PHP Exportable Class

exportable.php

<?php
/*
 * @author Christian Mayer <http://fox21.at>
 * @link http://stackoverflow.com/q/21762276/823644
 * @link https://eval.in/163041
 * @link https://eval.in/163462
 * @link https://eval.in/163909
 * @link https://gist.github.com/TheFox/49ff6903da287c30e72f
 */

interface Exportable{
	public function __get_state();
}

function unset_with_get_state($expression){
	$before = clone $expression;
	$classVars = array_keys(get_class_vars(get_class($before)));
	foreach(array_diff($classVars, $before->__get_state()) as $var){
		unset($before->$var);
	}
	return $before;
}

function my_var_export($expression, $return = null){
	$before = $expression;
	if($before instanceof Exportable){
		$before = unset_with_get_state($expression);
	}
	return var_export($before, $return);
}

class Foo implements Exportable{
	public $name = null;
	public $foo = null;
	public $bar = null;
	
	public function __get_state(){
		// Only show 'name' and 'bar' on my_var_export().
		return array('name', 'bar');
	}
}

$a = 'hello';
my_var_export($a);
print "\n";

$b = new Foo();
$b->name = 'world';
$b->foo = 'foo is foo';
$b->bar = 'bar is bar';
my_var_export($b);
print "\n";