PHP Meta Programming PHP 5.4

MetaTrait.php

<?php
trait MetaTrait
{
    
    private $methods = array();
 
    public function addMethod($methodName, $methodCallable)
    {
        if (!is_callable($methodCallable)) {
            throw new InvalidArgumentException('Second param must be callable');
        }
        $this->methods[$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 new RunTimeException('There is no method with the given name to call');
    }
 
}

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();