ducktyping.php

<?php
// Duck typing

class Car
{
    public function run() {
		return 'car is running';
	}
}

class Truck
{
	public function run() {
		return 'my truck is moving';
	}
}

class VehicleRunner
{
	// doesn't indicate specific type
	// be flexible in terms of what gets passed in
	public function run($vehicle) {
		return $vehicle->run();
	}
}

$vehicle = new VehicleRunner();
$vehicle->run( new Car() );
$vehicle->run( new Truck() );
?>