透過這個類別和方法，可以做到一些很棒的事情，例如動態地新增方法到物件。
MetaTrait.php
<?php
trait MetaTrait
{
private $methods = array();
public function addMethod($methodName, $methodCallable)
{
if (!is_callable($methodCallable)) {
throw new InvalidArgumentException('第二個參數必須是可呼叫的');
}
$this->methods[$methodName] = Closure::bind($methodCallable, $this, get_class());
}
public function __call($methodName, array $args)
{
if (isset($this->methods[$methodName])) {
return call_user_func_array($this->methods[$methodName], $args);
}
throw RunTimeException('沒有指定名稱的方法可以呼叫');
}
}
?>
test.php
<?php
require 'MetaTrait.php';
class HackThursday {
use MetaTrait;
private $dayOfWeek = 'Thursday';
}
$test = new HackThursday();
$test->addMethod('when', function () {
return $this->dayOfWeek;
});
echo $test->when();
?>
