playing with php class object

class-object.php

<?php
// 201602211052, 201605282339
error_reporting(E_ALL); ini_set('display_errors', 1);

class Anoop {
	public function bend($elm,$attack) {
		if (!isset($this->{$elm})) {
			$this->{$elm} = new ELement($elm);
		}
		$this->{$elm}->technique($attack);
	}
}
class ELement {
	private $jurus = [];
	private $index;
	public function technique($jurus) {
		$this->jurus[] = $jurus;
		$this->index = count($this->jurus)-1;
	}
	public function attack($index = null) {
		$this->index = $index === null ? $this->index : $index;
		$jurus = $this->jurus[$this->index];
		echo " -----> ".$jurus."\n";
	}
}

echo "<pre>";

$anoop = new Anoop;
$anoop->bend('water','Shark Bite');
$anoop->water->attack();
$anoop->bend('water','Tsunami Wall');
$anoop->water->attack();

$anoop->bend('wind','Tornado Needle');
$anoop->wind->attack();

$anoop->bend('fire','Merapi Wedhus Gembel');
$anoop->fire->attack();

$anoop->water->attack(0);

/*
result:
---------------------------
-----> Shark Bite
-----> Tsunami Wall
-----> Tornado Needle
-----> Merapi Wedhus Gembel
-----> Shark Bite
---------------------------
*/