getPath.php

<?php

function getPath($target, $path, $default=null) {
    if (!$target) return $default;
    if (!$path) return $target;

    $parts = explode('.', $path);
    while (list($idx, $key) = each($parts)) {
        if (isset($target->$key)) {
            $target = $target->$key;
            continue;
        }
        elseif (is_array($target)) {
            if ($key === '@each') {
                $acc = array();
                foreach ($target as $t) {
                    $subpath = join('.', array_slice($parts, $idx+1));
                    $acc[] = (array) getPath($t, $subpath);
                }
                return call_user_func_array('array_merge', $acc);
            }
            elseif (isset($target[$key])) {
                $target = $target[$key];
                continue;
            }
        }
        return $default;
    }
    return $target;
}