0,3}([ ]*[-:]+[-| :]*)\n(((?=(.*[|].*\n))(?:.*[|].*\n))*)(?=\n)/gm,
    _doTable_callback);

  return text;
}
var _doTable_leadingPipe_callback = function () {
  var content = arguments[3];
  
  // Remove leading pipe for each row.
  content = content.replace(/^[ ]*[|]/gm, '');
  
  return _doTable_callback(arguments[0], arguments[1], arguments[2], content);
}
var _doTable_callback = function () {
  var head       = arguments[1];
  var underline  = arguments[2];
  var content    = arguments[3];

  // Remove any tailing pipes for each line.
  head       = head.replace(/[|][ ]*$/gm, '\n');
  underline  = underline.replace(/[|][ ]*\n/gm, '\n');
  content    = doTrim(content.replace(/[|][ ]*\n/gm, '\n'));
  
  // Reading alignement from header underline.
  var separators = underline.split(/[ ]*[|][ ]*/);
  var attr = {};
  for (var i = 0, len = separators.length; i < len; ++i) {
    if (separators[i].match(/^[ ]*[-]+:[ ]*$/))       attr[i] = ' align="right"';
    else if (separators[i].match(/^[ ]*:[-]+:[ ]*$/)) attr[i] = ' align="center"';
    else if (separators[i].match(/^[ ]*:[-]+[ ]*$/))  attr[i] = ' align="left"';
    else                                              attr[i] = '';
  }
  
  // Parsing span elements, including code spans, character escapes, 
  // and inline HTML tags, so that pipes inside those gets ignored.
  // head    = $this->parseSpan($head); // TODO
  var headers  = head.split(/[ ]*[|][ ]*/);
  var col_count = headers.length;
  
  // Write column headers.
  var text = "<table>\n";
  text += "<thead>\n";
  text += "<tr>\n";
  for (var i = 0; i < col_count; ++i) {
    text += "  <th"+attr[i]+">" + _RunSpanGamut(doTrim(headers[i])) + "</th>\n";
  }
  text += "</tr>\n";
  text += "</thead>\n";
  
  // Split content by row.
  var rows = content.split(/\n/);
  
  text += "<tbody>\n";
  for (var i = 0, len = rows.length; i < len; ++i) {
    // Parsing span elements, including code spans, character escapes, 
    // and inline HTML tags, so that pipes inside those gets ignored.
    // $row = $this->parseSpan($row); // TODO
    
    // Split row by cell.
    var row_cells = rows[i].split(/[ ]*[|][ ]*/);
    // row_cells = array_pad($row_cells, $col_count, '');  // TODO
    
    text += "<tr>\n";
    for (var j = 0, len2 = row_cells.length; j < len2; ++j) {
      text += "  <td"+attr[j]+">" + _RunSpanGamut(doTrim(row_cells[j])) + "</td>\n";
    }
    text += "</tr>\n";
  }
  text += "</tbody>\n";
  text += "</table>";
  
  return text;
}

} // end of Showdown.converter

// Sourced from https://github.com/andris9/node-markdown
var stripUnwantedHTML = function (html /*, allowedTags, allowedAttributes, forceProtocol */){
    var allowedTags = arguments[1] || 
            'a|b|blockquote|code|del|dd|dl|dt|em|h1|h2|h3|h4|h5|h6|'+
            'i|img|li|ol|p|pre|sup|sub|strong|strike|ul|br|hr|span|'+
            'table|th|tr|td|tbody|thead|tfoot|div',
        allowedAttributes = arguments[2] || {
            'img': 'src|width|height|alt',
            'a':   'href',
            '*':   'title',
            'span': 'class',
            'tr': 'rowspan',
            'td': 'colspan|align',
            'th': 'rowspan|align',
            'div': 'class',
            'code': 'class'
        }, forceProtocol = arguments[3] || true;
        
        testAllowed = new RegExp('^('+allowedTags.toLowerCase()+')$'),
        findTags = /<(\/?)\s*([\w:\-]+)([^>]*)>/g,
        findAttribs = /(\s*)([\w:-]+)\s*=\s*(?:(?:(["'])([^\3]+?)(?:\3))|([^\s]+))/g;
    
    // convert all strings patterns into regexp objects (if not already converted)
    for(var i in allowedAttributes){
        if(allowedAttributes.hasOwnProperty(i) && typeof allowedAttributes[i] === 'string'){
            allowedAttributes[i] = new RegExp('^('+
                allowedAttributes[i].toLowerCase()+')$');
        }
    }
    
    // find and match html tags
    return html.replace(findTags, function(original, lslash, tag, params){
        var tagAttr, wildcardAttr, 
            rslash = params.substr(-1)=="/" && "/" || "";

        tag = tag.toLowerCase();
        
        // tag is not allowed, return empty string
        if(!tag.match(testAllowed))
            return "";
        
        // tag is allowed
        else{
            // regexp objects for a particular tag
            tagAttr = tag in allowedAttributes && allowedAttributes[tag];
            wildcardAttr = "*" in allowedAttributes && allowedAttributes["*"];
            
            // if no attribs are allowed
            if(!tagAttr && !wildcardAttr)
                return "<"+lslash+tag+rslash+">";
            
            // remove trailing slash if any
            params = params.trim();
            if(rslash){
                params = params.substr(0, params.length-1);
            }
            
            // find and remove unwanted attributes
            params = params.replace(findAttribs, function(original, space,
                                                            name, quot, value){
                name = name.toLowerCase();
                
                if (!value && !quot) {
                  value = "";
                  quot = '"';
                } else if (!value) {
                  value = quot;
                  quot = '"';
                }
                
                // force data: and javascript: links and images to #
                if((name=="href" || name=="src") &&
                   (value.trim().substr(0, "javascript:".length)=="javascript:"
                    || (name == "href" && value.trim().substr(0, "data:".length)=="data:"))) {
                    value = "#";
                }
                
                // scope links and sources to http protocol
                if (forceProtocol &&
                     (name=="href" || name=="src") &&
                     !/^[a-zA-Z]{3,5}:\/\//.test(value) &&
                     (value.length < 8 && value.trim().substr(0, "&#x6D;&#97;&#105;&#108;&#116;&#111;:".length)=="&#x6D;&#97;&#105;&#108;&#116;&#111;:")) {
                  value = "http://" + value;
                }
                
                if((wildcardAttr && name.match(wildcardAttr)) ||
                        (tagAttr && name.match(tagAttr))){
                    return space+name+"="+quot+value+quot;
                }else
                    return "";
            });

            return "<"+lslash+tag+(params?" "+params:"")+rslash+">";
        }
            
    });
}

// export
if (typeof exports != 'undefined') exports.Showdown = Showdown;