Mungeable PHP objects - playing with PHP 5.4 RC1

mungeable.php

<?php
/**
 * Playing with some of PHP 5.4 RC1's features
 *
 * A trait to make an object "mungeable"; i.e. so you can "munge"
 * methods (closures/lambdas) and properties into it. 
 *
 * All methods and properties will be public.
 *
 * This is pure experimentation. Please do not attempt to derive any
 * kind of best practices from it or use it as evidence for me being
 * a terrible programmer or an otherwise terrible person.
 *
 * Tom Hudson 2011-11-12
 */

trait Mungeable {
  // Note the shiny new short array syntax!
  protected $methods    = [];
  protected $properties = [];

  /**
   * Add a method to the object
   */
  public function method($name, Closure $closure){
    // bindTo causes "$this" in the closure body to refer to the bound object
    $this->methods[$name] = $closure->bindTo($this);
    return $this;
  }

  /**
   * Add a property to the object
   */
  public function property($name, $value = null){
    $this->properties[$name] = $value;
    return $this;
  }

  public function __get($key){
    return isSet($this->properties[$key])?
      $this->properties[$key] : null;
  }

  public function __set($key, $value){
    return $this->properties[$key] = $value;
  }

  public function __call($method, $arguments){
    if (!isSet($this->methods[$method])){
      throw new \BadMethodCallException(
        "{$method} is not a valid method."
      );
    }
    return call_user_func_array(
      $this->methods[$method], $arguments
    );
  }
}

/**
 * I hate contrived examples as much as the next guy or gal, 
 * but what's a little Greeter class between friends?
 */
class Greeter {
  // Use the Mungeable trait; obviously. 
  use Mungeable;

  protected $name;

  public function __construct($name){
    $this->name = $name;
  }

  /**
   * Real methods can live alongside "munged" methods
   */
  public function hello(){
    return "Hello, {$this->name}!\n";
  }
}

// All very standard so far...
$tomGreeter = new Greeter('Tom');
echo $tomGreeter->hello(); // Hello, Tom!

// It is possible to add munged properties at run-time
$tomGreeter->property('relative', 'mother');

// We can also add munged methods that refer to said properties
$tomGreeter->method('askAboutRelative', function(){
  return "How's your {$this->relative}?\n";
});

echo $tomGreeter->askAboutRelative(); // How's your mother?