From 36011ea1d2450f761fe6bddca02ff900e652c4b5 Mon Sep 17 00:00:00 2001
From: thepurpleblob <thepurpleblob>
Date: Thu, 8 Feb 2007 11:23:25 +0000
Subject: [PATCH] Latest, greatest version of Markdown processor.

---
 lib/markdown.php | 4050 +++++++++++++++++++++++++++-------------------
 1 file changed, 2400 insertions(+), 1650 deletions(-)

diff --git a/lib/markdown.php b/lib/markdown.php
index 9a1369cb41..0c2cfed85e 100755
--- a/lib/markdown.php
+++ b/lib/markdown.php
@@ -1,1214 +1,2250 @@
 <?php
-
 #
-# PHP Markdown Extra  -  A text-to-HTML conversion tool for web writers
+# Markdown Extra  -  A text-to-HTML conversion tool for web writers
 #
-# Copyright (c) 2004-2005 Michel Fortin  
+# PHP Markdown & Extra
+# Copyright (c) 2004-2007 Michel Fortin  
 # <http://www.michelf.com/projects/php-markdown/>
 #
-# Based on Markdown  
-# Copyright (c) 2004-2005 John Gruber  
+# Original Markdown
+# Copyright (c) 2004-2006 John Gruber  
 # <http://daringfireball.net/projects/markdown/>
 #
 
 
-global	$MarkdownPHPVersion, $MarkdownSyntaxVersion,
-		$md_empty_element_suffix, $md_tab_width,
-		$md_nested_brackets_depth, $md_nested_brackets, 
-		$md_escape_table, $md_backslash_escape_table, 
-		$md_list_level;
-
-$MarkdownPHPVersion    = 'Extra 1.0.1'; # Fri 9 Dec 2005
-$MarkdownSyntaxVersion = '1.0.1';  # Sun 12 Dec 2004
+define( 'MARKDOWN_VERSION',       "1.0.1f" ); # Wed 7 Feb 2007
+define( 'MARKDOWNEXTRA_VERSION',  "1.1.2" );  # Wed 7 Feb 2007
 
 
 #
 # Global default settings:
 #
-$md_empty_element_suffix = " />";     # Change to ">" for HTML output
-$md_tab_width = 4;
+
+# Change to ">" for HTML output
+define( 'MARKDOWN_EMPTY_ELEMENT_SUFFIX',  " />");
+
+# Define the width of a tab for code blocks.
+define( 'MARKDOWN_TAB_WIDTH',     4 );
+
+# Optional title attribute for footnote links and backlinks.
+define( 'MARKDOWN_FN_LINK_TITLE',         "" );
+define( 'MARKDOWN_FN_BACKLINK_TITLE',     "" );
+
+# Optional class attribute for footnote links and backlinks.
+define( 'MARKDOWN_FN_LINK_CLASS',         "" );
+define( 'MARKDOWN_FN_BACKLINK_CLASS',     "" );
+
 
 #
 # WordPress settings:
 #
-$md_wp_posts    = true;  # Set to false to remove Markdown from posts.
-$md_wp_comments = true;  # Set to false to remove Markdown from comments.
 
+# Change to false to remove Markdown from posts and/or comments.
+define( 'MARKDOWN_WP_POSTS',      true );
+define( 'MARKDOWN_WP_COMMENTS',   true );
+
+
+
+### Standard Function Interface ###
+
+define( 'MARKDOWN_PARSER_CLASS',  'MarkdownExtra_Parser' );
+
+function Markdown($text) {
+#
+# Initialize the parser and return the result of its transform method.
+#
+	# Setup static parser variable.
+	static $parser;
+	if (!isset($parser)) {
+		$parser_class = MARKDOWN_PARSER_CLASS;
+		$parser = new $parser_class;
+	}
+
+	# Transform text using parser.
+	return $parser->transform($text);
+}
+
+
+### WordPress Plugin Interface ###
 
-# -- WordPress Plugin Interface -----------------------------------------------
 /*
-Plugin Name: PHP Markdown Extra
+Plugin Name: Markdown Extra
 Plugin URI: http://www.michelf.com/projects/php-markdown/
 Description: <a href="http://daringfireball.net/projects/markdown/syntax">Markdown syntax</a> allows you to write using an easy-to-read, easy-to-write plain text format. Based on the original Perl version by <a href="http://daringfireball.net/">John Gruber</a>. <a href="http://www.michelf.com/projects/php-markdown/">More...</a>
-Version: Extra 1.0.1
+Version: 1.1.2
 Author: Michel Fortin
 Author URI: http://www.michelf.com/
 */
+
 if (isset($wp_version)) {
 	# More details about how it works here:
 	# <http://www.michelf.com/weblog/2005/wordpress-text-flow-vs-markdown/>
 	
 	# Post content and excerpts
-	if ($md_wp_posts) {
+	# - Remove WordPress paragraph generator.
+	# - Run Markdown on excerpt, then remove all tags.
+	# - Add paragraph tag around the excerpt, but remove it for the excerpt rss.
+	if (MARKDOWN_WP_POSTS) {
 		remove_filter('the_content',  'wpautop');
 		remove_filter('the_excerpt',  'wpautop');
 		add_filter('the_content',     'Markdown', 6);
 		add_filter('get_the_excerpt', 'Markdown', 6);
 		add_filter('get_the_excerpt', 'trim', 7);
-		add_filter('the_excerpt',     'md_add_p');
-		add_filter('the_excerpt_rss', 'md_strip_p');
+		add_filter('the_excerpt',     'mdwp_add_p');
+		add_filter('the_excerpt_rss', 'mdwp_strip_p');
 		
 		remove_filter('content_save_pre',  'balanceTags', 50);
 		remove_filter('excerpt_save_pre',  'balanceTags', 50);
 		add_filter('the_content',  	  'balanceTags', 50);
 		add_filter('get_the_excerpt', 'balanceTags', 9);
-		
-		function md_add_p($text) {
-			if (strlen($text) == 0) return;
-			if (strcasecmp(substr($text, -3), '<p>') == 0) return $text;
-			return '<p>'.$text.'</p>';
-		}
-		function md_strip_p($t) { return preg_replace('{</?[pP]>}', '', $t); }
 	}
 	
 	# Comments
-	if ($md_wp_comments) {
+	# - Remove WordPress paragraph generator.
+	# - Remove WordPress auto-link generator.
+	# - Scramble important tags before passing them to the kses filter.
+	# - Run Markdown on excerpt then remove paragraph tags.
+	if (MARKDOWN_WP_COMMENTS) {
 		remove_filter('comment_text', 'wpautop');
 		remove_filter('comment_text', 'make_clickable');
 		add_filter('pre_comment_content', 'Markdown', 6);
-		add_filter('pre_comment_content', 'md_hide_tags', 8);
-		add_filter('pre_comment_content', 'md_show_tags', 12);
+		add_filter('pre_comment_content', 'mdwp_hide_tags', 8);
+		add_filter('pre_comment_content', 'mdwp_show_tags', 12);
 		add_filter('get_comment_text',    'Markdown', 6);
 		add_filter('get_comment_excerpt', 'Markdown', 6);
-		add_filter('get_comment_excerpt', 'md_strip_p', 7);
+		add_filter('get_comment_excerpt', 'mdwp_strip_p', 7);
 	
-		global $md_hidden_tags;
-		$md_hidden_tags = array(
+		global $markdown_hidden_tags;
+		$markdown_hidden_tags = array(
 			'<p>'	=> md5('<p>'),		'</p>'	=> md5('</p>'),
 			'<pre>'	=> md5('<pre>'),	'</pre>'=> md5('</pre>'),
 			'<ol>'	=> md5('<ol>'),		'</ol>'	=> md5('</ol>'),
 			'<ul>'	=> md5('<ul>'),		'</ul>'	=> md5('</ul>'),
 			'<li>'	=> md5('<li>'),		'</li>'	=> md5('</li>'),
 			);
-		
-		function md_hide_tags($text) {
-			global $md_hidden_tags;
-			return str_replace(array_keys($md_hidden_tags), 
-								array_values($md_hidden_tags), $text);
-		}
-		function md_show_tags($text) {
-			global $md_hidden_tags;
-			return str_replace(array_values($md_hidden_tags), 
-								array_keys($md_hidden_tags), $text);
+	}
+	
+	function mdwp_add_p($text) {
+		if (!preg_match('{^$|^<(p|ul|ol|dl|pre|blockquote)>}i', $text)) {
+			$text = '<p>'.$text.'</p>';
+			$text = preg_replace('{\n{2,}}', "</p>\n\n<p>", $text);
 		}
+		return $text;
+	}
+	
+	function mdwp_strip_p($t) { return preg_replace('{</?p>}i', '', $t); }
+
+	function mdwp_hide_tags($text) {
+		global $markdown_hidden_tags;
+		return str_replace(array_keys($markdown_hidden_tags), 
+							array_values($markdown_hidden_tags), $text);
+	}
+	function mdwp_show_tags($text) {
+		global $markdown_hidden_tags;
+		return str_replace(array_values($markdown_hidden_tags), 
+							array_keys($markdown_hidden_tags), $text);
 	}
 }
 
 
-# -- bBlog Plugin Info --------------------------------------------------------
+### bBlog Plugin Info ###
+
 function identify_modifier_markdown() {
-	global $MarkdownPHPVersion;
 	return array(
-		'name'			=> 'markdown',
-		'type'			=> 'modifier',
-		'nicename'		=> 'PHP Markdown Extra',
-		'description'	=> 'A text-to-HTML conversion tool for web writers',
-		'authors'		=> 'Michel Fortin and John Gruber',
-		'licence'		=> 'GPL',
-		'version'		=> $MarkdownPHPVersion,
-		'help'			=> '<a href="http://daringfireball.net/projects/markdown/syntax">Markdown syntax</a> allows you to write using an easy-to-read, easy-to-write plain text format. Based on the original Perl version by <a href="http://daringfireball.net/">John Gruber</a>. <a href="http://www.michelf.com/projects/php-markdown/">More...</a>'
-	);
+		'name' => 'markdown',
+		'type' => 'modifier',
+		'nicename' => 'PHP Markdown Extra',
+		'description' => 'A text-to-HTML conversion tool for web writers',
+		'authors' => 'Michel Fortin and John Gruber',
+		'licence' => 'GPL',
+		'version' => MARKDOWNEXTRA_VERSION,
+		'help' => '<a href="http://daringfireball.net/projects/markdown/syntax">Markdown syntax</a> allows you to write using an easy-to-read, easy-to-write plain text format. Based on the original Perl version by <a href="http://daringfireball.net/">John Gruber</a>. <a href="http://www.michelf.com/projects/php-markdown/">More...</a>',
+		);
 }
 
-# -- Smarty Modifier Interface ------------------------------------------------
+
+### Smarty Modifier Interface ###
+
 function smarty_modifier_markdown($text) {
 	return Markdown($text);
 }
 
-# -- Textile Compatibility Mode -----------------------------------------------
-# Rename this file to "classTextile.php" and it can replace Textile anywhere.
+
+### Textile Compatibility Mode ###
+
+# Rename this file to "classTextile.php" and it can replace Textile everywhere.
+
 if (strcasecmp(substr(__FILE__, -16), "classTextile.php") == 0) {
 	# Try to include PHP SmartyPants. Should be in the same directory.
 	@include_once 'smartypants.php';
 	# Fake Textile class. It calls Markdown instead.
 	class Textile {
-		function TextileThis($text, $lite='', $encode='', $noimage='', $strict='') {
-			if ($lite == '' && $encode == '')   $text = Markdown($text);
-			if (function_exists('SmartyPants')) $text = SmartyPants($text);
+		function TextileThis($text, $lite='', $encode='') {
+			if ($lite == '' && $encode == '')    $text = Markdown($text);
+			if (function_exists('SmartyPants'))  $text = SmartyPants($text);
 			return $text;
 		}
+		# Fake restricted version: restrictions are not supported for now.
+		function TextileRestricted($text, $lite='', $noimage='') {
+			return $this->TextileThis($text, $lite);
+		}
+		# Workaround to ensure compatibility with TextPattern 4.0.3.
+		function blockLite($text) { return $text; }
 	}
 }
 
 
 
 #
-# Globals:
+# Markdown Parser Class
 #
 
-# Regex to match balanced [brackets].
-# Needed to insert a maximum bracked depth while converting to PHP.
-$md_nested_brackets_depth = 6;
-$md_nested_brackets = 
-	str_repeat('(?>[^\[\]]+|\[', $md_nested_brackets_depth).
-	str_repeat('\])*', $md_nested_brackets_depth);
-
-# Table of hash values for escaped characters:
-$md_escape_table = array(
-	"\\" => md5("\\"),
-	"`" => md5("`"),
-	"*" => md5("*"),
-	"_" => md5("_"),
-	"{" => md5("{"),
-	"}" => md5("}"),
-	"[" => md5("["),
-	"]" => md5("]"),
-	"(" => md5("("),
-	")" => md5(")"),
-	">" => md5(">"),
-	"#" => md5("#"),
-	"+" => md5("+"),
-	"-" => md5("-"),
-	"." => md5("."),
-	"!" => md5("!"),
-	":" => md5(":"),
-	"|" => md5("|"),
-);
-# Create an identical table but for escaped characters.
-$md_backslash_escape_table;
-foreach ($md_escape_table as $key => $char)
-	$md_backslash_escape_table["\\$key"] = $char;
+class Markdown_Parser {
 
+	# Regex to match balanced [brackets].
+	# Needed to insert a maximum bracked depth while converting to PHP.
+	var $nested_brackets_depth = 6;
+	var $nested_brackets;
 
+	# Table of hash values for escaped characters:
+	var $escape_chars = '\`*_{}[]()>#+-.!';
+	var $escape_table = array();
+	var $backslash_escape_table = array();
 
-function Markdown($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):
-	global $md_urls, $md_titles, $md_html_blocks, $md_html_hashes;
-	$md_urls = array();
-	$md_titles = array();
-	$md_html_blocks = array();
-	$md_html_hashes = array();
+	# Change to ">" for HTML output.
+	var $empty_element_suffix = MARKDOWN_EMPTY_ELEMENT_SUFFIX;
+	var $tab_width = MARKDOWN_TAB_WIDTH;
 
-	# Standardize line endings:
-	#   DOS to Unix and Mac to Unix
-	$text = str_replace(array("\r\n", "\r"), "\n", $text);
 
-	# Make sure $text ends with a couple of newlines:
-	$text .= "\n\n";
+	function Markdown_Parser() {
+	#
+	# Constructor function. Initialize appropriate member variables.
+	#
+		$this->_initDetab();
+	
+		$this->nested_brackets = 
+			str_repeat('(?>[^\[\]]+|\[', $this->nested_brackets_depth).
+			str_repeat('\])*', $this->nested_brackets_depth);
+		
+		# Create an identical table but for escaped characters.
+		foreach (preg_split('/(?!^|$)/', $this->escape_chars) as $char) {
+			$hash = md5($char);
+			$this->escape_table[$char] = $hash;
+			$this->backslash_escape_table["\\$char"] = $hash;
+		}
+		
+		# Sort document, block, and span gamut in ascendent priority order.
+		asort($this->document_gamut);
+		asort($this->block_gamut);
+		asort($this->span_gamut);
+	}
 
-	# Convert all tabs to spaces.
-	$text = _Detab($text);
 
-	# Turn block-level HTML blocks into hash entries
-	$text = _HashHTMLBlocks($text);
+	# Internal hashes used during transformation.
+	var $urls = array();
+	var $titles = array();
+	var $html_blocks = array();
+	var $html_hashes = array(); # Contains both blocks and span hashes.
 
-	# 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+/ .
-	$text = preg_replace('/^[ \t]+$/m', '', $text);
 
-	# Strip link definitions, store in hashes.
-	$text = _StripLinkDefinitions($text);
+	function transform($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):
+		$this->urls = array();
+		$this->titles = array();
+		$this->html_blocks = array();
+		$this->html_hashes = array();
+
+		# Standardize line endings:
+		#   DOS to Unix and Mac to Unix
+		$text = str_replace(array("\r\n", "\r"), "\n", $text);
+
+		# Make sure $text ends with a couple of newlines:
+		$text .= "\n\n";
+
+		# Convert all tabs to spaces.
+		$text = $this->detab($text);
+
+		# Turn block-level HTML blocks into hash entries
+		$text = $this->hashHTMLBlocks($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+/ .
+		$text = preg_replace('/^[ \t]+$/m', '', $text);
+
+		# Run document gamut methods.
+		foreach ($this->document_gamut as $method => $priority) {
+			$text = $this->$method($text);
+		}
 
-	$text = _RunBlockGamut($text, FALSE);
+		return $text . "\n";
+	}
+	
+	var $document_gamut = array(
+		# Strip link definitions, store in hashes.
+		"stripLinkDefinitions" => 20,
+		
+		"runBasicBlockGamut"   => 30,
+		"unescapeSpecialChars" => 90,
+		);
 
-	$text = _UnescapeSpecialChars($text);
 
-	return $text . "\n";
-}
+	function stripLinkDefinitions($text) {
+	#
+	# Strips link definitions from text, stores the URLs and titles in
+	# hash references.
+	#
+		$less_than_tab = $this->tab_width - 1;
+
+		# Link defs are in the form: ^[id]: url "optional title"
+		$text = preg_replace_callback('{
+							^[ ]{0,'.$less_than_tab.'}\[(.+)\][ ]?:	# id = $1
+							  [ \t]*
+							  \n?				# maybe *one* newline
+							  [ \t]*
+							<?(\S+?)>?			# url = $2
+							  [ \t]*
+							  \n?				# maybe one newline
+							  [ \t]*
+							(?:
+								(?<=\s)			# lookbehind for whitespace
+								["(]
+								(.*?)			# title = $3
+								[")]
+								[ \t]*
+							)?	# title is optional
+							(?:\n+|\Z)
+			}xm',
+			array(&$this, '_stripLinkDefinitions_callback'),
+			$text);
+		return $text;
+	}
+	function _stripLinkDefinitions_callback($matches) {
+		$link_id = strtolower($matches[1]);
+		$this->urls[$link_id] = $this->encodeAmpsAndAngles($matches[2]);
+		if (isset($matches[3]))
+			$this->titles[$link_id] = str_replace('"', '&quot;', $matches[3]);
+		return ''; # String that will replace the block
+	}
 
 
-function _StripLinkDefinitions($text) {
-#
-# Strips link definitions from text, stores the URLs and titles in
-# hash references.
-#
-	global $md_tab_width;
-	$less_than_tab = $md_tab_width - 1;
-
-	# Link defs are in the form: ^[id]: url "optional title"
-	$text = preg_replace_callback('{
-						^[ ]{0,'.$less_than_tab.'}\[(.+)\]:	# id = $1
-						  [ \t]*
-						  \n?				# maybe *one* newline
-						  [ \t]*
-						<?(\S+?)>?			# url = $2
-						  [ \t]*
-						  \n?				# maybe one newline
-						  [ \t]*
-						(?:
-							(?<=\s)			# lookbehind for whitespace
-							["(]
-							(.+?)			# title = $3
-							[")]
-							[ \t]*
-						)?	# title is optional
-						(?:\n+|\Z)
-		}xm',
-		'_StripLinkDefinitions_callback',
-		$text);
-	return $text;
-}
-function _StripLinkDefinitions_callback($matches) {
-	global $md_urls, $md_titles;
-	$link_id = strtolower($matches[1]);
-	$md_urls[$link_id] = _EncodeAmpsAndAngles($matches[2]);
-	if (isset($matches[3]))
-		$md_titles[$link_id] = str_replace('"', '&quot;', $matches[3]);
-	return ''; # String that will replace the block
-}
+	function hashHTMLBlocks($text) {
+		$less_than_tab = $this->tab_width - 1;
+
+		# 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:
+		$block_tags_a = 'p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|address|'.
+						'script|noscript|form|fieldset|iframe|math|ins|del';
+		$block_tags_b = 'p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|address|'.
+						'script|noscript|form|fieldset|iframe|math';
+
+		# Regular expression for the content of a block tag.
+		$nested_tags_level = 4;
+		$attr = '
+			(?>				# optional tag attributes
+			  \s			# starts with whitespace
+			  (?>
+				[^>"/]+		# text outside quotes
+			  |
+				/+(?!>)		# slash not followed by ">"
+			  |
+				"[^"]*"		# text inside double quotes (tolerate ">")
+			  |
+				\'[^\']*\'	# text inside single quotes (tolerate ">")
+			  )*
+			)?	
+			';
+		$content =
+			str_repeat('
+				(?>
+				  [^<]+			# content without tag
+				|
+				  <\2			# nested opening tag
+					'.$attr.'	# attributes
+					(?:
+					  />
+					|
+					  >', $nested_tags_level).	# end of opening tag
+					  '.*?'.					# last level nested tag content
+			str_repeat('
+					  </\2\s*>	# closing nested tag
+					)
+				  |				
+					<(?!/\2\s*>	# other tags with a different name
+				  )
+				)*',
+				$nested_tags_level);
+
+		# 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>`.
+		$text = preg_replace_callback('{
+					(						# save in $1
+						^					# start of line  (with /m)
+						<('.$block_tags_a.')# start tag = $2
+						'.$attr.'>\n		# attributes followed by > and \n
+						'.$content.'		# content, support nesting
+						</\2>				# the matching end tag
+						[ \t]*				# trailing spaces/tabs
+						(?=\n+|\Z)	# followed by a newline or end of document
+					)
+			}xm',
+			array(&$this, '_hashHTMLBlocks_callback'),
+			$text);
 
+		#
+		# Match from `\n<tag>` to `</tag>\n`, handling nested tags in between.
+		#
+		$text = preg_replace_callback('{
+					(						# save in $1
+						^					# start of line  (with /m)
+						<('.$block_tags_b.')# start tag = $2
+						'.$attr.'>			# attributes followed by >
+						'.$content.'		# content, support nesting
+						</\2>				# the matching end tag
+						[ \t]*				# trailing spaces/tabs
+						(?=\n+|\Z)	# followed by a newline or end of document
+					)
+			}xm',
+			array(&$this, '_hashHTMLBlocks_callback'),
+			$text);
 
-function _HashHTMLBlocks($text) {
-#
-# Hashify HTML Blocks and "clean tags".
-#
-# 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.
-#
-# This works by calling _HashHTMLBlocks_InMarkdown, which then calls
-# _HashHTMLBlocks_InHTML when it encounter block tags. When the markdown="1" 
-# attribute is found whitin a tag, _HashHTMLBlocks_InHTML calls back
-#  _HashHTMLBlocks_InMarkdown to handle the Markdown syntax within the tag.
-# These two functions are calling each other. It's recursive!
-# 
-	global	$block_tags, $context_block_tags, $contain_span_tags, 
-			$clean_tags, $auto_close_tags;
-	
-	# Tags that are always treated as block tags:
-	$block_tags = 'p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|'.
-					'form|fieldset|iframe|hr|legend';
-	
-	# Tags treated as block tags only if the opening tag is alone on it's line:
-	$context_block_tags = 'script|noscript|math|ins|del';
-	
-	# Tags where markdown="1" default to span mode:
-	$contain_span_tags = 'p|h[1-6]|li|dd|dt|td|th|legend';
-	
-	# Tags which must not have their contents modified, no matter where 
-	# they appear:
-	$clean_tags = 'script|math';
-	
-	# Tags that do not need to be closed.
-	$auto_close_tags = 'hr|img';
-	
-	# Regex to match any tag.
-	global $tag_match;
-	$tag_match =
-		'{
-			(					# $2: Capture hole tag.
-				</?					# Any opening or closing tag.
-					[\w:$]+			# Tag name.
-					\s*				# Whitespace.
+		# Special case just for <hr />. It was easier to make a special case than
+		# to make the other regex more complicated.
+		$text = preg_replace_callback('{
 					(?:
-						".*?"		|	# Double quotes (can contain `>`)
-						\'.*?\'   	|	# Single quotes (can contain `>`)
-						.+?				# Anything but quotes and `>`.
-					)*?
-				>					# End of tag.
-			|
-				<!--    .*?     -->	# HTML Comment
-			|
-				<\?     .*?     \?>	# Processing instruction
-			|
-				<!\[CDATA\[.*?\]\]>	# CData Block
-			)
-		}xs';
-	
+						(?<=\n\n)		# Starting after a blank line
+						|				# or
+						\A\n?			# the beginning of the doc
+					)
+					(						# save in $1
+						[ ]{0,'.$less_than_tab.'}
+						<(hr)				# start tag = $2
+						\b					# word break
+						([^<>])*?			# 
+						/?>					# the matching end tag
+						[ \t]*
+						(?=\n{2,}|\Z)		# followed by a blank line or end of document
+					)
+			}x',
+			array(&$this, '_hashHTMLBlocks_callback'),
+			$text);
+
+		# Special case for standalone HTML comments:
+		$text = preg_replace_callback('{
+				(?:
+					(?<=\n\n)		# Starting after a blank line
+					|				# or
+					\A\n?			# the beginning of the doc
+				)
+				(						# save in $1
+					[ ]{0,'.$less_than_tab.'}
+					(?s:
+						<!-- .*? -->
+					)
+					[ \t]*
+					(?=\n{2,}|\Z)		# followed by a blank line or end of document
+				)
+			}x',
+			array(&$this, '_hashHTMLBlocks_callback'),
+			$text);
+
+		# PHP and ASP-style processor instructions (<? and <%)
+		$text = preg_replace_callback('{
+				(?:
+					(?<=\n\n)		# Starting after a blank line
+					|				# or
+					\A\n?			# the beginning of the doc
+				)
+				(						# save in $1
+					[ ]{0,'.$less_than_tab.'}
+					(?s:
+						<([?%])			# $2
+						.*?
+						\2>
+					)
+					[ \t]*
+					(?=\n{2,}|\Z)		# followed by a blank line or end of document
+				)
+			}x',
+			array(&$this, '_hashHTMLBlocks_callback'),
+			$text);
+
+		return $text;
+	}
+	function _hashHTMLBlocks_callback($matches) {
+		$text = $matches[1];
+		$key  = $this->hashBlock($text);
+		return "\n\n$key\n\n";
+	}
+
+
+	function hashBlock($text) {
 	#
-	# Call the HTML-in-Markdown hasher.
+	# Called whenever a tag must be hashed when a function insert a block-level 
+	# tag in $text, it pass through this function and is automaticaly escaped, 
+	# which remove the need to call _HashHTMLBlocks at every step.
 	#
-	list($text, ) = _HashHTMLBlocks_InMarkdown($text);
-	
-	return $text;
-}
-function _HashHTMLBlocks_InMarkdown($text, $indent = 0, 
-									$enclosing_tag = '', $md_span = false)
-{
-#
-# Parse markdown text, calling _HashHTMLBlocks_InHTML for block tags.
-#
-# *   $indent is the number of space to be ignored when checking for code 
-#     blocks. This is important because if we don't take the indent into 
-#     account, something like this (which looks right) won't work as expected:
-#
-#     <div>
-#         <div markdown="1">
-#         Hello World.  <-- Is this a Markdown code block or text?
-#         </div>  <-- Is this a Markdown code block or a real tag?
-#     <div>
-#
-#     If you don't like this, just don't indent the tag on which
-#     you apply the markdown="1" attribute.
-#
-# *   If $enclosing_tag is not empty, stops at the first unmatched closing 
-#     tag with that name. Nested tags supported.
-#
-# *   If $md_span is true, text inside must treated as span. So any double 
-#     newline will be replaced by a single newline so that it does not create 
-#     paragraphs.
-#
-# Returns an array of that form: ( processed text , remaining text )
-#
-	global	$block_tags, $context_block_tags, $clean_tags, $auto_close_tags,
-			$tag_match;
-	
-	if ($text === '') return array('', '');
-
-	# Regex to check for the presense of newlines around a block tag.
-	$newline_match_before = "/(?:^\n?|\n\n) *$/";
-	$newline_match_after = 
-		'{
-			^						# Start of text following the tag.
-			(?:[ ]*<!--.*?-->)?		# Optional comment.
-			[ ]*\n					# Must be followed by newline.
-		}xs';
-	
-	# Regex to match any tag.
-	$block_tag_match =
-		'{
-			(					# $2: Capture hole tag.
-				</?					# Any opening or closing tag.
-					(?:				# Tag name.
-						'.$block_tags.'			|
-						'.$context_block_tags.'	|
-						'.$clean_tags.'        	|
-						(?!\s)'.$enclosing_tag.'
-					)
-					\s*				# Whitespace.
-					(?:
-						".*?"		|	# Double quotes (can contain `>`)
-						\'.*?\'   	|	# Single quotes (can contain `>`)
-						.+?				# Anything but quotes and `>`.
-					)*?
-				>					# End of tag.
-			|
-				<!--    .*?     -->	# HTML Comment
-			|
-				<\?     .*?     \?>	# Processing instruction
-			|
-				<!\[CDATA\[.*?\]\]>	# CData Block
-			)
-		}xs';
+		# Swap back any tag hash found in $text so we do not have to `unhash`
+		# multiple times at the end.
+		$text = $this->unhash($text);
+		
+		# Then hash the block.
+		$key = md5($text);
+		$this->html_hashes[$key] = $text;
+		$this->html_blocks[$key] = $text;
+		return $key; # String that will replace the tag.
+	}
 
-	
-	$depth = 0;		# Current depth inside the tag tree.
-	$parsed = "";	# Parsed text that will be returned.
 
+	function hashSpan($text) {
 	#
-	# Loop through every tag until we find the closing tag of the parent
-	# or loop until reaching the end of text if no parent tag specified.
+	# Called whenever a tag must be hashed when a function insert a span-level 
+	# element in $text, it pass through this function and is automaticaly 
+	# escaped, blocking invalid nested overlap.
 	#
-	do {
-		#
-		# Split the text using the first $tag_match pattern found.
-		# Text before  pattern will be first in the array, text after
-		# pattern will be at the end, and between will be any catches made 
-		# by the pattern.
-		#
-		$parts = preg_split($block_tag_match, $text, 2, 
-							PREG_SPLIT_DELIM_CAPTURE);
+		# Swap back any tag hash found in $text so we do not have to `unhash`
+		# multiple times at the end.
+		$text = $this->unhash($text);
 		
-		# If in Markdown span mode, replace any multiple newlines that would 
-		# trigger a new paragraph.
-		if ($md_span) {
-			$parts[0] = preg_replace('/\n\n/', "\n", $parts[0]);
-		}
+		# Then hash the span.
+		$key = md5($text);
+		$this->html_hashes[$key] = $text;
+		return $key; # String that will replace the span tag.
+	}
+
+
+	var $block_gamut = array(
+	#
+	# These are all the transformations that form block-level
+	# tags like paragraphs, headers, and list items.
+	#
+		"doHeaders"         => 10,
+		"doHorizontalRules" => 20,
 		
-		$parsed .= $parts[0]; # Text before current tag.
+		"doLists"           => 40,
+		"doCodeBlocks"      => 50,
+		"doBlockQuotes"     => 60,
+		);
+
+	function runBlockGamut($text) {
+	#
+	# Run block gamut tranformations.
+	#
+		# We need to escape raw HTML in Markdown source before doing anything 
+		# else. This need to be done for each block, and not only at the 
+		# begining in the Markdown function since hashed blocks can be part of
+		# list items and could have been indented. Indented blocks would have 
+		# been seen as a code block in a previous pass of hashHTMLBlocks.
+		$text = $this->hashHTMLBlocks($text);
 		
-		# If end of $text has been reached. Stop loop.
-		if (count($parts) < 3) {
-			$text = "";
-			break;
+		return $this->runBasicBlockGamut($text);
+	}
+	
+	function runBasicBlockGamut($text) {
+	#
+	# Run block gamut tranformations, without hashing HTML blocks. This is 
+	# useful when HTML blocks are known to be already hashed, like in the first
+	# whole-document pass.
+	#
+		foreach ($this->block_gamut as $method => $priority) {
+			$text = $this->$method($text);
 		}
 		
-		$tag  = $parts[1]; # Tag to handle.
-		$text = $parts[2]; # Remaining text after current tag.
+		# Finally form paragraph and restore hashed blocks.
+		$text = $this->formParagraphs($text);
+
+		return $text;
+	}
+	
+	
+	function doHorizontalRules($text) {
+		# Do Horizontal Rules:
+		return preg_replace(
+			array('{^[ ]{0,2}([ ]?\*[ ]?){3,}[ \t]*$}mx',
+				  '{^[ ]{0,2}([ ]? -[ ]?){3,}[ \t]*$}mx',
+				  '{^[ ]{0,2}([ ]? _[ ]?){3,}[ \t]*$}mx'),
+			"\n".$this->hashBlock("<hr$this->empty_element_suffix")."\n", 
+			$text);
+	}
+
+
+	var $span_gamut = array(
+	#
+	# These are all the transformations that occur *within* block-level
+	# tags like paragraphs, headers, and list items.
+	#
+		"escapeSpecialCharsWithinTagAttributes"	=> -20,
+		"doCodeSpans"							=> -10,
+		"encodeBackslashEscapes"				=>  -5,
+
+		# Process anchor and image tags. Images must come first,
+		# because ![foo][f] looks like an anchor.
+		"doImages"            =>  10,
+		"doAnchors"           =>  20,
 		
-		#
-		# Check for: Tag inside code block or span
-		#
-		if (# Find current paragraph
-			preg_match('/(?>^\n?|\n\n)((?>.\n?)+?)$/', $parsed, $matches) &&
-			(
-			# Then match in it either a code block...
-			preg_match('/^ {'.($indent+4).'}.*(?>\n {'.($indent+4).'}.*)*'.
-						'(?!\n)$/', $matches[1], $x) ||
-			# ...or unbalenced code span markers. (the regex matches balenced)
-			!preg_match('/^(?>[^`]+|(`+)(?>[^`]+|(?!\1[^`])`)*?\1(?!`))*$/s',
-						 $matches[1])
-			))
-		{
-			# Tag is in code block or span and may not be a tag at all. So we
-			# simply skip the first char (should be a `<`).
-			$parsed .= $tag{0};
-			$text = substr($tag, 1) . $text; # Put back $tag minus first char.
+		# Make links out of things like `<http://example.com/>`
+		# Must come after doAnchors, because you can use < and >
+		# delimiters in inline links like [this](<url>).
+		"doAutoLinks"         =>  30,
+		"encodeAmpsAndAngles" =>  40,
+
+		"doItalicsAndBold"    =>  50,
+		"doHardBreaks"        =>  60,
+		);
+
+	function runSpanGamut($text) {
+	#
+	# Run span gamut tranformations.
+	#
+		foreach ($this->span_gamut as $method => $priority) {
+			$text = $this->$method($text);
+		}
+
+		return $text;
+	}
+	
+	
+	function doHardBreaks($text) {
+		# Do hard breaks:
+		$br_tag = $this->hashSpan("<br$this->empty_element_suffix\n");
+		return preg_replace('/ {2,}\n/', $br_tag, $text);
+	}
+
+
+	function escapeSpecialCharsWithinTagAttributes($text) {
+	#
+	# Within tags -- meaning between < and > -- encode [\ ` * _] so they
+	# don't conflict with their use in Markdown for code, italics and strong.
+	# We're replacing each such character with its corresponding MD5 checksum
+	# value; this is likely overkill, but it should prevent us from colliding
+	# with the escape values by accident.
+	#
+		$tokens = $this->tokenizeHTML($text);
+		$text = '';   # rebuild $text from the tokens
+
+		foreach ($tokens as $cur_token) {
+			if ($cur_token[0] == 'tag') {
+				$cur_token[1] = str_replace('\\', $this->escape_table['\\'], $cur_token[1]);
+				$cur_token[1] = str_replace(array('`'), $this->escape_table['`'], $cur_token[1]);
+				$cur_token[1] = str_replace('*', $this->escape_table['*'], $cur_token[1]);
+				$cur_token[1] = str_replace('_', $this->escape_table['_'], $cur_token[1]);
+			}
+			$text .= $cur_token[1];
 		}
+		return $text;
+	}
+
+
+	function doAnchors($text) {
+	#
+	# Turn Markdown link shortcuts into XHTML <a> tags.
+	#
 		#
-		# Check for: Opening Block level tag or
-		#            Opening Content Block tag (like ins and del) 
-		#               used as a block tag (tag is alone on it's line).
+		# First, handle reference-style links: [link text] [id]
 		#
-		else if (preg_match("{^<(?:$block_tags)\b}", $tag) ||
-			(	preg_match("{^<(?:$context_block_tags)\b}", $tag) &&
-				preg_match($newline_match_before, $parsed) &&
-				preg_match($newline_match_after, $text)	)
+		$text = preg_replace_callback('{
+			(					# wrap whole match in $1
+			  \[
+				('.$this->nested_brackets.')	# link text = $2
+			  \]
+
+			  [ ]?				# one optional space
+			  (?:\n[ ]*)?		# one optional newline followed by spaces
+
+			  \[
+				(.*?)		# id = $3
+			  \]
 			)
-		{
-			# Need to parse tag and following text using the HTML parser.
-			list($block_text, $text) = 
-				_HashHTMLBlocks_InHTML($tag . $text,
-									"_HashHTMLBlocks_HashBlock", TRUE);
-			
-			# Make sure it stays outside of any paragraph by adding newlines.
-			$parsed .= "\n\n$block_text\n\n";
-		}
+			}xs',
+			array(&$this, '_doAnchors_reference_callback'), $text);
+
 		#
-		# Check for: Clean tag (like script, math)
-		#            HTML Comments, processing instructions.
+		# Next, inline-style links: [link text](url "optional title")
 		#
-		else if (preg_match("{^<(?:$clean_tags)\b}", $tag) ||
-			$tag{1} == '!' || $tag{1} == '?')
-		{
-			# Need to parse tag and following text using the HTML parser.
-			# (don't check for markdown attribute)
-			list($block_text, $text) = 
-				_HashHTMLBlocks_InHTML($tag . $text, 
-									"_HashHTMLBlocks_HashClean", FALSE);
-			
-			$parsed .= $block_text;
-		}
+		$text = preg_replace_callback('{
+			(				# wrap whole match in $1
+			  \[
+				('.$this->nested_brackets.')	# link text = $2
+			  \]
+			  \(			# literal paren
+				[ \t]*
+				<?(.*?)>?	# href = $3
+				[ \t]*
+				(			# $4
+				  ([\'"])	# quote char = $5
+				  (.*?)		# Title = $6
+				  \5		# matching quote
+				  [ \t]*	# ignore any spaces/tabs between closing quote and )
+				)?			# title is optional
+			  \)
+			)
+			}xs',
+			array(&$this, '_DoAnchors_inline_callback'), $text);
+
 		#
-		# Check for: Tag with same name as enclosing tag.
+		# Last, handle reference-style shortcuts: [link text]
+		# These must come last in case you've also got [link test][1]
+		# or [link test](/foo)
 		#
-		else if ($enclosing_tag !== '' &&
-			# Same name as enclosing tag.
-			preg_match("{^</?(?:$enclosing_tag)\b}", $tag))
-		{
-			#
-			# Increase/decrease nested tag count.
-			#
-			if ($tag{1} == '/')						$depth--;
-			else if ($tag{strlen($tag)-2} != '/')	$depth++;
+//		$text = preg_replace_callback('{
+//			(					# wrap whole match in $1
+//			  \[
+//				([^\[\]]+)		# link text = $2; can\'t contain [ or ]
+//			  \]
+//			)
+//			}xs',
+//			array(&$this, '_doAnchors_reference_callback'), $text);
+
+		return $text;
+	}
+	function _doAnchors_reference_callback($matches) {
+		$whole_match =  $matches[1];
+		$link_text   =  $matches[2];
+		$link_id     =& $matches[3];
+
+		if ($link_id == "") {
+			# for shortcut links like [this][] or [this].
+			$link_id = $link_text;
+		}
+		
+		# lower-case and turn embedded newlines into spaces
+		$link_id = strtolower($link_id);
+		$link_id = preg_replace('{[ ]?\n}', ' ', $link_id);
 
-			if ($depth < 0) {
-				#
-				# Going out of parent element. Clean up and break so we
-				# return to the calling function.
-				#
-				$text = $tag . $text;
-				break;
-			}
+		if (isset($this->urls[$link_id])) {
+			$url = $this->urls[$link_id];
+			$url = $this->encodeAmpsAndAngles($url);
 			
-			$parsed .= $tag;
+			$result = "<a href=\"$url\"";
+			if ( isset( $this->titles[$link_id] ) ) {
+				$title = $this->titles[$link_id];
+				$title = $this->encodeAmpsAndAngles($title);
+				$result .=  " title=\"$title\"";
+			}
+		
+			$link_text = $this->runSpanGamut($link_text);
+			$result .= ">$link_text</a>";
+			$result = $this->hashSpan($result);
 		}
 		else {
-			$parsed .= $tag;
+			$result = $whole_match;
 		}
-	} while ($depth >= 0);
-	
-	return array($parsed, $text);
-}
-function _HashHTMLBlocks_InHTML($text, $hash_function, $md_attr) {
-#
-# Parse HTML, calling _HashHTMLBlocks_InMarkdown for block tags.
-#
-# *   Calls $hash_function to convert any blocks.
-# *   Stops when the first opening tag closes.
-# *   $md_attr indicate if the use of the `markdown="1"` attribute is allowed.
-#     (it is not inside clean tags)
-#
-# Returns an array of that form: ( processed text , remaining text )
-#
-	global $auto_close_tags, $contain_span_tags, $tag_match;
-	
-	if ($text === '') return array('', '');
-	
-	# Regex to match `markdown` attribute inside of a tag.
-	$markdown_attr_match = '
-		{
-			\s*			# Eat whitespace before the `markdown` attribute
-			markdown
-			\s*=\s*
-			(["\'])		# $1: quote delimiter		
-			(.*?)		# $2: attribute value
-			\1			# matching delimiter	
-		}xs';
-	
-	$original_text = $text;		# Save original text in case of faliure.
-	
-	$depth		= 0;	# Current depth inside the tag tree.
-	$block_text	= "";	# Temporary text holder for current text.
-	$parsed		= "";	# Parsed text that will be returned.
+		return $result;
+	}
+	function _doAnchors_inline_callback($matches) {
+		$whole_match	=  $matches[1];
+		$link_text		=  $this->runSpanGamut($matches[2]);
+		$url			=  $matches[3];
+		$title			=& $matches[6];
+		
+		$url = $this->encodeAmpsAndAngles($url);
 
-	#
-	# Get the name of the starting tag.
-	#
-	if (preg_match("/^<([\w:$]*)\b/", $text, $matches))
-		$base_tag_name = $matches[1];
+		$result = "<a href=\"$url\"";
+		if (isset($title)) {
+			$title = str_replace('"', '&quot;', $title);
+			$title = $this->encodeAmpsAndAngles($title);
+			$result .=  " title=\"$title\"";
+		}
+		
+		$link_text = $this->runSpanGamut($link_text);
+		$result .= ">$link_text</a>";
 
+		return $this->hashSpan($result);
+	}
+
+
+	function doImages($text) {
 	#
-	# Loop through every tag until we find the corresponding closing tag.
+	# Turn Markdown image shortcuts into <img> tags.
 	#
-	do {
 		#
-		# Split the text using the first $tag_match pattern found.
-		# Text before  pattern will be first in the array, text after
-		# pattern will be at the end, and between will be any catches made 
-		# by the pattern.
+		# First, handle reference-style labeled images: ![alt text][id]
 		#
-		$parts = preg_split($tag_match, $text, 2, PREG_SPLIT_DELIM_CAPTURE);
-		
-		if (count($parts) < 3) {
-			#
-			# End of $text reached with unbalenced tag(s).
-			# In that case, we return original text unchanged and pass the
-			# first character as filtered to prevent an infinite loop in the 
-			# parent function.
-			#
-			return array($original_text{0}, substr($original_text, 1));
-		}
-		
-		$block_text .= $parts[0]; # Text before current tag.
-		$tag         = $parts[1]; # Tag to handle.
-		$text        = $parts[2]; # Remaining text after current tag.
-		
+		$text = preg_replace_callback('{
+			(				# wrap whole match in $1
+			  !\[
+				('.$this->nested_brackets.')		# alt text = $2
+			  \]
+
+			  [ ]?				# one optional space
+			  (?:\n[ ]*)?		# one optional newline followed by spaces
+
+			  \[
+				(.*?)		# id = $3
+			  \]
+
+			)
+			}xs', 
+			array(&$this, '_doImages_reference_callback'), $text);
+
 		#
-		# Check for: Auto-close tag (like <hr/>)
-		#			 Comments and Processing Instructions.
+		# Next, handle inline images:  ![alt text](url "optional title")
+		# Don't forget: encode * and _
 		#
-		if (preg_match("{^</?(?:$auto_close_tags)\b}", $tag) ||
-			$tag{1} == '!' || $tag{1} == '?')
-		{
-			# Just add the tag to the block as if it was text.
-			$block_text .= $tag;
+		$text = preg_replace_callback('{
+			(				# wrap whole match in $1
+			  !\[
+				('.$this->nested_brackets.')		# alt text = $2
+			  \]
+			  \s?			# One optional whitespace character
+			  \(			# literal paren
+				[ \t]*
+				<?(\S+?)>?	# src url = $3
+				[ \t]*
+				(			# $4
+				  ([\'"])	# quote char = $5
+				  (.*?)		# title = $6
+				  \5		# matching quote
+				  [ \t]*
+				)?			# title is optional
+			  \)
+			)
+			}xs',
+			array(&$this, '_doImages_inline_callback'), $text);
+
+		return $text;
+	}
+	function _doImages_reference_callback($matches) {
+		$whole_match = $matches[1];
+		$alt_text    = $matches[2];
+		$link_id     = strtolower($matches[3]);
+
+		if ($link_id == "") {
+			$link_id = strtolower($alt_text); # for shortcut links like ![this][].
 		}
-		else {
-			#
-			# Increase/decrease nested tag count. Only do so if
-			# the tag's name match base tag's.
-			#
-			if (preg_match("{^</?$base_tag_name\b}", $tag)) {
-				if ($tag{1} == '/')						$depth--;
-				else if ($tag{strlen($tag)-2} != '/')	$depth++;
-			}
-			
-			#
-			# Check for `markdown="1"` attribute and handle it.
-			#
-			if ($md_attr && 
-				preg_match($markdown_attr_match, $tag, $attr_matches) &&
-				preg_match('/^(?:1|block|span)$/', $attr_matches[2]))
-			{
-				# Remove `markdown` attribute from opening tag.
-				$tag = preg_replace($markdown_attr_match, '', $tag);
-				
-				# Check if text inside this tag must be parsed in span mode.
-				$md_mode = $attr_matches[2];
-				$span_mode = $md_mode == 'span' || $md_mode != 'block' &&
-							preg_match("{^<(?:$contain_span_tags)\b}", $tag);
-				
-				# Calculate indent before tag.
-				preg_match('/(?:^|\n)( *?)(?! ).*?$/', $block_text, $matches);
-				$indent = strlen($matches[1]);
-				
-				# End preceding block with this tag.
-				$block_text .= $tag;
-				$parsed .= $hash_function($block_text, $span_mode);
-				
-				# Get enclosing tag name for the ParseMarkdown function.
-				preg_match('/^<([\w:$]*)\b/', $tag, $matches);
-				$tag_name = $matches[1];
-				
-				# Parse the content using the HTML-in-Markdown parser.
-				list ($block_text, $text)
-					= _HashHTMLBlocks_InMarkdown($text, $indent, 
-													$tag_name, $span_mode);
-				
-				# Outdent markdown text.
-				if ($indent > 0) {
-					$block_text = preg_replace("/^[ ]{1,$indent}/m", "", 
-												$block_text);
-				}
-				
-				# Append tag content to parsed text.
-				if (!$span_mode)	$parsed .= "\n\n$block_text\n\n";
-				else				$parsed .= "$block_text";
-				
-				# Start over a new block.
-				$block_text = "";
+
+		$alt_text = str_replace('"', '&quot;', $alt_text);
+		if (isset($this->urls[$link_id])) {
+			$url = $this->urls[$link_id];
+			$result = "<img src=\"$url\" alt=\"$alt_text\"";
+			if (isset($this->titles[$link_id])) {
+				$title = $this->titles[$link_id];
+				$result .=  " title=\"$title\"";
 			}
-			else $block_text .= $tag;
+			$result .= $this->empty_element_suffix;
+			$result = $this->hashSpan($result);
 		}
+		else {
+			# If there's no such link ID, leave intact:
+			$result = $whole_match;
+		}
+
+		return $result;
+	}
+	function _doImages_inline_callback($matches) {
+		$whole_match	= $matches[1];
+		$alt_text		= $matches[2];
+		$url			= $matches[3];
+		$title			=& $matches[6];
+
+		$alt_text = str_replace('"', '&quot;', $alt_text);
+		$result = "<img src=\"$url\" alt=\"$alt_text\"";
+		if (isset($title)) {
+			$title = str_replace('"', '&quot;', $title);
+			$result .=  " title=\"$title\""; # $title already quoted
+		}
+		$result .= $this->empty_element_suffix;
+
+		return $this->hashSpan($result);
+	}
+
+
+	function doHeaders($text) {
+		# Setext-style headers:
+		#	  Header 1
+		#	  ========
+		#  
+		#	  Header 2
+		#	  --------
+		#
+		$text = preg_replace_callback('{ ^(.+)[ \t]*\n=+[ \t]*\n+ }mx',
+			array(&$this, '_doHeaders_callback_setext_h1'), $text);
+		$text = preg_replace_callback('{ ^(.+)[ \t]*\n-+[ \t]*\n+ }mx',
+			array(&$this, '_doHeaders_callback_setext_h2'), $text);
+
+		# atx-style headers:
+		#	# Header 1
+		#	## Header 2
+		#	## Header 2 with closing hashes ##
+		#	...
+		#	###### Header 6
+		#
+		$text = preg_replace_callback('{
+				^(\#{1,6})	# $1 = string of #\'s
+				[ \t]*
+				(.+?)		# $2 = Header text
+				[ \t]*
+				\#*			# optional closing #\'s (not counted)
+				\n+
+			}xm',
+			array(&$this, '_doHeaders_callback_atx'), $text);
+
+		return $text;
+	}
+	function _doHeaders_callback_setext_h1($matches) {
+		$block = "<h1>".$this->runSpanGamut($matches[1])."</h1>";
+		return "\n" . $this->hashBlock($block) . "\n\n";
+	}
+	function _doHeaders_callback_setext_h2($matches) {
+		$block = "<h2>".$this->runSpanGamut($matches[1])."</h2>";
+		return "\n" . $this->hashBlock($block) . "\n\n";
+	}
+	function _doHeaders_callback_atx($matches) {
+		$level = strlen($matches[1]);
+		$block = "<h$level>".$this->runSpanGamut($matches[2])."</h$level>";
+		return "\n" . $this->hashBlock($block) . "\n\n";
+	}
+
+
+	function doLists($text) {
+	#
+	# Form HTML ordered (numbered) and unordered (bulleted) lists.
+	#
+		$less_than_tab = $this->tab_width - 1;
+
+		# Re-usable patterns to match list item bullets and number markers:
+		$marker_ul  = '[*+-]';
+		$marker_ol  = '\d+[.]';
+		$marker_any = "(?:$marker_ul|$marker_ol)";
+
+		$markers = array($marker_ul, $marker_ol);
+
+		foreach ($markers as $marker) {
+			# Re-usable pattern to match any entirel ul or ol list:
+			$whole_list = '
+				(								# $1 = whole list
+				  (								# $2
+					[ ]{0,'.$less_than_tab.'}
+					('.$marker.')				# $3 = first list item marker
+					[ \t]+
+				  )
+				  (?s:.+?)
+				  (								# $4
+					  \z
+					|
+					  \n{2,}
+					  (?=\S)
+					  (?!						# Negative lookahead for another list item marker
+						[ \t]*
+						'.$marker.'[ \t]+
+					  )
+				  )
+				)
+			'; // mx
+			
+			# We use a different prefix before nested lists than top-level lists.
+			# See extended comment in _ProcessListItems().
 		
-	} while ($depth > 0);
-	
+			if ($this->list_level) {
+				$text = preg_replace_callback('{
+						^
+						'.$whole_list.'
+					}mx',
+					array(&$this, '_doLists_callback'), $text);
+			}
+			else {
+				$text = preg_replace_callback('{
+						(?:(?<=\n)\n|\A\n?) # Must eat the newline
+						'.$whole_list.'
+					}mx',
+					array(&$this, '_doLists_callback'), $text);
+			}
+		}
+
+		return $text;
+	}
+	function _doLists_callback($matches) {
+		# Re-usable patterns to match list item bullets and number markers:
+		$marker_ul  = '[*+-]';
+		$marker_ol  = '\d+[.]';
+		$marker_any = "(?:$marker_ul|$marker_ol)";
+		
+		$list = $matches[1];
+		$list_type = preg_match("/$marker_ul/", $matches[3]) ? "ul" : "ol";
+		
+		$marker_any = ( $list_type == "ul" ? $marker_ul : $marker_ol );
+		
+		$list .= "\n";
+		$result = $this->processListItems($list, $marker_any);
+		
+		$result = $this->hashBlock("<$list_type>\n" . $result . "</$list_type>");
+		return "\n". $result ."\n\n";
+	}
+
+	var $list_level = 0;
+
+	function processListItems($list_str, $marker_any) {
 	#
-	# Hash last block text that wasn't processed inside the loop.
+	#	Process the contents of a single ordered or unordered list, splitting it
+	#	into individual list items.
 	#
-	$parsed .= $hash_function($block_text);
-	
-	return array($parsed, $text);
-}
-function _HashHTMLBlocks_HashBlock($text) {
-	global $md_html_hashes, $md_html_blocks;
-	$key = md5($text);
-	$md_html_hashes[$key] = $text;
-	$md_html_blocks[$key] = $text;
-	return $key; # String that will replace the tag.
-}
-function _HashHTMLBlocks_HashClean($text) {
-	global $md_html_hashes;
-	$key = md5($text);
-	$md_html_hashes[$key] = $text;
-	return $key; # String that will replace the clean tag.
-}
+		# The $this->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.".
+		
+		$this->list_level++;
+
+		# trim trailing blank lines:
+		$list_str = preg_replace("/\n{2,}\\z/", "\n", $list_str);
+
+		$list_str = preg_replace_callback('{
+			(\n)?							# leading line = $1
+			(^[ \t]*)						# leading whitespace = $2
+			('.$marker_any.') [ \t]+		# list marker = $3
+			((?s:.+?))						# list item text   = $4
+			(?:(\n+(?=\n))|\n)				# tailing blank line = $5
+			(?= \n* (\z | \2 ('.$marker_any.') [ \t]+))
+			}xm',
+			array(&$this, '_processListItems_callback'), $list_str);
+
+		$this->list_level--;
+		return $list_str;
+	}
+	function _processListItems_callback($matches) {
+		$item = $matches[4];
+		$leading_line =& $matches[1];
+		$leading_space =& $matches[2];
+		$tailing_blank_line =& $matches[5];
+
+		if ($leading_line || $tailing_blank_line || 
+			preg_match('/\n{2,}/', $item))
+		{
+			$item = $this->runBlockGamut($this->outdent($item)."\n");
+		}
+		else {
+			# Recursion for sub-lists:
+			$item = $this->doLists($this->outdent($item));
+			$item = preg_replace('/\n+$/', '', $item);
+			$item = $this->runSpanGamut($item);
+		}
 
+		return "<li>" . $item . "</li>\n";
+	}
 
-function _HashBlock($text) {
-#
-# Called whenever a tag must be hashed. When a function insert a block-level 
-# tag in $text, it pass through this function and is automaticaly escaped, 
-# which remove the need to call _HashHTMLBlocks at every step.
-#
-	# Swap back any tag hash found in $text so we do not have to _UnhashTags
-	# multiple times at the end. Must do this because of 
-	$text = _UnhashTags($text);
-	
-	# Then hash the block as normal.
-	return _HashHTMLBlocks_HashBlock($text);
-}
 
+	function doCodeBlocks($text) {
+	#
+	#	Process Markdown `<pre><code>` blocks.
+	#
+		$text = preg_replace_callback('{
+				(?:\n\n|\A)
+				(	            # $1 = the code block -- one or more lines, starting with a space/tab
+				  (?:
+					(?:[ ]{'.$this->tab_width.'} | \t)  # Lines must start with a tab or a tab-width of spaces
+					.*\n+
+				  )+
+				)
+				((?=^[ ]{0,'.$this->tab_width.'}\S)|\Z)	# Lookahead for non-space at line-start, or end of doc
+			}xm',
+			array(&$this, '_doCodeBlocks_callback'), $text);
+
+		return $text;
+	}
+	function _doCodeBlocks_callback($matches) {
+		$codeblock = $matches[1];
 
-function _RunBlockGamut($text, $hash_html_blocks = TRUE) {
-#
-# These are all the transformations that form block-level
-# tags like paragraphs, headers, and list items.
-#
-	if ($hash_html_blocks) {
-		# We need to escape raw HTML in Markdown source before doing anything 
-		# else. This need to be done for each block, and not only at the 
-		# begining in the Markdown function since hashed blocks can be part of
-		# a list item and could have been indented. Indented blocks would have 
-		# been seen as a code block in previous pass of _HashHTMLBlocks.
-		$text = _HashHTMLBlocks($text);
-	}
-
-	$text = _DoHeaders($text);
-	$text = _DoTables($text);
-
-	# Do Horizontal Rules:
-	global $md_empty_element_suffix;
-	$text = preg_replace(
-		array('{^[ ]{0,2}([ ]?\*[ ]?){3,}[ \t]*$}emx',
-			  '{^[ ]{0,2}([ ]? -[ ]?){3,}[ \t]*$}emx',
-			  '{^[ ]{0,2}([ ]? _[ ]?){3,}[ \t]*$}emx'),
-		"_HashBlock('\n<hr$md_empty_element_suffix\n')", 
-		$text);
-
-	$text = _DoLists($text);
-	$text = _DoDefLists($text);
-	$text = _DoCodeBlocks($text);
-	$text = _DoBlockQuotes($text);
-	$text = _FormParagraphs($text);
-
-	return $text;
-}
+		$codeblock = $this->encodeCode($this->outdent($codeblock));
+	//	$codeblock = $this->detab($codeblock);
+		# trim leading newlines and trailing whitespace
+		$codeblock = preg_replace(array('/\A\n+/', '/\n+\z/'), '', $codeblock);
 
+		$result = "\n\n".$this->hashBlock("<pre><code>" . $codeblock . "\n</code></pre>")."\n\n";
+
+		return $result;
+	}
 
-function _RunSpanGamut($text) {
-#
-# These are all the transformations that occur *within* block-level
-# tags like paragraphs, headers, and list items.
-#
-	global $md_empty_element_suffix;
 
-	$text = _DoCodeSpans($text);
+	function doCodeSpans($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 = preg_replace_callback('@
+				(?<!\\\)	# Character before opening ` can\'t be a backslash
+				(`+)		# $1 = Opening run of `
+				(.+?)		# $2 = The code block
+				(?<!`)
+				\1			# Matching closer
+				(?!`)
+			@xs',
+			array(&$this, '_doCodeSpans_callback'), $text);
+
+		return $text;
+	}
+	function _doCodeSpans_callback($matches) {
+		$c = $matches[2];
+		$c = preg_replace('/^[ \t]*/', '', $c); # leading whitespace
+		$c = preg_replace('/[ \t]*$/', '', $c); # trailing whitespace
+		$c = $this->encodeCode($c);
+		return $this->hashSpan("<code>$c</code>");
+	}
 
-	$text = _EscapeSpecialChars($text);
 
-	# Process anchor and image tags. Images must come first,
-	# because ![foo][f] looks like an anchor.
-	$text = _DoImages($text);
-	$text = _DoAnchors($text);
+	function encodeCode($_) {
+	#
+	# 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.
+		$_ = str_replace('&', '&amp;', $_);
 
-	# 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 the angle bracket song and dance:
+		$_ = str_replace(array('<',    '>'), 
+						 array('&lt;', '&gt;'), $_);
 
-	# Do hard breaks:
-	$text = preg_replace('/ {2,}\n/', "<br$md_empty_element_suffix\n", $text);
+		# Now, escape characters that are magic in Markdown:
+//		$_ = str_replace(array_keys($this->escape_table), 
+//						 array_values($this->escape_table), $_);
 
-	return $text;
-}
+		return $_;
+	}
 
 
-function _EscapeSpecialChars($text) {
-	global $md_escape_table;
-	$tokens = _TokenizeHTML($text);
-
-	$text = '';   # rebuild $text from the tokens
-#	$in_pre = 0;  # Keep track of when we're inside <pre> or <code> tags.
-#	$tags_to_skip = "!<(/?)(?:pre|code|kbd|script|math)[\s>]!";
-
-	foreach ($tokens as $cur_token) {
-		if ($cur_token[0] == 'tag') {
-			# Within tags, encode * and _ so they don't conflict
-			# with their use in Markdown for italics and strong.
-			# We're replacing each such character with its
-			# corresponding MD5 checksum value; this is likely
-			# overkill, but it should prevent us from colliding
-			# with the escape values by accident.
-			$cur_token[1] = str_replace(array('*', '_'),
-				array($md_escape_table['*'], $md_escape_table['_']),
-				$cur_token[1]);
-			$text .= $cur_token[1];
-		} else {
-			$t = $cur_token[1];
-			$t = _EncodeBackslashEscapes($t);
-			$text .= $t;
-		}
+	function doItalicsAndBold($text) {
+		# <strong> must go first:
+		$text = preg_replace_callback('{
+				(						# $1: Marker
+					(?<!\*\*) \* |		#     (not preceded by two chars of
+					(?<!__)   _			#      the same marker)
+				)
+				\1
+				(?=\S) 					# Not followed by whitespace 
+				(?!\1\1)				#   or two others marker chars.
+				(						# $2: Content
+					(?:
+						[^*_]+?			# Anthing not em markers.
+					|
+										# Balence any regular emphasis inside.
+						\1 (?=\S) .+? (?<=\S) \1
+					|
+						(?! \1 ) .		# Allow unbalenced * and _.
+					)+?
+				)
+				(?<=\S) \1\1			# End mark not preceded by whitespace.
+			}sx',
+			array(&$this, '_doItalicAndBold_strong_callback'), $text);
+		# Then <em>:
+		$text = preg_replace_callback(
+			'{ ( (?<!\*)\* | (?<!_)_ ) (?=\S) (?! \1) (.+?) (?<=\S) \1 }sx',
+			array(&$this, '_doItalicAndBold_em_callback'), $text);
+
+		return $text;
+	}
+	function _doItalicAndBold_em_callback($matches) {
+		$text = $matches[2];
+		$text = $this->runSpanGamut($text);
+		return $this->hashSpan("<em>$text</em>");
+	}
+	function _doItalicAndBold_strong_callback($matches) {
+		$text = $matches[2];
+		$text = $this->runSpanGamut($text);
+		return $this->hashSpan("<strong>$text</strong>");
 	}
-	return $text;
-}
 
 
-function _DoAnchors($text) {
-#
-# Turn Markdown link shortcuts into XHTML <a> tags.
-#
-	global $md_nested_brackets;
-	#
-	# First, handle reference-style links: [link text] [id]
-	#
-	$text = preg_replace_callback("{
-		(					# wrap whole match in $1
-		  \\[
-			($md_nested_brackets)	# link text = $2
-		  \\]
-
-		  [ ]?				# one optional space
-		  (?:\\n[ ]*)?		# one optional newline followed by spaces
-
-		  \\[
-			(.*?)		# id = $3
-		  \\]
-		)
-		}xs",
-		'_DoAnchors_reference_callback', $text);
-
-	#
-	# Next, inline-style links: [link text](url "optional title")
-	#
-	$text = preg_replace_callback("{
-		(				# wrap whole match in $1
-		  \\[
-			($md_nested_brackets)	# link text = $2
-		  \\]
-		  \\(			# literal paren
-			[ \\t]*
-			<?(.*?)>?	# href = $3
-			[ \\t]*
-			(			# $4
-			  (['\"])	# quote char = $5
-			  (.*?)		# Title = $6
-			  \\5		# matching quote
-			)?			# title is optional
-		  \\)
-		)
-		}xs",
-		'_DoAnchors_inline_callback', $text);
-
-	return $text;
-}
-function _DoAnchors_reference_callback($matches) {
-	global $md_urls, $md_titles, $md_escape_table;
-	$whole_match = $matches[1];
-	$link_text   = $matches[2];
-	$link_id     = strtolower($matches[3]);
-
-	if ($link_id == "") {
-		$link_id = strtolower($link_text); # for shortcut links like [this][].
-	}
-
-	if (isset($md_urls[$link_id])) {
-		$url = $md_urls[$link_id];
-		# We've got to encode these to avoid conflicting with italics/bold.
-		$url = str_replace(array('*', '_'),
-						   array($md_escape_table['*'], $md_escape_table['_']),
-						   $url);
-		$result = "<a href=\"$url\"";
-		if ( isset( $md_titles[$link_id] ) ) {
-			$title = $md_titles[$link_id];
-			$title = str_replace(array('*',     '_'),
-								 array($md_escape_table['*'], 
-									   $md_escape_table['_']), $title);
-			$result .=  " title=\"$title\"";
+	function doBlockQuotes($text) {
+		$text = preg_replace_callback('/
+			  (								# Wrap whole match in $1
+				(
+				  ^[ \t]*>[ \t]?			# ">" at the start of a line
+					.+\n					# rest of the first line
+				  (.+\n)*					# subsequent consecutive lines
+				  \n*						# blanks
+				)+
+			  )
+			/xm',
+			array(&$this, '_doBlockQuotes_callback'), $text);
+
+		return $text;
+	}
+	function _doBlockQuotes_callback($matches) {
+		$bq = $matches[1];
+		# trim one level of quoting - trim whitespace-only lines
+		$bq = preg_replace(array('/^[ \t]*>[ \t]?/m', '/^[ \t]+$/m'), '', $bq);
+		$bq = $this->runBlockGamut($bq);		# recurse
+
+		$bq = preg_replace('/^/m', "  ", $bq);
+		# These leading spaces cause problem with <pre> content, 
+		# so we need to fix that:
+		$bq = preg_replace_callback('{(\s*<pre>.+?</pre>)}sx', 
+			array(&$this, '_DoBlockQuotes_callback2'), $bq);
+
+		return "\n". $this->hashBlock("<blockquote>\n$bq\n</blockquote>")."\n\n";
+	}
+	function _doBlockQuotes_callback2($matches) {
+		$pre = $matches[1];
+		$pre = preg_replace('/^  /m', '', $pre);
+		return $pre;
+	}
+
+
+	function formParagraphs($text) {
+	#
+	#	Params:
+	#		$text - string to process with html <p> tags
+	#
+		# Strip leading and trailing lines:
+		$text = preg_replace(array('/\A\n+/', '/\n+\z/'), '', $text);
+
+		$grafs = preg_split('/\n{2,}/', $text, -1, PREG_SPLIT_NO_EMPTY);
+
+		#
+		# Wrap <p> tags.
+		#
+		foreach ($grafs as $key => $value) {
+			if (!isset( $this->html_blocks[$value] )) {
+				$value = $this->runSpanGamut($value);
+				$value = preg_replace('/^([ \t]*)/', "<p>", $value);
+				$value .= "</p>";
+				$grafs[$key] = $this->unhash($value);
+			}
 		}
-		$result .= ">$link_text</a>";
+
+		#
+		# Unhashify HTML blocks
+		#
+		foreach ($grafs as $key => $graf) {
+			# Modify elements of @grafs in-place...
+			if (isset($this->html_blocks[$graf])) {
+				$block = $this->html_blocks[$graf];
+				$graf = $block;
+//				if (preg_match('{
+//					\A
+//					(							# $1 = <div> tag
+//					  <div  \s+
+//					  [^>]*
+//					  \b
+//					  markdown\s*=\s*  ([\'"])	#	$2 = attr quote char
+//					  1
+//					  \2
+//					  [^>]*
+//					  >
+//					)
+//					(							# $3 = contents
+//					.*
+//					)
+//					(</div>)					# $4 = closing tag
+//					\z
+//					}xs', $block, $matches))
+//				{
+//					list(, $div_open, , $div_content, $div_close) = $matches;
+//
+//					# We can't call Markdown(), because that resets the hash;
+//					# that initialization code should be pulled into its own sub, though.
+//					$div_content = $this->hashHTMLBlocks($div_content);
+//					
+//					# Run document gamut methods on the content.
+//					foreach ($this->document_gamut as $method => $priority) {
+//						$div_content = $this->$method($div_content);
+//					}
+//
+//					$div_open = preg_replace(
+//						'{\smarkdown\s*=\s*([\'"]).+?\1}', '', $div_open);
+//
+//					$graf = $div_open . "\n" . $div_content . "\n" . $div_close;
+//				}
+				$grafs[$key] = $graf;
+			}
+		}
+
+		return implode("\n\n", $grafs);
 	}
-	else {
-		$result = $whole_match;
+
+
+	function encodeAmpsAndAngles($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 = preg_replace('/&(?!#?[xX]?(?:[0-9a-fA-F]+|\w+);)/', 
+							 '&amp;', $text);;
+
+		# Encode naked <'s
+		$text = preg_replace('{<(?![a-z/?\$!%])}i', '&lt;', $text);
+
+		return $text;
 	}
-	return $result;
-}
-function _DoAnchors_inline_callback($matches) {
-	global $md_escape_table;
-	$whole_match	= $matches[1];
-	$link_text		= $matches[2];
-	$url			= $matches[3];
-	$title			=& $matches[6];
-
-	# We've got to encode these to avoid conflicting with italics/bold.
-	$url = str_replace(array('*', '_'),
-					   array($md_escape_table['*'], $md_escape_table['_']), 
-					   $url);
-	$result = "<a href=\"$url\"";
-	if (isset($title)) {
-		$title = str_replace('"', '&quot;', $title);
-		$title = str_replace(array('*', '_'),
-							 array($md_escape_table['*'], $md_escape_table['_']),
-							 $title);
-		$result .=  " title=\"$title\"";
+
+
+	function encodeBackslashEscapes($text) {
+	#
+	#	Parameter:  String.
+	#	Returns:    The string, with after processing the following backslash
+	#				escape sequences.
+	#
+		# Must process escaped backslashes first.
+		return str_replace(array_keys($this->backslash_escape_table),
+						   array_values($this->backslash_escape_table), $text);
 	}
-	
-	$result .= ">$link_text</a>";
 
-	return $result;
-}
 
+	function doAutoLinks($text) {
+		$text = preg_replace_callback('{<((https?|ftp|dict):[^\'">\s]+)>}', 
+			array(&$this, '_doAutoLinks_url_callback'), $text);
 
-function _DoImages($text) {
-#
-# Turn Markdown image shortcuts into <img> tags.
-#
-	global $md_nested_brackets;
+		# Email addresses: <address@domain.foo>
+		$text = preg_replace_callback('{
+			<
+			(?:mailto:)?
+			(
+				[-.\w\x80-\xFF]+
+				\@
+				[-a-z0-9\x80-\xFF]+(\.[-a-z0-9\x80-\xFF]+)*\.[a-z]+
+			)
+			>
+			}xi',
+			array(&$this, '_doAutoLinks_email_callback'), $text);
+
+		return $text;
+	}
+	function _doAutoLinks_url_callback($matches) {
+		$url = $this->encodeAmpsAndAngles($matches[1]);
+		$link = "<a href=\"$url\">$url</a>";
+		return $this->hashSpan($link);
+	}
+	function _doAutoLinks_email_callback($matches) {
+		$address = $matches[1];
+		$address = $this->unescapeSpecialChars($address);
+		$link = $this->encodeEmailAddress($address);
+		return $this->hashSpan($link);
+	}
+
+
+	function encodeEmailAddress($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.:
+	#
+	#	  <p><a href="&#109;&#x61;&#105;&#x6c;&#116;&#x6f;&#58;&#x66;o&#111;
+	#        &#x40;&#101;&#x78;&#97;&#x6d;&#112;&#x6c;&#101;&#46;&#x63;&#111;
+	#        &#x6d;">&#x66;o&#111;&#x40;&#101;&#x78;&#97;&#x6d;&#112;&#x6c;
+	#        &#101;&#46;&#x63;&#111;&#x6d;</a></p>
+	#
+	#	Based by a filter by Matthew Wickline, posted to BBEdit-Talk.
+	#   With some optimizations by Milian Wolff.
+	#
+		$addr = "mailto:" . $addr;
+		$chars = preg_split('/(?<!^)(?!$)/', $addr);
+		$seed = (int)abs(crc32($addr) / strlen($addr)); # Deterministic seed.
+		
+		foreach ($chars as $key => $char) {
+			$ord = ord($char);
+			# Ignore non-ascii chars.
+			if ($ord < 128) {
+				$r = ($seed * (1 + $key)) % 100; # Pseudo-random function.
+				# roughly 10% raw, 45% hex, 45% dec
+				# '@' *must* be encoded. I insist.
+				if ($r > 90 && $char != '@') /* do nothing */;
+				else if ($r < 45) $chars[$key] = '&#x'.dechex($ord).';';
+				else              $chars[$key] = '&#'.$ord.';';
+			}
+		}
+		
+		$addr = implode('', $chars);
+		$text = implode('', array_slice($chars, 7)); # text without `mailto:`
+		$addr = "<a href=\"$addr\">$text</a>";
 
+		return $addr;
+	}
+
+
+	function unescapeSpecialChars($text) {
 	#
-	# First, handle reference-style labeled images: ![alt text][id]
+	# Swap back in all the special characters we've hidden.
 	#
-	$text = preg_replace_callback('{
-		(				# wrap whole match in $1
-		  !\[
-			('.$md_nested_brackets.')		# alt text = $2
-		  \]
+		return str_replace(array_values($this->escape_table), 
+						   array_keys($this->escape_table), $text);
+	}
+
 
-		  [ ]?				# one optional space
-		  (?:\n[ ]*)?		# one optional newline followed by spaces
+	function tokenizeHTML($str) {
+	#
+	#   Parameter:  String containing HTML + Markdown markup.
+	#   Returns:    An array of the tokens comprising the input
+	#               string. Each token is either a tag or a run of text 
+	#               between tags. Each element of the array is a
+	#               two-element array; the first is either 'tag' or 'text';
+	#               the second is the actual value.
+	#   Note:       Markdown code spans are taken into account: no tag token is 
+	#               generated within a code span.
+	#
+		$tokens = array();
 
-		  \[
-			(.*?)		# id = $3
-		  \]
+		while ($str != "") {
+			#
+			# Each loop iteration seach for either the next tag or the next 
+			# openning code span marker. If a code span marker is found, the 
+			# code span is extracted in entierty and will result in an extra
+			# text token.
+			#
+			$parts = preg_split('{
+				(
+					(?<![`\\\\])
+					`+						# code span marker
+				|
+					<!--    .*?     -->		# comment
+				|
+					<\?.*?\?> | <%.*?%>		# processing instruction
+				|
+					<[/!$]?[-a-zA-Z0-9:]+	# regular tags
+					(?:
+						\s
+						(?>[^"\'>]+|"[^"]*"|\'[^\']*\')*
+					)?
+					>
+				)
+				}xs', $str, 2, PREG_SPLIT_DELIM_CAPTURE);
+			
+			# Create token from text preceding tag.
+			if ($parts[0] != "") {
+				$tokens[] = array('text', $parts[0]);
+			}
+			
+			# Check if we reach the end.
+			if (count($parts) < 3) {
+				break;
+			}
+			
+			# Create token from tag or code span.
+			if ($parts[1]{0} == "`") {
+				$tokens[] = array('text', $parts[1]);
+				$str = $parts[2];
+				
+				# Skip the whole code span, pass as text token.
+				if (preg_match('/^(.*(?<!`\\\\)'.$parts[1].'(?!`))(.*)$/sm', 
+					$str, $matches))
+				{
+					$tokens[] = array('text', $matches[1]);
+					$str = $matches[2];
+				}
+			} else {
+				$tokens[] = array('tag', $parts[1]);
+				$str = $parts[2];
+			}
+		}
+		
+		return $tokens;
+	}
 
-		)
-		}xs', 
-		'_DoImages_reference_callback', $text);
 
+	function outdent($text) {
+	#
+	# Remove one level of line-leading tabs or spaces
 	#
-	# Next, handle inline images:  ![alt text](url "optional title")
-	# Don't forget: encode * and _
+		return preg_replace("/^(\\t|[ ]{1,$this->tab_width})/m", "", $text);
+	}
 
-	$text = preg_replace_callback('{
-		(				# wrap whole match in $1
-		  !\[
-			('.$md_nested_brackets.')		# alt text = $2
-		  \]
-		  \(			# literal paren
-			[ \t]*
-			<?(\S+?)>?	# src url = $3
-			[ \t]*
-			(			# $4
-			  ([\'"])	# quote char = $5
-			  (.*?)		# title = $6
-			  \5		# matching quote
-			  [ \t]*
-			)?			# title is optional
-		  \)
-		)
-		}xs',
-		'_DoImages_inline_callback', $text);
 
-	return $text;
-}
-function _DoImages_reference_callback($matches) {
-	global $md_urls, $md_titles, $md_empty_element_suffix, $md_escape_table;
-	$whole_match = $matches[1];
-	$alt_text    = $matches[2];
-	$link_id     = strtolower($matches[3]);
-
-	if ($link_id == "") {
-		$link_id = strtolower($alt_text); # for shortcut links like ![this][].
-	}
-
-	$alt_text = str_replace('"', '&quot;', $alt_text);
-	if (isset($md_urls[$link_id])) {
-		$url = $md_urls[$link_id];
-		# We've got to encode these to avoid conflicting with italics/bold.
-		$url = str_replace(array('*', '_'),
-						   array($md_escape_table['*'], $md_escape_table['_']),
-						   $url);
-		$result = "<img src=\"$url\" alt=\"$alt_text\"";
-		if (isset($md_titles[$link_id])) {
-			$title = $md_titles[$link_id];
-			$title = str_replace(array('*', '_'),
-								 array($md_escape_table['*'], 
-									   $md_escape_table['_']), $title);
-			$result .=  " title=\"$title\"";
+	# String length function for detab. `_initDetab` will create a function to 
+	# hanlde UTF-8 if the default function does not exist.
+	var $utf8_strlen = 'mb_strlen';
+	
+	function detab($text) {
+	#
+	# Replace tabs with the appropriate amount of space.
+	#
+		# For each line we separate the line in blocks delemited by
+		# tab characters. Then we reconstruct every line by adding the 
+		# appropriate number of space between each blocks.
+		
+		$strlen = $this->utf8_strlen; # best strlen function for UTF-8.
+		$lines = explode("\n", $text);
+		$text = "";
+		
+		foreach ($lines as $line) {
+			# Split in blocks.
+			$blocks = explode("\t", $line);
+			# Add each blocks to the line.
+			$line = $blocks[0];
+			unset($blocks[0]); # Do not add first block twice.
+			foreach ($blocks as $block) {
+				# Calculate amount of space, insert spaces, insert block.
+				$amount = $this->tab_width - 
+					$strlen($line, 'UTF-8') % $this->tab_width;
+				$line .= str_repeat(" ", $amount) . $block;
+			}
+			$text .= "$line\n";
 		}
-		$result .= $md_empty_element_suffix;
+		return $text;
 	}
-	else {
-		# If there's no such link ID, leave intact:
-		$result = $whole_match;
+	function _initDetab() {
+	#
+	# Check for the availability of the function in the `utf8_strlen` property
+	# (probably `mb_strlen`). If the function is not available, create a 
+	# function that will loosely count the number of UTF-8 characters with a
+	# regular expression.
+	#
+		if (function_exists($this->utf8_strlen)) return;
+		$this->utf8_strlen = 'Markdown_UTF8_strlen';
+		
+		if (function_exists($this->utf8_strlen)) return;
+		function Markdown_UTF8_strlen($text) {
+			return preg_match_all('/[\x00-\xBF]|[\xC0-\xFF][\x80-\xBF]*/', 
+				$text, $m);
+		}
 	}
 
-	return $result;
-}
-function _DoImages_inline_callback($matches) {
-	global $md_empty_element_suffix, $md_escape_table;
-	$whole_match	= $matches[1];
-	$alt_text		= $matches[2];
-	$url			= $matches[3];
-	$title			= '';
-	if (isset($matches[6])) {
-		$title		= $matches[6];
-	}
-
-	$alt_text = str_replace('"', '&quot;', $alt_text);
-	$title    = str_replace('"', '&quot;', $title);
-	# We've got to encode these to avoid conflicting with italics/bold.
-	$url = str_replace(array('*', '_'),
-					   array($md_escape_table['*'], $md_escape_table['_']),
-					   $url);
-	$result = "<img src=\"$url\" alt=\"$alt_text\"";
-	if (isset($title)) {
-		$title = str_replace(array('*', '_'),
-							 array($md_escape_table['*'], $md_escape_table['_']),
-							 $title);
-		$result .=  " title=\"$title\""; # $title already quoted
-	}
-	$result .= $md_empty_element_suffix;
-
-	return $result;
-}
 
+	function unhash($text) {
+	#
+	# Swap back in all the tags hashed by _HashHTMLBlocks.
+	#
+		return str_replace(array_keys($this->html_hashes), 
+						   array_values($this->html_hashes), $text);
+	}
 
-function _DoHeaders($text) {
-	# Setext-style headers:
-	#	  Header 1
-	#	  ========
-	#  
-	#	  Header 2
-	#	  --------
-	#
-	$text = preg_replace(
-		array('{ (^.+?) (?:[ ]+\{\#([-_:a-zA-Z0-9]+)\})? [ \t]*\n=+[ \t]*\n+ }emx',
-			  '{ (^.+?) (?:[ ]+\{\#([-_:a-zA-Z0-9]+)\})? [ \t]*\n-+[ \t]*\n+ }emx'),
-		array("_HashBlock('<h1'. ('\\2'? ' id=\"'._UnslashQuotes('\\2').'\"':'').
-				'>'._RunSpanGamut(_UnslashQuotes('\\1')).'</h1>'
-			  ) . '\n\n'",
-			  "_HashBlock('<h2'. ('\\2'? ' id=\"'._UnslashQuotes('\\2').'\"':'').
-				'>'._RunSpanGamut(_UnslashQuotes('\\1')).'</h2>'
-			  ) . '\n\n'"),
-		$text);
-
-	# atx-style headers:
-	#	# Header 1
-	#	## Header 2
-	#	## Header 2 with closing hashes ##
-	#	...
-	#	###### Header 6
-	#
-	$text = preg_replace('{
-			^(\#{1,6})	# $1 = string of #\'s
-			[ \t]*
-			(.+?)		# $2 = Header text
-			[ \t]*
-			\#*			# optional closing #\'s (not counted)
-			(?:[ ]+\{\#([-_:a-zA-Z0-9]+)\}[ ]*)? # id attribute
-			\n+
-		}xme',
-		"_HashBlock(
-			'<h'.strlen('\\1'). ('\\3'? ' id=\"'._UnslashQuotes('\\3').'\"':'').'>'.
-			_RunSpanGamut(_UnslashQuotes('\\2')).
-			'</h'.strlen('\\1').'>'
-		) . '\n\n'",
-		$text);
-
-	return $text;
 }
 
 
-function _DoTables($text) {
 #
-# Form HTML tables.
+# Markdown Extra Parser Class
 #
-	global $md_tab_width;
-	$less_than_tab = $md_tab_width - 1;
+
+class MarkdownExtra_Parser extends Markdown_Parser {
+
+	# Prefix for footnote ids.
+	var $fn_id_prefix = "";
+	
+	# Optional title attribute for footnote links and backlinks.
+	var $fn_link_title = MARKDOWN_FN_LINK_TITLE;
+	var $fn_backlink_title = MARKDOWN_FN_BACKLINK_TITLE;
+	
+	# Optional class attribute for footnote links and backlinks.
+	var $fn_link_class = MARKDOWN_FN_LINK_CLASS;
+	var $fn_backlink_class = MARKDOWN_FN_BACKLINK_CLASS;
+
+
+	function MarkdownExtra_Parser() {
+	#
+	# Constructor function. Initialize the parser object.
 	#
-	# Find tables with leading pipe.
+		# Add extra escapable characters before parent constructor 
+		# initialize the table.
+		$this->escape_chars .= ':|';
+		
+		# Insert extra document, block, and span transformations. 
+		# Parent constructor will do the sorting.
+		$this->document_gamut += array(
+			"stripFootnotes"     => 15,
+			"stripAbbreviations" => 25,
+			"appendFootnotes"    => 50,
+			);
+		$this->block_gamut += array(
+			"doTables"           => 15,
+			"doDefLists"         => 45,
+			);
+		$this->span_gamut += array(
+			"doFootnotes"        =>  4,
+			"doAbbreviations"    =>  5,
+			);
+		
+		parent::Markdown_Parser();
+	}
+	
+	
+	# Extra hashes used during extra transformations.
+	var $footnotes = array();
+	var $footnotes_ordered = array();
+	var $abbr_desciptions = array();
+	var $abbr_matches = array();
+	var $html_cleans = array();
+	
+	
+	function transform($text) {
 	#
-	#	| Header 1 | Header 2
-	#	| -------- | --------
-	#	| Cell 1   | Cell 2
-	#	| Cell 3   | Cell 4
+	# Added clear to the new $html_hashes, reordered `hashHTMLBlocks` before 
+	# blank line stripping and added extra parameter to `runBlockGamut`.
 	#
-	$text = preg_replace_callback('
-		{
-			^							# Start of a line
-			[ ]{0,'.$less_than_tab.'}	# Allowed whitespace.
-			[|]							# Optional leading pipe (present)
-			(.+) \n						# $1: Header row (at least one pipe)
+		# 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):
+		$this->footnotes = array();
+		$this->footnotes_ordered = array();
+		$this->abbr_desciptions = array();
+		$this->abbr_matches = array();
+		$this->html_cleans = array();
+
+		return parent::transform($text);
+	}
+	
+	
+	### HTML Block Parser ###
+	
+	# Tags that are always treated as block tags:
+	var $block_tags = 'p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|address|form|fieldset|iframe|hr|legend';
+	
+	# Tags treated as block tags only if the opening tag is alone on it's line:
+	var $context_block_tags = 'script|noscript|math|ins|del';
+	
+	# Tags where markdown="1" default to span mode:
+	var $contain_span_tags = 'p|h[1-6]|li|dd|dt|td|th|legend|address';
+	
+	# Tags which must not have their contents modified, no matter where 
+	# they appear:
+	var $clean_tags = 'script|math';
+	
+	# Tags that do not need to be closed.
+	var $auto_close_tags = 'hr|img';
+	
+
+	function hashHTMLBlocks($text) {
+	#
+	# Hashify HTML Blocks and "clean tags".
+	#
+	# 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.
+	#
+	# This works by calling _HashHTMLBlocks_InMarkdown, which then calls
+	# _HashHTMLBlocks_InHTML when it encounter block tags. When the markdown="1" 
+	# attribute is found whitin a tag, _HashHTMLBlocks_InHTML calls back
+	#  _HashHTMLBlocks_InMarkdown to handle the Markdown syntax within the tag.
+	# These two functions are calling each other. It's recursive!
+	#
+		#
+		# Call the HTML-in-Markdown hasher.
+		#
+		list($text, ) = $this->_hashHTMLBlocks_inMarkdown($text);
+		
+		return $text;
+	}
+	function _hashHTMLBlocks_inMarkdown($text, $indent = 0, 
+										$enclosing_tag = '', $span = false)
+	{
+	#
+	# Parse markdown text, calling _HashHTMLBlocks_InHTML for block tags.
+	#
+	# *   $indent is the number of space to be ignored when checking for code 
+	#     blocks. This is important because if we don't take the indent into 
+	#     account, something like this (which looks right) won't work as expected:
+	#
+	#     <div>
+	#         <div markdown="1">
+	#         Hello World.  <-- Is this a Markdown code block or text?
+	#         </div>  <-- Is this a Markdown code block or a real tag?
+	#     <div>
+	#
+	#     If you don't like this, just don't indent the tag on which
+	#     you apply the markdown="1" attribute.
+	#
+	# *   If $enclosing_tag is not empty, stops at the first unmatched closing 
+	#     tag with that name. Nested tags supported.
+	#
+	# *   If $span is true, text inside must treated as span. So any double 
+	#     newline will be replaced by a single newline so that it does not create 
+	#     paragraphs.
+	#
+	# Returns an array of that form: ( processed text , remaining text )
+	#
+		if ($text === '') return array('', '');
+
+		# Regex to check for the presense of newlines around a block tag.
+		$newline_match_before = '/(?:^\n?|\n\n)*$/';
+		$newline_match_after = 
+			'{
+				^						# Start of text following the tag.
+				(?:[ ]*<!--.*?-->)?		# Optional comment.
+				[ ]*\n					# Must be followed by newline.
+			}xs';
+		
+		# Regex to match any tag.
+		$block_tag_match =
+			'{
+				(					# $2: Capture hole tag.
+					</?					# Any opening or closing tag.
+						(?:				# Tag name.
+							'.$this->block_tags.'			|
+							'.$this->context_block_tags.'	|
+							'.$this->clean_tags.'        	|
+							(?!\s)'.$enclosing_tag.'
+						)
+						\s*				# Whitespace.
+						(?:
+							".*?"		|	# Double quotes (can contain `>`)
+							\'.*?\'   	|	# Single quotes (can contain `>`)
+							.+?				# Anything but quotes and `>`.
+						)*?
+					>					# End of tag.
+				|
+					<!--    .*?     -->	# HTML Comment
+				|
+					<\?.*?\?> | <%.*?%>	# Processing instruction
+				|
+					<!\[CDATA\[.*?\]\]>	# CData Block
+				)
+			}xs';
+
+		
+		$depth = 0;		# Current depth inside the tag tree.
+		$parsed = "";	# Parsed text that will be returned.
+
+		#
+		# Loop through every tag until we find the closing tag of the parent
+		# or loop until reaching the end of text if no parent tag specified.
+		#
+		do {
+			#
+			# Split the text using the first $tag_match pattern found.
+			# Text before  pattern will be first in the array, text after
+			# pattern will be at the end, and between will be any catches made 
+			# by the pattern.
+			#
+			$parts = preg_split($block_tag_match, $text, 2, 
+								PREG_SPLIT_DELIM_CAPTURE);
 			
-			[ ]{0,'.$less_than_tab.'}	# Allowed whitespace.
-			[|] ([ ]*[-:]+[-| :]*) \n	# $2: Header underline
+			# If in Markdown span mode, add a empty-string span-level hash 
+			# after each newline to prevent triggering any block element.
+			if ($span) {
+				$newline = $this->hashSpan("") . "\n";
+				$parts[0] = str_replace("\n", $newline, $parts[0]);
+			}
 			
-			(							# $3: Cells
-				(?:
-					[ ]*				# Allowed whitespace.
-					[|] .* \n			# Row content.
-				)*
-			)
-			(?=\n|\Z)					# Stop at final double newline.
-		}xm',
-		'_DoTable_LeadingPipe_callback', $text);
-	
+			$parsed .= $parts[0]; # Text before current tag.
+			
+			# If end of $text has been reached. Stop loop.
+			if (count($parts) < 3) {
+				$text = "";
+				break;
+			}
+			
+			$tag  = $parts[1]; # Tag to handle.
+			$text = $parts[2]; # Remaining text after current tag.
+			
+			#
+			# Check for: Tag inside code block or span
+			#
+			if (# Find current paragraph
+				preg_match('/(?>^\n?|\n\n)((?>.\n?)+?)$/', $parsed, $matches) &&
+				(
+				# Then match in it either a code block...
+				preg_match('/^ {'.($indent+4).'}.*(?>\n {'.($indent+4).'}.*)*'.
+							'(?!\n)$/', $matches[1], $x) ||
+				# ...or unbalenced code span markers. (the regex matches balenced)
+				!preg_match('/^(?>[^`]+|(`+)(?>[^`]+|(?!\1[^`])`)*?\1(?!`))*$/s',
+							 $matches[1])
+				))
+			{
+				# Tag is in code block or span and may not be a tag at all. So we
+				# simply skip the first char (should be a `<`).
+				$parsed .= $tag{0};
+				$text = substr($tag, 1) . $text; # Put back $tag minus first char.
+			}
+			#
+			# Check for: Opening Block level tag or
+			#            Opening Content Block tag (like ins and del) 
+			#               used as a block tag (tag is alone on it's line).
+			#
+			else if (preg_match("{^<(?:$this->block_tags)\b}", $tag) ||
+				(	preg_match("{^<(?:$this->context_block_tags)\b}", $tag) &&
+					preg_match($newline_match_before, $parsed) &&
+					preg_match($newline_match_after, $text)	)
+				)
+			{
+				# Need to parse tag and following text using the HTML parser.
+				list($block_text, $text) = 
+					$this->_hashHTMLBlocks_inHTML($tag . $text, "hashBlock", true);
+				
+				# Make sure it stays outside of any paragraph by adding newlines.
+				$parsed .= "\n\n$block_text\n\n";
+			}
+			#
+			# Check for: Clean tag (like script, math)
+			#            HTML Comments, processing instructions.
+			#
+			else if (preg_match("{^<(?:$this->clean_tags)\b}", $tag) ||
+				$tag{1} == '!' || $tag{1} == '?')
+			{
+				# Need to parse tag and following text using the HTML parser.
+				# (don't check for markdown attribute)
+				list($block_text, $text) = 
+					$this->_hashHTMLBlocks_inHTML($tag . $text, "hashClean", false);
+				
+				$parsed .= $block_text;
+			}
+			#
+			# Check for: Tag with same name as enclosing tag.
+			#
+			else if ($enclosing_tag !== '' &&
+				# Same name as enclosing tag.
+				preg_match("{^</?(?:$enclosing_tag)\b}", $tag))
+			{
+				#
+				# Increase/decrease nested tag count.
+				#
+				if ($tag{1} == '/')						$depth--;
+				else if ($tag{strlen($tag)-2} != '/')	$depth++;
+
+				if ($depth < 0) {
+					#
+					# Going out of parent element. Clean up and break so we
+					# return to the calling function.
+					#
+					$text = $tag . $text;
+					break;
+				}
+				
+				$parsed .= $tag;
+			}
+			else {
+				$parsed .= $tag;
+			}
+		} while ($depth >= 0);
+		
+		return array($parsed, $text);
+	}
+	function _hashHTMLBlocks_inHTML($text, $hash_method, $md_attr) {
 	#
-	# Find tables without leading pipe.
+	# Parse HTML, calling _HashHTMLBlocks_InMarkdown for block tags.
 	#
-	#	Header 1 | Header 2
-	#	-------- | --------
-	#	Cell 1   | Cell 2
-	#	Cell 3   | Cell 4
+	# *   Calls $hash_method to convert any blocks.
+	# *   Stops when the first opening tag closes.
+	# *   $md_attr indicate if the use of the `markdown="1"` attribute is allowed.
+	#     (it is not inside clean tags)
 	#
-	$text = preg_replace_callback('
-		{
-			^							# Start of a line
-			[ ]{0,'.$less_than_tab.'}	# Allowed whitespace.
-			(\S.*[|].*) \n				# $1: Header row (at least one pipe)
+	# Returns an array of that form: ( processed text , remaining text )
+	#
+		if ($text === '') return array('', '');
+		
+		# Regex to match `markdown` attribute inside of a tag.
+		$markdown_attr_match = '
+			{
+				\s*			# Eat whitespace before the `markdown` attribute
+				markdown
+				\s*=\s*
+				(["\'])		# $1: quote delimiter		
+				(.*?)		# $2: attribute value
+				\1			# matching delimiter	
+			}xs';
+		
+		# Regex to match any tag.
+		$tag_match = '{
+				(					# $2: Capture hole tag.
+					</?					# Any opening or closing tag.
+						[\w:$]+			# Tag name.
+						\s*				# Whitespace.
+						(?:
+							".*?"		|	# Double quotes (can contain `>`)
+							\'.*?\'   	|	# Single quotes (can contain `>`)
+							.+?				# Anything but quotes and `>`.
+						)*?
+					>					# End of tag.
+				|
+					<!--    .*?     -->	# HTML Comment
+				|
+					<\?.*?\?> | <%.*?%>	# Processing instruction
+				|
+					<!\[CDATA\[.*?\]\]>	# CData Block
+				)
+			}xs';
+		
+		$original_text = $text;		# Save original text in case of faliure.
+		
+		$depth		= 0;	# Current depth inside the tag tree.
+		$block_text	= "";	# Temporary text holder for current text.
+		$parsed		= "";	# Parsed text that will be returned.
+
+		#
+		# Get the name of the starting tag.
+		#
+		if (preg_match("/^<([\w:$]*)\b/", $text, $matches))
+			$base_tag_name = $matches[1];
+
+		#
+		# Loop through every tag until we find the corresponding closing tag.
+		#
+		do {
+			#
+			# Split the text using the first $tag_match pattern found.
+			# Text before  pattern will be first in the array, text after
+			# pattern will be at the end, and between will be any catches made 
+			# by the pattern.
+			#
+			$parts = preg_split($tag_match, $text, 2, PREG_SPLIT_DELIM_CAPTURE);
+			
+			if (count($parts) < 3) {
+				#
+				# End of $text reached with unbalenced tag(s).
+				# In that case, we return original text unchanged and pass the
+				# first character as filtered to prevent an infinite loop in the 
+				# parent function.
+				#
+				return array($original_text{0}, substr($original_text, 1));
+			}
 			
-			[ ]{0,'.$less_than_tab.'}	# Allowed whitespace.
-			([-:]+[ ]*[|][-| :]*) \n	# $2: Header underline
+			$block_text .= $parts[0]; # Text before current tag.
+			$tag         = $parts[1]; # Tag to handle.
+			$text        = $parts[2]; # Remaining text after current tag.
 			
-			(							# $3: Cells
-				(?:
-					.* [|] .* \n		# Row content
-				)*
-			)
-			(?=\n|\Z)					# Stop at final double newline.
-		}xm',
-		'_DoTable_callback', $text);
+			#
+			# Check for: Auto-close tag (like <hr/>)
+			#			 Comments and Processing Instructions.
+			#
+			if (preg_match("{^</?(?:$this->auto_close_tags)\b}", $tag) ||
+				$tag{1} == '!' || $tag{1} == '?')
+			{
+				# Just add the tag to the block as if it was text.
+				$block_text .= $tag;
+			}
+			else {
+				#
+				# Increase/decrease nested tag count. Only do so if
+				# the tag's name match base tag's.
+				#
+				if (preg_match("{^</?$base_tag_name\b}", $tag)) {
+					if ($tag{1} == '/')						$depth--;
+					else if ($tag{strlen($tag)-2} != '/')	$depth++;
+				}
+				
+				#
+				# Check for `markdown="1"` attribute and handle it.
+				#
+				if ($md_attr && 
+					preg_match($markdown_attr_match, $tag, $attr_matches) &&
+					preg_match('/^1|block|span$/', $attr_matches[2]))
+				{
+					# Remove `markdown` attribute from opening tag.
+					$tag = preg_replace($markdown_attr_match, '', $tag);
+					
+					# Check if text inside this tag must be parsed in span mode.
+					$this->mode = $attr_matches[2];
+					$span_mode = $this->mode == 'span' || $this->mode != 'block' &&
+						preg_match("{^<(?:$this->contain_span_tags)\b}", $tag);
+					
+					# Calculate indent before tag.
+					preg_match('/(?:^|\n)( *?)(?! ).*?$/', $block_text, $matches);
+					$indent = strlen($matches[1]);
+					
+					# End preceding block with this tag.
+					$block_text .= $tag;
+					$parsed .= $this->$hash_method($block_text);
+					
+					# Get enclosing tag name for the ParseMarkdown function.
+					preg_match('/^<([\w:$]*)\b/', $tag, $matches);
+					$tag_name = $matches[1];
+					
+					# Parse the content using the HTML-in-Markdown parser.
+					list ($block_text, $text)
+						= $this->_hashHTMLBlocks_inMarkdown($text, $indent, 
+														$tag_name, $span_mode);
+					
+					# Outdent markdown text.
+					if ($indent > 0) {
+						$block_text = preg_replace("/^[ ]{1,$indent}/m", "", 
+													$block_text);
+					}
+					
+					# Append tag content to parsed text.
+					if (!$span_mode)	$parsed .= "\n\n$block_text\n\n";
+					else				$parsed .= "$block_text";
+					
+					# Start over a new block.
+					$block_text = "";
+				}
+				else $block_text .= $tag;
+			}
+			
+		} while ($depth > 0);
+		
+		#
+		# Hash last block text that wasn't processed inside the loop.
+		#
+		$parsed .= $this->$hash_method($block_text);
+		
+		return array($parsed, $text);
+	}
 
-	return $text;
-}
-function _DoTable_LeadingPipe_callback($matches) {
-	$head		= $matches[1];
-	$underline	= $matches[2];
-	$content	= $matches[3];
-	
-	# Remove leading pipe for each row.
-	$content	= preg_replace('/^ *[|]/m', '', $content);
-	
-	return _DoTable_callback(array($matches[0], $head, $underline, $content));
-}
-function _DoTable_callback($matches) {
-	$head		= $matches[1];
-	$underline	= $matches[2];
-	$content	= $matches[3];
-
-	# Remove any tailing pipes for each line.
-	$head		= preg_replace('/[|] *$/m', '', $head);
-	$underline	= preg_replace('/[|] *$/m', '', $underline);
-	$content	= preg_replace('/[|] *$/m', '', $content);
-	
-	# Reading alignement from header underline.
-	$separators	= preg_split('/ *[|] */', $underline);
-	foreach ($separators as $n => $s) {
-		if (preg_match('/^ *-+: *$/', $s))		$attr[$n] = ' align="right"';
-		else if (preg_match('/^ *:-+: *$/', $s))$attr[$n] = ' align="center"';
-		else if (preg_match('/^ *:-+ *$/', $s))	$attr[$n] = ' align="left"';
-		else									$attr[$n] = '';
+
+	function hashClean($text) {
+	#
+	# Called whenever a tag must be hashed when a function insert a "clean" tag
+	# in $text, it pass through this function and is automaticaly escaped, 
+	# blocking invalid nested overlap.
+	#
+		# Swap back any tag hash found in $text so we do not have to `unhash`
+		# multiple times at the end.
+		$text = $this->unhash($text);
+		
+		# Then hash the tag.
+		$key = md5($text);
+		$this->html_cleans[$key] = $text;
+		$this->html_hashes[$key] = $text;
+		return $key; # String that will replace the clean tag.
+	}
+
+
+	function doHeaders($text) {
+	#
+	# Redefined to add id attribute support.
+	#
+		# Setext-style headers:
+		#	  Header 1  {#header1}
+		#	  ========
+		#  
+		#	  Header 2  {#header2}
+		#	  --------
+		#
+		$text = preg_replace_callback(
+			'{ (^.+?) (?:[ ]+\{\#([-_:a-zA-Z0-9]+)\})? [ \t]*\n=+[ \t]*\n+ }mx',
+			array(&$this, '_doHeaders_callback_setext_h1'), $text);
+		$text = preg_replace_callback(
+			'{ (^.+?) (?:[ ]+\{\#([-_:a-zA-Z0-9]+)\})? [ \t]*\n-+[ \t]*\n+ }mx',
+			array(&$this, '_doHeaders_callback_setext_h2'), $text);
+
+		# atx-style headers:
+		#	# Header 1        {#header1}
+		#	## Header 2       {#header2}
+		#	## Header 2 with closing hashes ##  {#header3}
+		#	...
+		#	###### Header 6   {#header2}
+		#
+		$text = preg_replace_callback('{
+				^(\#{1,6})	# $1 = string of #\'s
+				[ \t]*
+				(.+?)		# $2 = Header text
+				[ \t]*
+				\#*			# optional closing #\'s (not counted)
+				(?:[ ]+\{\#([-_:a-zA-Z0-9]+)\})? # id attribute
+				[ \t]*
+				\n+
+			}xm',
+			array(&$this, '_doHeaders_callback_atx'), $text);
+
+		return $text;
+	}
+	function _doHeaders_attr($attr) {
+		if (empty($attr))  return "";
+		return " id=\"$attr\"";
+	}
+	function _doHeaders_callback_setext_h1($matches) {
+		$attr  = $this->_doHeaders_attr($id =& $matches[2]);
+		$block = "<h1$attr>".$this->runSpanGamut($matches[1])."</h1>";
+		return "\n" . $this->hashBlock($block) . "\n\n";
+	}
+	function _doHeaders_callback_setext_h2($matches) {
+		$attr  = $this->_doHeaders_attr($id =& $matches[2]);
+		$block = "<h2$attr>".$this->runSpanGamut($matches[1])."</h2>";
+		return "\n" . $this->hashBlock($block) . "\n\n";
+	}
+	function _doHeaders_callback_atx($matches) {
+		$level = strlen($matches[1]);
+		$attr  = $this->_doHeaders_attr($id =& $matches[3]);
+		$block = "<h$level$attr>".$this->runSpanGamut($matches[2])."</h$level>";
+		return "\n" . $this->hashBlock($block) . "\n\n";
+	}
+
+
+	function doTables($text) {
+	#
+	# Form HTML tables.
+	#
+		$less_than_tab = $this->tab_width - 1;
+		#
+		# Find tables with leading pipe.
+		#
+		#	| Header 1 | Header 2
+		#	| -------- | --------
+		#	| Cell 1   | Cell 2
+		#	| Cell 3   | Cell 4
+		#
+		$text = preg_replace_callback('
+			{
+				^							# Start of a line
+				[ ]{0,'.$less_than_tab.'}	# Allowed whitespace.
+				[|]							# Optional leading pipe (present)
+				(.+) \n						# $1: Header row (at least one pipe)
+				
+				[ ]{0,'.$less_than_tab.'}	# Allowed whitespace.
+				[|] ([ ]*[-:]+[-| :]*) \n	# $2: Header underline
+				
+				(							# $3: Cells
+					(?:
+						[ ]*				# Allowed whitespace.
+						[|] .* \n			# Row content.
+					)*
+				)
+				(?=\n|\Z)					# Stop at final double newline.
+			}xm',
+			array(&$this, '_doTable_leadingPipe_callback'), $text);
+		
+		#
+		# Find tables without leading pipe.
+		#
+		#	Header 1 | Header 2
+		#	-------- | --------
+		#	Cell 1   | Cell 2
+		#	Cell 3   | Cell 4
+		#
+		$text = preg_replace_callback('
+			{
+				^							# Start of a line
+				[ ]{0,'.$less_than_tab.'}	# Allowed whitespace.
+				(\S.*[|].*) \n				# $1: Header row (at least one pipe)
+				
+				[ ]{0,'.$less_than_tab.'}	# Allowed whitespace.
+				([-:]+[ ]*[|][-| :]*) \n	# $2: Header underline
+				
+				(							# $3: Cells
+					(?:
+						.* [|] .* \n		# Row content
+					)*
+				)
+				(?=\n|\Z)					# Stop at final double newline.
+			}xm',
+			array(&$this, '_DoTable_callback'), $text);
+
+		return $text;
+	}
+	function _doTable_leadingPipe_callback($matches) {
+		$head		= $matches[1];
+		$underline	= $matches[2];
+		$content	= $matches[3];
+		
+		# Remove leading pipe for each row.
+		$content	= preg_replace('/^ *[|]/m', '', $content);
+		
+		return $this->_doTable_callback(array($matches[0], $head, $underline, $content));
 	}
-	
-	# Creating code spans before splitting the row is an easy way to 
-	# handle a code span containg pipes.
-	$head	= _DoCodeSpans($head);
-	$headers	= preg_split('/ *[|] */', $head);
-	$col_count	= count($headers);
-	
-	# Write column headers.
-	$text = "<table>\n";
-	$text .= "<thead>\n";
-	$text .= "<tr>\n";
-	foreach ($headers as $n => $header)
-		$text .= "  <th$attr[$n]>"._RunSpanGamut(trim($header))."</th>\n";
-	$text .= "</tr>\n";
-	$text .= "</thead>\n";
-	
-	# Split content by row.
-	$rows = explode("\n", trim($content, "\n"));
-	
-	$text .= "<tbody>\n";
-	foreach ($rows as $row) {
+	function _doTable_callback($matches) {
+		$head		= $matches[1];
+		$underline	= $matches[2];
+		$content	= $matches[3];
+
+		# Remove any tailing pipes for each line.
+		$head		= preg_replace('/[|] *$/m', '', $head);
+		$underline	= preg_replace('/[|] *$/m', '', $underline);
+		$content	= preg_replace('/[|] *$/m', '', $content);
+		
+		# Reading alignement from header underline.
+		$separators	= preg_split('/ *[|] */', $underline);
+		foreach ($separators as $n => $s) {
+			if (preg_match('/^ *-+: *$/', $s))		$attr[$n] = ' align="right"';
+			else if (preg_match('/^ *:-+: *$/', $s))$attr[$n] = ' align="center"';
+			else if (preg_match('/^ *:-+ *$/', $s))	$attr[$n] = ' align="left"';
+			else									$attr[$n] = '';
+		}
+		
 		# Creating code spans before splitting the row is an easy way to 
 		# handle a code span containg pipes.
-		$row = _DoCodeSpans($row);
-		
-		# Split row by cell.
-		$row_cells = preg_split('/ *[|] */', $row, $col_count);
-		$row_cells = array_pad($row_cells, $col_count, '');
+		$head	= $this->doCodeSpans($head);
+		$headers	= preg_split('/ *[|] */', $head);
+		$col_count	= count($headers);
 		
+		# Write column headers.
+		$text = "<table>\n";
+		$text .= "<thead>\n";
 		$text .= "<tr>\n";
-		foreach ($row_cells as $n => $cell)
-			$text .= "  <td$attr[$n]>"._RunSpanGamut(trim($cell))."</td>\n";
+		foreach ($headers as $n => $header)
+			$text .= "  <th$attr[$n]>".$this->runSpanGamut(trim($header))."</th>\n";
 		$text .= "</tr>\n";
+		$text .= "</thead>\n";
+		
+		# Split content by row.
+		$rows = explode("\n", trim($content, "\n"));
+		
+		$text .= "<tbody>\n";
+		foreach ($rows as $row) {
+			# Creating code spans before splitting the row is an easy way to 
+			# handle a code span containg pipes.
+			$row = $this->doCodeSpans($row);
+			
+			# Split row by cell.
+			$row_cells = preg_split('/ *[|] */', $row, $col_count);
+			$row_cells = array_pad($row_cells, $col_count, '');
+			
+			$text .= "<tr>\n";
+			foreach ($row_cells as $n => $cell)
+				$text .= "  <td$attr[$n]>".$this->runSpanGamut(trim($cell))."</td>\n";
+			$text .= "</tr>\n";
+		}
+		$text .= "</tbody>\n";
+		$text .= "</table>";
+		
+		return $this->hashBlock($text) . "\n";
 	}
-	$text .= "</tbody>\n";
-	$text .= "</table>";
-	
-	return _HashBlock($text) . "\n";
-}
 
+	
+	function doDefLists($text) {
+	#
+	# Form HTML definition lists.
+	#
+		$less_than_tab = $this->tab_width - 1;
 
-function _DoLists($text) {
-#
-# Form HTML ordered (numbered) and unordered (bulleted) lists.
-#
-	global $md_tab_width, $md_list_level;
-	$less_than_tab = $md_tab_width - 1;
-
-	# Re-usable patterns to match list item bullets and number markers:
-	$marker_ul  = '[*+-]';
-	$marker_ol  = '\d+[.]';
-	$marker_any = "(?:$marker_ul|$marker_ol)";
-
-	$markers = array($marker_ul, $marker_ol);
-
-	foreach ($markers as $marker) {
-		# Re-usable pattern to match any entirel ul or ol list:
+		# Re-usable pattern to match any entire dl list:
 		$whole_list = '
 			(								# $1 = whole list
 			  (								# $2
 				[ ]{0,'.$less_than_tab.'}
-				('.$marker.')				# $3 = first list item marker
-				[ \t]+
+				((?>.*\S.*\n)+)				# $3 = defined term
+				\n?
+				[ ]{0,'.$less_than_tab.'}:[ ]+ # colon starting definition
 			  )
 			  (?s:.+?)
 			  (								# $4
@@ -1216,669 +2252,393 @@ function _DoLists($text) {
 				|
 				  \n{2,}
 				  (?=\S)
-				  (?!						# Negative lookahead for another list item marker
-					[ \t]*
-					'.$marker.'[ \t]+
+				  (?!						# Negative lookahead for another term
+					[ ]{0,'.$less_than_tab.'}
+					(?: \S.*\n )+?			# defined term
+					\n?
+					[ ]{0,'.$less_than_tab.'}:[ ]+ # colon starting definition
+				  )
+				  (?!						# Negative lookahead for another definition
+					[ ]{0,'.$less_than_tab.'}:[ ]+ # colon starting definition
 				  )
 			  )
 			)
 		'; // mx
-		
-		# We use a different prefix before nested lists than top-level lists.
-		# See extended comment in _ProcessListItems().
-	
-		if ($md_list_level) {
-			$text = preg_replace_callback('{
-					^
-					'.$whole_list.'
-				}mx',
-				'_DoLists_callback', $text);
-		}
-		else {
-			$text = preg_replace_callback('{
-					(?:(?<=\n\n)|\A\n?)
-					'.$whole_list.'
-				}mx',
-				'_DoLists_callback', $text);
-		}
-	}
-
-	return $text;
-}
-function _DoLists_callback($matches) {
-	# Re-usable patterns to match list item bullets and number markers:
-	$marker_ul  = '[*+-]';
-	$marker_ol  = '\d+[.]';
-	$marker_any = "(?:$marker_ul|$marker_ol)";
-	
-	$list = $matches[1];
-	$list_type = preg_match("/$marker_ul/", $matches[3]) ? "ul" : "ol";
-	
-	$marker_any = ( $list_type == "ul" ? $marker_ul : $marker_ol );
-	
-	# Turn double returns into triple returns, so that we can make a
-	# paragraph for the last item in a list, if necessary:
-	$list = preg_replace("/\n{2,}/", "\n\n\n", $list);
-	$result = _ProcessListItems($list, $marker_any);
-	$result = "<$list_type>\n" . $result . "</$list_type>";
-	return "\n" . _HashBlock($result) . "\n\n";
-}
 
+		$text = preg_replace_callback('{
+				(?:(?<=\n\n)|\A\n?)
+				'.$whole_list.'
+			}mx',
+			array(&$this, '_doDefLists_callback'), $text);
 
-function _ProcessListItems($list_str, $marker_any) {
-#
-#	Process the contents of a single ordered or unordered list, splitting it
-#	into individual list items.
-#
-	global $md_list_level;
-	
-	# The $md_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.".
-	
-	$md_list_level++;
-
-	# trim trailing blank lines:
-	$list_str = preg_replace("/\n{2,}\\z/", "\n", $list_str);
-
-	$list_str = preg_replace_callback('{
-		(\n)?							# leading line = $1
-		(^[ \t]*)						# leading whitespace = $2
-		('.$marker_any.') [ \t]+		# list marker = $3
-		((?s:.+?)						# list item text   = $4
-		(\n{1,2}))
-		(?= \n* (\z | \2 ('.$marker_any.') [ \t]+))
-		}xm',
-		'_ProcessListItems_callback', $list_str);
-
-	$md_list_level--;
-	return $list_str;
-}
-function _ProcessListItems_callback($matches) {
-	$item = $matches[4];
-	$leading_line =& $matches[1];
-	$leading_space =& $matches[2];
-
-	if ($leading_line || preg_match('/\n{2,}/', $item)) {
-		$item = _RunBlockGamut(_Outdent($item));
+		return $text;
 	}
-	else {
-		# Recursion for sub-lists:
-		$item = _DoLists(_Outdent($item));
-		$item = preg_replace('/\n+$/', '', $item);
-		$item = _RunSpanGamut($item);
+	function _doDefLists_callback($matches) {
+		# Re-usable patterns to match list item bullets and number markers:
+		$list = $matches[1];
+		
+		# Turn double returns into triple returns, so that we can make a
+		# paragraph for the last item in a list, if necessary:
+		$result = trim($this->processDefListItems($list));
+		$result = "<dl>\n" . $result . "\n</dl>";
+		return $this->hashBlock($result) . "\n\n";
 	}
 
-	return "<li>" . $item . "</li>\n";
-}
-
-
-function _DoDefLists($text) {
-#
-# Form HTML definition lists.
-#
-	global $md_tab_width;
-	$less_than_tab = $md_tab_width - 1;
-
-	# Re-usable patterns to match list item bullets and number markers:
-
-	# Re-usable pattern to match any entire dl list:
-	$whole_list = '
-		(								# $1 = whole list
-		  (								# $2
-			[ ]{0,'.$less_than_tab.'}
-			((?>.*\S.*\n)+)				# $3 = defined term
-			\n?
-			[ ]{0,'.$less_than_tab.'}:[ ]+ # colon starting definition
-		  )
-		  (?s:.+?)
-		  (								# $4
-			  \z
-			|
-			  \n{2,}
-			  (?=\S)
-			  (?!						# Negative lookahead for another term
-				[ ]{0,'.$less_than_tab.'}
-				(?: \S.*\n )+?			# defined term
-				\n?
-				[ ]{0,'.$less_than_tab.'}:[ ]+ # colon starting definition
-			  )
-			  (?!						# Negative lookahead for another definition
-				[ ]{0,'.$less_than_tab.'}:[ ]+ # colon starting definition
-			  )
-		  )
-		)
-	'; // mx
-
-	$text = preg_replace_callback('{
-			(?:(?<=\n\n)|\A\n?)
-			'.$whole_list.'
-		}mx',
-		'_DoDefLists_callback', $text);
-
-	return $text;
-}
-function _DoDefLists_callback($matches) {
-	# Re-usable patterns to match list item bullets and number markers:
-	$list = $matches[1];
-	
-	# Turn double returns into triple returns, so that we can make a
-	# paragraph for the last item in a list, if necessary:
-	$result = trim(_ProcessDefListItems($list));
-	$result = "<dl>\n" . $result . "\n</dl>";
-	return _HashBlock($result) . "\n\n";
-}
-
 
-function _ProcessDefListItems($list_str) {
-#
-#	Process the contents of a single ordered or unordered list, splitting it
-#	into individual list items.
-#
-	global $md_tab_width;
-	$less_than_tab = $md_tab_width - 1;
-	
-	# trim trailing blank lines:
-	$list_str = preg_replace("/\n{2,}\\z/", "\n", $list_str);
-
-	# Process definition terms.
-	$list_str = preg_replace_callback('{
-		(?:\n\n+|\A\n?)					# leading line
-		(								# definition terms = $1
-			[ ]{0,'.$less_than_tab.'}	# leading whitespace
-			(?![:][ ]|[ ])				# negative lookahead for a definition 
-										#   mark (colon) or more whitespace.
-			(?: \S.* \n)+?				# actual term (not whitespace).	
-		)			
-		(?=\n?[ ]{0,3}:[ ])				# lookahead for following line feed 
-										#   with a definition mark.
-		}xm',
-		'_ProcessDefListItems_callback_dt', $list_str);
-
-	# Process actual definitions.
-	$list_str = preg_replace_callback('{
-		\n(\n+)?						# leading line = $1
-		[ ]{0,'.$less_than_tab.'}		# whitespace before colon
-		[:][ ]+							# definition mark (colon)
-		((?s:.+?))						# definition text = $2
-		(?= \n+ 						# stop at next definition mark,
-			(?:							# next term or end of text
-				[ ]{0,'.$less_than_tab.'} [:][ ]	|
-				<dt> | \z
-			)						
-		)					
-		}xm',
-		'_ProcessDefListItems_callback_dd', $list_str);
-
-	return $list_str;
-}
-function _ProcessDefListItems_callback_dt($matches) {
-	$terms = explode("\n", trim($matches[1]));
-	$text = '';
-	foreach ($terms as $term) {
-		$term = _RunSpanGamut(trim($term));
-		$text .= "\n<dt>" . $term . "</dt>";
-	}
-	return $text . "\n";
-}
-function _ProcessDefListItems_callback_dd($matches) {
-	$leading_line	= $matches[1];
-	$def			= $matches[2];
-
-	if ($leading_line || preg_match('/\n{2,}/', $def)) {
-		$def = _RunBlockGamut(_Outdent($def . "\n\n"));
-		$def = "\n". $def ."\n";
+	function processDefListItems($list_str) {
+	#
+	#	Process the contents of a single definition list, splitting it
+	#	into individual term and definition list items.
+	#
+		$less_than_tab = $this->tab_width - 1;
+		
+		# trim trailing blank lines:
+		$list_str = preg_replace("/\n{2,}\\z/", "\n", $list_str);
+
+		# Process definition terms.
+		$list_str = preg_replace_callback('{
+			(?:\n\n+|\A\n?)					# leading line
+			(								# definition terms = $1
+				[ ]{0,'.$less_than_tab.'}	# leading whitespace
+				(?![:][ ]|[ ])				# negative lookahead for a definition 
+											#   mark (colon) or more whitespace.
+				(?: \S.* \n)+?				# actual term (not whitespace).	
+			)			
+			(?=\n?[ ]{0,3}:[ ])				# lookahead for following line feed 
+											#   with a definition mark.
+			}xm',
+			array(&$this, '_processDefListItems_callback_dt'), $list_str);
+
+		# Process actual definitions.
+		$list_str = preg_replace_callback('{
+			\n(\n+)?						# leading line = $1
+			[ ]{0,'.$less_than_tab.'}		# whitespace before colon
+			[:][ ]+							# definition mark (colon)
+			((?s:.+?))						# definition text = $2
+			(?= \n+ 						# stop at next definition mark,
+				(?:							# next term or end of text
+					[ ]{0,'.$less_than_tab.'} [:][ ]	|
+					<dt> | \z
+				)						
+			)					
+			}xm',
+			array(&$this, '_processDefListItems_callback_dd'), $list_str);
+
+		return $list_str;
 	}
-	else {
-		$def = rtrim($def);
-		$def = _RunSpanGamut(_Outdent($def));
+	function _processDefListItems_callback_dt($matches) {
+		$terms = explode("\n", trim($matches[1]));
+		$text = '';
+		foreach ($terms as $term) {
+			$term = $this->runSpanGamut(trim($term));
+			$text .= "\n<dt>" . $term . "</dt>";
+		}
+		return $text . "\n";
 	}
+	function _processDefListItems_callback_dd($matches) {
+		$leading_line	= $matches[1];
+		$def			= $matches[2];
 
-	return "\n<dd>" . $def . "</dd>\n";
-}
-
-
-function _DoCodeBlocks($text) {
-#
-#	Process Markdown `<pre><code>` blocks.
-#
-	global $md_tab_width;
-	$text = preg_replace_callback('{
-			(?:\n\n|\A)
-			(	            # $1 = the code block -- one or more lines, starting with a space/tab
-			  (?:
-				(?:[ ]{'.$md_tab_width.'} | \t)  # Lines must start with a tab or a tab-width of spaces
-				.*\n+
-			  )+
-			)
-			((?=^[ ]{0,'.$md_tab_width.'}\S)|\Z)	# Lookahead for non-space at line-start, or end of doc
-		}xm',
-		'_DoCodeBlocks_callback', $text);
-
-	return $text;
-}
-function _DoCodeBlocks_callback($matches) {
-	$codeblock = $matches[1];
-
-	$codeblock = _EncodeCode(_Outdent($codeblock));
-//	$codeblock = _Detab($codeblock);
-	# trim leading newlines and trailing whitespace
-	$codeblock = preg_replace(array('/\A\n+/', '/\s+\z/'), '', $codeblock);
-
-	$result = "<pre><code>" . $codeblock . "\n</code></pre>";
-
-	return "\n\n" . _HashBlock($result) . "\n\n";
-}
-
-
-function _DoCodeSpans($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 = preg_replace_callback('@
-			(?<!\\\)	# Character before opening ` can\'t be a backslash
-			(`+)		# $1 = Opening run of `
-			(.+?)		# $2 = The code block
-			(?<!`)
-			\1			# Matching closer
-			(?!`)
-		@xs',
-		'_DoCodeSpans_callback', $text);
-
-	return $text;
-}
-function _DoCodeSpans_callback($matches) {
-	$c = $matches[2];
-	$c = preg_replace('/^[ \t]*/', '', $c); # leading whitespace
-	$c = preg_replace('/[ \t]*$/', '', $c); # trailing whitespace
-	$c = _EncodeCode($c);
-	return "<code>$c</code>";
-}
-
+		if ($leading_line || preg_match('/\n{2,}/', $def)) {
+			$def = $this->runBlockGamut($this->outdent($def . "\n\n"));
+			$def = "\n". $def ."\n";
+		}
+		else {
+			$def = rtrim($def);
+			$def = $this->runSpanGamut($this->outdent($def));
+		}
 
-function _EncodeCode($_) {
-#
-# Encode/escape certain characters inside Markdown code runs.
-# The point is that in code, these characters are literals,
-# and lose their special Markdown meanings.
-#
-	global $md_escape_table;
+		return "\n<dd>" . $def . "</dd>\n";
+	}
 
-	# Encode all ampersands; HTML entities are not
-	# entities within a Markdown code span.
-	$_ = str_replace('&', '&amp;', $_);
 
-	# Do the angle bracket song and dance:
-	$_ = str_replace(array('<',    '>'), 
-					 array('&lt;', '&gt;'), $_);
+	function doItalicsAndBold($text) {
+	#
+	# Redefined to change emphasis by underscore behaviour so that it does not 
+	# work in the middle of a word.
+	#
+		# <strong> must go first:
+		$text = preg_replace_callback(array(
+			'{
+				(						# $1: Marker
+					(?<![a-zA-Z0-9])	# Not preceded by alphanum
+					(?<!__)				#	or by two marker chars.
+					__
+				)
+				(?=\S) 					# Not followed by whitespace 
+				(?!__)					#   or two others marker chars.
+				(						# $2: Content
+					(?:
+						[^_]+?			# Anthing not em markers.
+					|
+										# Balence any regular _ emphasis inside.
+						(?<![a-zA-Z0-9]) _ (?=\S) (.+?) 
+						(?<=\S) _ (?![a-zA-Z0-9])
+					|
+						___+
+					)+?
+				)
+				(?<=\S) __				# End mark not preceded by whitespace.
+				(?![a-zA-Z0-9])			# Not followed by alphanum
+				(?!__)					#   or two others marker chars.
+			}sx',
+			'{
+				( (?<!\*\*) \*\* )		# $1: Marker (not preceded by two *)
+				(?=\S) 					# Not followed by whitespace 
+				(?!\1)					#   or two others marker chars.
+				(						# $2: Content
+					(?:
+						[^*]+?			# Anthing not em markers.
+					|
+										# Balence any regular * emphasis inside.
+						\* (?=\S) (.+?) (?<=\S) \*
+					)+?
+				)
+				(?<=\S) \*\*			# End mark not preceded by whitespace.
+			}sx',
+			),
+			array(&$this, '_doItalicAndBold_strong_callback'), $text);
+		# Then <em>:
+		$text = preg_replace_callback(array(
+			'{ ( (?<![a-zA-Z0-9])(?<!_)_ ) (?=\S) (?! \1) (.+?) (?<=\S) \1(?![a-zA-Z0-9]) }sx',
+			'{ ( (?<!\*)\* ) (?=\S) (?! \1) (.+?) (?<=\S) \1 }sx',
+			),
+			array(&$this, '_doItalicAndBold_em_callback'), $text);
+
+		return $text;
+	}
 
-	# Now, escape characters that are magic in Markdown:
-	$_ = str_replace(array_keys($md_escape_table), 
-					 array_values($md_escape_table), $_);
 
-	return $_;
-}
+	function formParagraphs($text) {
+	#
+	#	Params:
+	#		$text - string to process with html <p> tags
+	#
+		# Strip leading and trailing lines:
+		$text = preg_replace(array('/\A\n+/', '/\n+\z/'), '', $text);
+		
+		$grafs = preg_split('/\n{2,}/', $text, -1, PREG_SPLIT_NO_EMPTY);
 
+		#
+		# Wrap <p> tags and unhashify HTML blocks
+		#
+		foreach ($grafs as $key => $value) {
+			$value = trim($this->runSpanGamut($value));
+			
+			# Check if this should be enclosed in a paragraph.
+			# Clean tag hashes & block tag hashes are left alone.
+			$clean_key = $value;
+			$block_key = substr($value, 0, 32);
+			
+			$is_p = (!isset($this->html_blocks[$block_key]) && 
+					 !isset($this->html_cleans[$clean_key]));
+			
+			if ($is_p) {
+				$value = "<p>$value</p>";
+			}
+			$grafs[$key] = $value;
+		}
+		
+		# Join grafs in one text, then unhash HTML tags. 
+		$text = implode("\n\n", $grafs);
+		
+		# Finish by removing any tag hashes still present in $text.
+		$text = $this->unhash($text);
+		
+		return $text;
+	}
+	
+	
+	### Footnotes
+	
+	function stripFootnotes($text) {
+	#
+	# Strips link definitions from text, stores the URLs and titles in
+	# hash references.
+	#
+		$less_than_tab = $this->tab_width - 1;
 
-function _DoItalicsAndBold($text) {
-	# <strong> must go first:
-	$text = preg_replace(array(
-		'{
-			( (?<!\w) __ )			# $1: Marker (not preceded by alphanum)
-			(?=\S) 					# Not followed by whitespace 
-			(?!__)					#   or two others marker chars.
-			(						# $2: Content
-				(?>
-					[^_]+?			# Anthing not em markers.
-				|
-									# Balence any regular _ emphasis inside.
-					(?<![a-zA-Z0-9])_ (?=\S) (?! _) (.+?) 
-					(?<=\S) _ (?![a-zA-Z0-9])
-				)+?
-			)
-			(?<=\S) __				# End mark not preceded by whitespace.
-			(?!\w)					# Not followed by alphanum.
-		}sx',
-		'{
-			( (?<!\*\*) \*\* )		# $1: Marker (not preceded by two *)
-			(?=\S) 					# Not followed by whitespace 
-			(?!\1)					#   or two others marker chars.
-			(						# $2: Content
-				(?>
-					[^*]+?			# Anthing not em markers.
+		# Link defs are in the form: [^id]: url "optional title"
+		$text = preg_replace_callback('{
+			^[ ]{0,'.$less_than_tab.'}\[\^(.+?)\][ ]?:	# note_id = $1
+			  [ \t]*
+			  \n?					# maybe *one* newline
+			(						# text = $2 (no blank lines allowed)
+				(?:					
+					.+				# actual text
 				|
-									# Balence any regular * emphasis inside.
-					\* (?=\S) (?! \*) (.+?) (?<=\S) \*
-				)+?
-			)
-			(?<=\S) \*\*			# End mark not preceded by whitespace.
-		}sx',
-		),
-		'<strong>\2</strong>', $text);
-	# Then <em>:
-	$text = preg_replace(array(
-		'{ ( (?<!\w) _ ) (?=\S) (?! _)  (.+?) (?<=\S) _ (?!\w) }sx',
-		'{ ( (?<!\*)\* ) (?=\S) (?! \*) (.+?) (?<=\S) \* }sx',
-		),
-		'<em>\2</em>', $text);
-
-	return $text;
-}
-
-
-function _DoBlockQuotes($text) {
-	$text = preg_replace_callback('/
-		  (								# 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
-			)+
-		  )
-		/xm',
-		'_DoBlockQuotes_callback', $text);
-
-	return $text;
-}
-function _DoBlockQuotes_callback($matches) {
-	$bq = $matches[1];
-	# trim one level of quoting - trim whitespace-only lines
-	$bq = preg_replace(array('/^[ \t]*>[ \t]?/m', '/^[ \t]+$/m'), '', $bq);
-	$bq = _RunBlockGamut($bq);		# recurse
-
-	$bq = preg_replace('/^/m', "  ", $bq);
-	# These leading spaces screw with <pre> content, so we need to fix that:
-	$bq = preg_replace_callback('{(\s*<pre>.+?</pre>)}sx', 
-								'_DoBlockQuotes_callback2', $bq);
-
-	return _HashBlock("<blockquote>\n$bq\n</blockquote>") . "\n\n";
-}
-function _DoBlockQuotes_callback2($matches) {
-	$pre = $matches[1];
-	$pre = preg_replace('/^  /m', '', $pre);
-	return $pre;
-}
+					\n				# newlines but 
+					(?!\[\^.+?\]:\s)# negative lookahead for footnote marker.
+					(?!\n+[ ]{0,3}\S)# ensure line is not blank and followed 
+									# by non-indented content
+				)*
+			)		
+			}xm',
+			array(&$this, '_stripFootnotes_callback'),
+			$text);
+		return $text;
+	}
+	function _stripFootnotes_callback($matches) {
+		$note_id = $matches[1];
+		$this->footnotes[$note_id] = $this->outdent($matches[2]);
+		return ''; # String that will replace the block
+	}
 
 
-function _FormParagraphs($text) {
-#
-#	Params:
-#		$text - string to process with html <p> tags
-#
-	global $md_html_blocks, $md_html_hashes;
+	function doFootnotes($text) {
+	#
+	# Replace footnote references in $text [^id] with a special text-token 
+	# which will be can be
+	#
+		$text = preg_replace('{\[\^(.+?)\]}', "a\0fn:\\1\0z", $text);
+		return $text;
+	}
 
-	# Strip leading and trailing lines:
-	$text = preg_replace(array('/\A\n+/', '/\n+\z/'), '', $text);
 	
-	$grafs = preg_split('/\n{2,}/', $text, -1, PREG_SPLIT_NO_EMPTY);
-
+	function appendFootnotes($text) {
 	#
-	# Wrap <p> tags and unhashify HTML blocks
+	# Append footnote list to text.
 	#
-	foreach ($grafs as $key => $value) {
-		$value = trim(_RunSpanGamut($value));
-		
-		# Check if this should be enclosed in a paragraph.
-		# Text equaling to a clean tag hash are not enclosed.
-		# Text starting with a block tag hash are not either.
-		$clean_key = $value;
-		$block_key = substr($value, 0, 32);
-		
-		$is_p = (!isset($md_html_blocks[$block_key]) && 
-				 !isset($md_html_hashes[$clean_key]));
+		$text = preg_replace_callback('{a\0fn:(.*?)\0z}', 
+			array(&$this, '_appendFootnotes_callback'), $text);
+	
+		if (!empty($this->footnotes_ordered)) {
+			$text .= "\n\n";
+			$text .= "<div class=\"footnotes\">\n";
+			$text .= "<hr". MARKDOWN_EMPTY_ELEMENT_SUFFIX ."\n";
+			$text .= "<ol>\n\n";
+			
+			$attr = " rev=\"footnote\"";
+			if ($this->fn_backlink_class != "") {
+				$class = $this->fn_backlink_class;
+				$class = $this->encodeAmpsAndAngles($class);
+				$class = str_replace('"', '&quot;', $class);
+				$attr .= " class=\"$class\"";
+			}
+			if ($this->fn_backlink_title != "") {
+				$title = $this->fn_backlink_title;
+				$title = $this->encodeAmpsAndAngles($title);
+				$title = str_replace('"', '&quot;', $title);
+				$attr .= " title=\"$title\"";
+			}
+			$num = 0;
+			
+			foreach ($this->footnotes_ordered as $note_id => $footnote) {
+				$footnote .= "\n"; # Need to append newline before parsing.
+				$footnote = $this->runBlockGamut("$footnote\n");
+				
+				$attr2 = str_replace("%%", ++$num, $attr);
+				
+				# Add backlink to last paragraph; create new paragraph if needed.
+				$backlink = "<a href=\"#fnref:$note_id\"$attr2>&#8617;</a>";
+				if (preg_match('{</p>$}', $footnote)) {
+					$footnote = substr($footnote, 0, -4) . "&#160;$backlink</p>";
+				} else {
+					$footnote .= "\n\n<p>$backlink</p>";
+				}
+				
+				$text .= "<li id=\"fn:$note_id\">\n";
+				$text .= $footnote . "\n";
+				$text .= "</li>\n\n";
+			}
+			
+			$text .= "</ol>\n";
+			$text .= "</div>";
+			
+			$text = preg_replace('{a\{fn:(.*?)\}z}', '[^\\1]', $text);
+		}
+		return $text;
+	}
+	function _appendFootnotes_callback($matches) {
+		$node_id = $this->fn_id_prefix . $matches[1];
 		
-		if ($is_p) {
-			$value = "<p>$value</p>";
+		# Create footnote marker only if it has a corresponding footnote *and*
+		# the footnote hasn't been used by another marker.
+		if (isset($this->footnotes[$node_id])) {
+			# Transfert footnote content to the ordered list.
+			$this->footnotes_ordered[$node_id] = $this->footnotes[$node_id];
+			unset($this->footnotes[$node_id]);
+			
+			$num = count($this->footnotes_ordered);
+			$attr = " rel=\"footnote\"";
+			if ($this->fn_link_class != "") {
+				$class = $this->fn_link_class;
+				$class = $this->encodeAmpsAndAngles($class);
+				$class = str_replace('"', '&quot;', $class);
+				$attr .= " class=\"$class\"";
+			}
+			if ($this->fn_link_title != "") {
+				$title = $this->fn_link_title;
+				$title = $this->encodeAmpsAndAngles($title);
+				$title = str_replace('"', '&quot;', $title);
+				$attr .= " title=\"$title\"";
+			}
+			$attr = str_replace("%%", $num, $attr);
+			
+			return
+				"<sup id=\"fnref:$node_id\">".
+				"<a href=\"#fn:$node_id\"$attr>$num</a>".
+				"</sup>";
 		}
-		$grafs[$key] = $value;
+		
+		return "[^".$matches[1]."]";
 	}
+		
 	
-	# Join grafs in one text, then unhash HTML tags. 
-	$text = implode("\n\n", $grafs);
-	
-	# Finish by removing any tag hashes still present in $text.
-	$text = _UnhashTags($text);
+	### Abbreviations ###
 	
-	return $text;
-}
-
-
-function _EncodeAmpsAndAngles($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 = preg_replace('/&(?!#?[xX]?(?:[0-9a-fA-F]+|\w+);)/', 
-						 '&amp;', $text);;
-
-	# Encode naked <'s
-	$text = preg_replace('{<(?![a-z/?\$!])}i', '&lt;', $text);
-
-	return $text;
-}
-
-
-function _EncodeBackslashEscapes($text) {
-#
-#	Parameter:  String.
-#	Returns:    The string, with after processing the following backslash
-#				escape sequences.
-#
-	global $md_escape_table, $md_backslash_escape_table;
-	# Must process escaped backslashes first.
-	return str_replace(array_keys($md_backslash_escape_table),
-					   array_values($md_backslash_escape_table), $text);
-}
-
-
-function _DoAutoLinks($text) {
-	$text = preg_replace("!<((https?|ftp):[^'\">\\s]+)>!", 
-						 '<a href="\1">\1</a>', $text);
-
-	# Email addresses: <address@domain.foo>
-	$text = preg_replace('{
-		<
-        (?:mailto:)?
-		(
-			[-.\w]+
-			\@
-			[-a-z0-9]+(\.[-a-z0-9]+)*\.[a-z]+
-		)
-		>
-		}exi',
-		"_EncodeEmailAddress(_UnescapeSpecialChars(_UnslashQuotes('\\1')))",
-		$text);
-
-	return $text;
-}
-
-
-function _EncodeEmailAddress($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 by a filter by Matthew Wickline, posted to the BBEdit-Talk
-#	mailing list: <http://tinyurl.com/yu7ue>
-#
-	$addr = "mailto:" . $addr;
-	$length = strlen($addr);
-
-	# leave ':' alone (to spot mailto: later)
-	$addr = preg_replace_callback('/([^\:])/', 
-								  '_EncodeEmailAddress_callback', $addr);
-
-	$addr = "<a href=\"$addr\">$addr</a>";
-	# strip the mailto: from the visible part
-	$addr = preg_replace('/">.+?:/', '">', $addr);
-
-	return $addr;
-}
-function _EncodeEmailAddress_callback($matches) {
-	$char = $matches[1];
-	$r = rand(0, 100);
-	# roughly 10% raw, 45% hex, 45% dec
-	# '@' *must* be encoded. I insist.
-	if ($r > 90 && $char != '@') return $char;
-	if ($r < 45) return '&#x'.dechex(ord($char)).';';
-	return '&#'.ord($char).';';
-}
-
-
-function _UnescapeSpecialChars($text) {
-#
-# Swap back in all the special characters we've hidden.
-#
-	global $md_escape_table;
-	return str_replace(array_values($md_escape_table), 
-					   array_keys($md_escape_table), $text);
-}
-
-
-function _UnhashTags($text) {
-#
-# Swap back in all the tags hashed by _HashHTMLBlocks.
-#
-	global $md_html_hashes;
-	return str_replace(array_keys($md_html_hashes), 
-					   array_values($md_html_hashes), $text);
-}
-
-
-# _TokenizeHTML is shared between PHP Markdown and PHP SmartyPants.
-# We only define it if it is not already defined.
-if (!function_exists('_TokenizeHTML')) :
-function _TokenizeHTML($str) {
-#
-#   Parameter:  String containing HTML markup.
-#   Returns:    An array of the tokens comprising the input
-#               string. Each token is either a tag (possibly with nested,
-#               tags contained therein, such as <a href="<MTFoo>">, or a
-#               run of text between tags. Each element of the array is a
-#               two-element array; the first is either 'tag' or 'text';
-#               the second is the actual value.
-#
-#
-#   Regular expression derived from the _tokenize() subroutine in 
-#   Brad Choate's MTRegex plugin.
-#   <http://www.bradchoate.com/past/mtregex.php>
-#
-	$index = 0;
-	$tokens = array();
-
-	$match = '(?s:<!(?:--.*?--\s*)+>)|'.	# comment
-			 '(?s:<\?.*?\?>)|'.				# processing instruction
-			 								# regular tags
-			 '(?:<[/!$]?[-a-zA-Z0-9:]+\b(?>[^"\'>]+|"[^"]*"|\'[^\']*\')*>)'; 
-
-	$parts = preg_split("{($match)}", $str, -1, PREG_SPLIT_DELIM_CAPTURE);
-
-	foreach ($parts as $part) {
-		if (++$index % 2 && $part != '') 
-			$tokens[] = array('text', $part);
-		else
-			$tokens[] = array('tag', $part);
+	function stripAbbreviations($text) {
+	#
+	# Strips abbreviations from text, stores the URLs and titles in
+	# hash references.
+	#
+		$less_than_tab = $this->tab_width - 1;
+
+		# Link defs are in the form: [id]*: url "optional title"
+		$text = preg_replace_callback('{
+			^[ ]{0,'.$less_than_tab.'}\*\[(.+?)\][ ]?:	# abbr_id = $1
+			(.*)					# text = $2 (no blank lines allowed)	
+			}xm',
+			array(&$this, '_stripAbbreviations_callback'),
+			$text);
+		return $text;
 	}
-
-	return $tokens;
-}
-endif;
-
-
-function _Outdent($text) {
-#
-# Remove one level of line-leading tabs or spaces
-#
-	global $md_tab_width;
-	return preg_replace("/^(\\t|[ ]{1,$md_tab_width})/m", "", $text);
-}
-
-
-function _Detab($text) {
-#
-# Replace tabs with the appropriate amount of space.
-#
-	global $md_tab_width;
-
-	# For each line we separate the line in blocks delemited by
-	# tab characters. Then we reconstruct every line by adding the 
-	# appropriate number of space between each blocks.
+	function _stripAbbreviations_callback($matches) {
+		$abbr_word = $matches[1];
+		$abbr_desc = $matches[2];
+		$this->abbr_matches[] = preg_quote($abbr_word);
+		$this->abbr_desciptions[$abbr_word] = trim($abbr_desc);
+		return ''; # String that will replace the block
+	}
+	
 	
-	$lines = explode("\n", $text);
-	$text = "";
+	function doAbbreviations($text) {
+	#
+	# Replace footnote references in $text [^id] with a link to the footnote.
+	#
+		if ($this->abbr_matches) {
+			$regex = '{(?<!\w)(?:'. implode('|', $this->abbr_matches) .')(?!\w)}';
 	
-	foreach ($lines as $line) {
-		# Split in blocks.
-		$blocks = explode("\t", $line);
-		# Add each blocks to the line.
-		$line = $blocks[0];
-		unset($blocks[0]); # Do not add first block twice.
-		foreach ($blocks as $block) {
-			# Calculate amount of space, insert spaces, insert block.
-			$amount = $md_tab_width - strlen($line) % $md_tab_width;
-			$line .= str_repeat(" ", $amount) . $block;
+			$text = preg_replace_callback($regex, 
+				array(&$this, '_doAbbreviations_callback'), $text);
+		}
+		return $text;
+	}
+	function _doAbbreviations_callback($matches) {
+		$abbr = $matches[0];
+		if (isset($this->abbr_desciptions[$abbr])) {
+			$desc = $this->abbr_desciptions[$abbr];
+			if (empty($desc)) {
+				return $this->hashSpan("<abbr>$abbr</abbr>");
+			} else {
+				$desc = $this->escapeSpecialCharsWithinTagAttributes($desc);
+				return $this->hashSpan("<abbr title=\"$desc\">$abbr</abbr>");
+			}
+		} else {
+			return $matches[0];
 		}
-		$text .= "$line\n";
 	}
-	return $text;
-}
-
 
-function _UnslashQuotes($text) {
-#
-#	This function is useful to remove automaticaly slashed double quotes
-#	when using preg_replace and evaluating an expression.
-#	Parameter:  String.
-#	Returns:    The string with any slash-double-quote (\") sequence replaced
-#				by a single double quote.
-#
-	return str_replace('\"', '"', $text);
 }
 
 
@@ -1890,9 +2650,10 @@ PHP Markdown Extra
 Description
 -----------
 
-This is a PHP translation of the original Markdown formatter written in
-Perl by John Gruber. This special version of PHP Markdown also include 
-syntax additions by myself.
+This is a PHP port of the original Markdown formatter written in Perl 
+by John Gruber. This special "Extra" version of PHP Markdown features 
+further enhancements to the syntax for making additional constructs 
+such as tables and definition list.
 
 Markdown is a text-to-HTML filter; it translates an easy-to-read /
 easy-to-write structured text format into HTML. Markdown's text format
@@ -1921,42 +2682,31 @@ expected; (3) the output Markdown actually produced.
 
 
 Version History
---------------- 
+---------------
 
 See Readme file for details.
 
-Extra 1.0.1 - 9 December 2005
-
-Extra 1.0 - 5 September 2005
-
-Extra 1.0b4 - 1 August 2005
+Extra 1.1.2 (7 Feb 2007)
 
-Extra 1.0b3 - 29 July 2005
+Extra 1.1.1 (28 Dec 2006)
 
-Extra 1.0b2 - 26 July 2005
-
-Extra 1.0b1 - 25 July 2005
-
-
-Author & Contributors
----------------------
+Extra 1.1 (1 Dec 2006)
 
-Original Markdown in Perl by John Gruber  
-<http://daringfireball.net/>
+Extra 1.0.1 (9 Dec 2005)
 
-PHP port and extras by Michel Fortin  
-<http://www.michelf.com/>
+Extra 1.0 (5 Sep 2005)
 
 
 Copyright and License
 ---------------------
 
-Copyright (c) 2004-2005 Michel Fortin  
+PHP Markdown & Extra
+Copyright (c) 2004-2007 Michel Fortin  
 <http://www.michelf.com/>  
 All rights reserved.
 
 Based on Markdown  
-Copyright (c) 2003-2004 John Gruber   
+Copyright (c) 2003-2006 John Gruber   
 <http://daringfireball.net/>   
 All rights reserved.
 
-- 
2.39.5