//
// 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/>
//
// 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 Attacklab.showdown.converter();
//   var html = converter.makeHtml(text);
//
//   alert(html);
//
// Note: move the sample code to the bottom of this
// file before uncommenting it.
//


//
// Attacklab namespace
//
var Attacklab = Attacklab || {}

//
// Showdown namespace
//
Attacklab.showdown = Attacklab.showdown || {}

//
// converter
//
// Wraps all "globals" so that the only thing
// exposed is makeHtml().
//
Attacklab.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+)/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 Attacklab.showdown.converter


// Version 0.9 used the Showdown namespace instead of Attacklab.showdown
// The old namespace is deprecated, but we'll support it for now:
var Showdown = Attacklab.showdown;

// If anyone's interested, tell the world that this file's been loaded
if (Attacklab.fileLoaded) {
    Attacklab.fileLoaded("showdown.js");
}