patch for PHP Markdown Extra 1.2.4 to use GeSHi to add syntax coloring to code block. first line of your codeblock need to be the language id line: ie: #!php (github and posterous' way)

PHP_Markdown_Extra+GeSHi.patch

--- markdown.php	2009-10-10 10:11:04.000000000 -0400
+++ markdown-geshi.php	2010-06-16 16:54:51.000000000 -0400
@@ -2,6 +2,11 @@
 #
 # Markdown Extra  -  A text-to-HTML conversion tool for web writers
 #
+# GeSHI addition by Eric Leclerc
+#  uses GeSHI 1.0.8.8. add a shebang line as the first line of your
+#  code block to trigger GeSHI parsing/highlighting, ie:
+#      #!php
+#
 # PHP Markdown & Extra
 # Copyright (c) 2004-2009 Michel Fortin  
 # <http://michelf.com/projects/php-markdown/>
@@ -15,6 +20,7 @@
 define( 'MARKDOWN_VERSION',  "1.0.1n" ); # Sat 10 Oct 2009
 define( 'MARKDOWNEXTRA_VERSION',  "1.2.4" ); # Sat 10 Oct 2009
 
+require_once realpath(dirname(__FILE__) . '/../geshi-1.0.8.8/geshi.php');
 
 #
 # Global default settings:
@@ -1121,12 +1127,20 @@
 		$codeblock = $matches[1];
 
 		$codeblock = $this->outdent($codeblock);
-		$codeblock = htmlspecialchars($codeblock, ENT_NOQUOTES);
 
 		# trim leading newlines and trailing newlines
 		$codeblock = preg_replace('/\A\n+|\n+\z/', '', $codeblock);
 
-		$codeblock = "<pre><code>$codeblock\n</code></pre>";
+		// if it start with a language tag (ie: #!php), use GeSHi to convert the code
+		if (preg_match('/^#!(\w+)/', $codeblock, $match)) {
+			$codeblock = str_replace("#!${match[1]}\n", '', $codeblock);
+			$geshi = new GeSHi($codeblock, $match[1]);
+			$codeblock = $geshi->parse_code();
+		} else {
+			$codeblock = htmlspecialchars($codeblock, ENT_NOQUOTES);
+			$codeblock = "<pre><code>$codeblock\n</code></pre>";
+		}
+
 		return "\n\n".$this->hashBlock($codeblock)."\n\n";
 	}
 
@@ -2842,6 +2856,14 @@
 
 }
 
+// If there's command line argument, markdownify the file from the first argument
+if (!empty($argv[1])) {
+	$filename = realpath($argv[1]);
+	if (file_exists($filename)) {
+		$rawtext = file_get_contents($filename);
+		echo Markdown($rawtext);
+	}
+}
 
 /*