time-to-botec

markdown.js (43359B)

---

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