happy.php

happy.php

<?php

interface Text {
	public function __toString();
}

class HappyBirthday implements Text {
	
	private $restOfLine = '';
	
	public function __construct($restOfLine) {
		$this->restOfLine = $restOfLine;
	}
	
	public function __toString() {
		return 'Happy birthday '.$this->restOfLine;
	}
}

class To implements Text {
	
	private $who = null;
	
	public function __construct($who) {
		$this->who = $who;
	}
	
	public function __toString() {
		return 'to '.$this->who;
	}
}

class Dear implements Text {
	
	private $prefix = '';
	
	public function __construct($prefix) {
		$this->prefix = $prefix;
	}
	
	public function __toString() {
		return 'dear '.(string)$this->prefix;
	}
}


class Who implements Text {

	private $who = '';
	
	public function __construct($who) {
        $this->who = $who;
    }

	public function __toString() {
		return (string)$this->who;
	}
}

class Song implements Iterator {
	
	private $position = 0;
	
	private $lines = null;
	
	public function __construct(ArrayObject $lines) {
		$this->lines = $lines;
	}
	
	public function current (){
		return $this->lines[$this->position].'!'.PHP_EOL;
	}

	public function next () {
		$this->position = $this->position + 1;
	}

	public function key () {
		return $this->position;
	}

	public function valid () {
		return isset($this->lines[$this->position]);
	}

	public function rewind () {
		$this->posistion = 0;
	}
}

$lines = new Song(
	new ArrayObject(array(
		new HappyBirthday(new To(new Who('you'))),
		new HappyBirthday(new To(new Who('you'))),
		new HappyBirthday(new To(new Dear(new Who('SilverStripe')))),
		new HappyBirthday(new To(new Who('you')))
	))
);

foreach($lines as $line) {
	echo $line;
}