Question

simple one really, i’ve written a regular expression to find and replace tags with php constants from within a html snippet. my solution, which works, just doesn’t feel right. how can this be improved?

preg_match_all('/\{CONSTANT_(.*)\}/', $final, $result, PREG_PATTERN_ORDER);
            for ($i = 0; $i < count($result[1]); $i++) {
               $final = str_replace($result[0][$i], constant($result[1][$i]),$final);
            }

Answer 1

You can do it all in one hit with preg_replace_callback

function getConstant($matches) 
{
    return constant($matches[1]);
}
$final=preg_replace_callback(
           '/\{CONSTANT_(.*?)\}/',
           "getConstant",
           $final);

Note I’ve made the .* non greedy with .*?, this will have the effect of ensuring it doesn’t go eating a } if a longer match is possible. You could get the same effect with ([^}]*), or better yet, ([a-zA-Z0-9_]+)