<!-- Collection of code snippets by Arne Vajhøj -->
<!-- posted to eksperten.dk, usenet and other places (2002-now) -->
<?php
function process($s, $callback, $include = false) {
    $lvl = -1;
    $buf = array();
    for($i = 0; $i < strlen($s); $i++) {
        $c = $s[$i];
        switch($c) {
            case '{':
                if($include && $lvl >= 0) $buf[$lvl] .= '{';
                $lvl++;
                $buf[$lvl] = '';
                break;
            case '}':
                $callback($buf[$lvl]);
                $lvl--;
                if($include&& $lvl >= 0) $buf[$lvl] .= '}';
                break;
            default:
                for($j = 0; $j <= $lvl; $j++) $buf[$j] .= $c;
                break;
        }
    }
}

function display($match) {
    echo $match . "\r\n";
}

process('Hello {world of {warcraft}}', 'display');
process('Hello {world of {warcraft}}', 'display', true);
process('Du drikker {cola} med Lars i en {børnehave}.', 'display');
?>