Embed Gists in (X)HTML without using document.write()

embed_gists.php

<?php

/**
 * Replaces Gist javascript instances with their actual content,
 * avoiding the use of document.write().
 *
 * @param string $source (X)HTML source
 *
 * @return string (X)HTML with embedded Gists
 */
function embed_gists($source)
{
    $gists_regex = '/<script[^>]+src="(http:\/\/gist.github.com\/[^"]+)"[^>]*><\/script>/i';

    preg_match_all($gists_regex, $source, $gists);

    for ($i = 0, $n = count($gists[0]); $i < $n; $i++) {

        $embed = file_get_contents($gists[1][$i]);

        if ($embed != false) {

            // remove document.writes
            $embed = preg_replace('/document.write\(\'/i', '', $embed);
            $embed = preg_replace('/(*ANYCRLF)\'\)$/m', '', $embed);

            // remove javascript newlines
            $embed = preg_replace('%(?<!/)\\\\n%', '', $embed);

            // reverse javascript escaping
            $embed = stripslashes($embed);

            // remove line breaks
            $embed = preg_replace("/[\n\r]/", '',$embed);

            // replace the script tag
            $source = str_replace($gists[0][$i], $embed, $source);

        }

    }

    return $source;
}

?>