[gist: ####] formatting with PHP

gistfile1.php

<?php
// Gist replacement inspired by http://github.com/guitsaru/code-feather/
    if(preg_match("/\[gist: ([0-9]+)\]/i", $out, $matches)) {
        return '<script src="http://gist.github.com/'.$matches[1].'.js"></script>';
    }

// Can also be done in one line.
    $out = preg_replace("/\[gist: ([0-9]+)\]/i", '<script src="http://gist.github.com/\\1.js"></script>', $out);
 
?>