Traversal router in a tweet

tr.php

<?php

// Compressed 138 bytes
// function m($s,$t,$r){foreach($s as$p){if(!isset($t[$p]))break;$t=$t[$p];}foreach($r as$e)if ($e[1]?:$p==$p&&is_a($t,$e[0]))return[$e,$t];}

function m($s, $t, $r) {
 foreach ($s as $p) {
  if (!isset($t[$p])) break;
  $t = $t[$p];
 }
 foreach ($r as $e)
  if ($e[1]?:$p == $p && is_a($t, $e[0]))
   return [$e, $t];
}

// Example:
//   $ php -S 127.0.0.1:8080
//   $ firefox http://localhost:8080/tr.php/users/123
//   $ firefox http://localhost:8080/tr.php/users/123/edit

class User extends ArrayObject {
 public $name;
 public function __construct($name) {
  $this->name = $name;
 }
}

$root = array(
 'users' => array(
  123 => new User('John'),
 ),
);

$routes = array(
 array('User', 'edit', 'edit_user'),
 array('User', '', 'view_user'),
);

function view_user(User $user) {
 print("User: {$user->name}");
}

function edit_user(User $user) {
 $user->name = 'John Doe';
 view_user($user);
}

$path = array_filter(explode('/', $_SERVER['PATH_INFO']));

list($route, $model) = m($path, $root, $routes);

if ($route === null) {
 http_response_code(404);
 print('Not Found');
} else {
 call_user_func($route[2], $model);
}