showdown.js

steal(function() {
	//
	// 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 = {};

	//
	// converter
	//
	// Wraps all "globals" so that the only thing
	// exposed is makeHtml().
	//
	Showdown.converter = function() {

		//
		// 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;


		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();

			// 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, "~");

			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);

			// 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>" + _RunSpanGamut(m1) + "</h1>");
			});

			text = text.replace(/^(.+)[ \t]*\n-+[ \t]*\n+/gm, function( matchFound, m1 ) {
				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;
				return hashBlock("<h" + h_level + ">" + _RunSpanGamut(m2) + "</h" + h_level + ">");
			});

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

	} // end of Showdown.converter
	return  new Showdown.converter();
})