Online PHP editor | refs for lf9V3

<?php interface Permissions { public function isReadable(); public function isWritable(); } class ReadOnly implements Permissions { public function isReadable() { return true; } public function isWritable() { return false; } } class WriteOnly implements Permissions { public function isReadable() { return false; } public function isWritable() { return true; } } class ReadWrite implements Permissions { public function isReadable() { return true; } public function isWritable() { return true; } } class Field { private $name; private $permissions; public function __construct($name, Permissions $permissions = null) { $this->name = (string) $name; $this->permissions = $permissions ?: new ReadOnly; } public function getName() { return $this->name; } public function isReadable() { return $this->permissions->isReadable(); } public function isWritable() { return $this->permissions->isWritable(); } } $a = new Field('a'); var_dump($a->isReadable()); var_dump($a->isWritable()); $b = new Field('b', new ReadWrite); var_dump($b->isReadable()); var_dump($b->isWritable());