Appion

h1. Object Oriented Programming

h2. Objects

* often models a real-world thing - person, animal, shape, car 

* collection of *attributes* and *behaviors*

* defined by a class

h2. Polymorhism

h3. PHP example

<pre>

interface IAnimal {

    function getName();

    function talk();

}

abstract class AnimalBase implements IAnimal {

    protected $name;

    public function __construct($name) {

        $this->name = $name;

    }

    public function getName() {

        return $this->name;

    }

}

class Cat extends AnimalBase {

    public function talk() {

        return 'Meowww!';

    }

}

class Dog extends AnimalBase {

    public function talk() {

        return 'Woof! Woof!';

    }

}

$animals = array(

    new Cat('Missy'),

    new Cat('Mr. Mistoffelees'),

    new Dog('Lassie')

);

foreach ($animals as $animal) {

    echo $animal->getName() . ': ' . $animal->talk();

}

</pre>

h3. Python Example

<pre>

class Animal:

    def __init__(self, name):    # Constructor of the class

        self.name = name

    def talk(self):              # Abstract method, defined by convention only

        raise NotImplementedError("Subclass must implement abstract method")

class Cat(Animal):

    def talk(self):

        return 'Meow!'

class Dog(Animal):

    def talk(self):

        return 'Woof! Woof!'

animals = [Cat('Missy'),

           Cat('Mr. Mistoffelees'),

           Dog('Lassie')]

for animal in animals:

    print animal.name + ': ' + animal.talk()

# prints the following:

#

# Missy: Meow!

# Mr. Mistoffelees: Meow!

# Lassie: Woof! Woof!

</pre>