Behave!
In favour of behaviours in OOP
Urban Etter
OOP in school
class Animal { ... }
class Cat extends Animal { ... }
$kitten = new Cat();
$kitten
is of type
Cat
Let the animals jump!
4 legs
2 legs
Types of classes
- Representers
- Doers
- Plumbers
- Translators
- Makers
'type of'
only really works
for representers
What if there is a
better way
to look at OOP?
Behaviours
Specification vs Implementation
What vs How
Specification or Implementation
- Interface: Specification
- Trait: Implementation
- Class: Specification and Implementation
// Represents a cat
class Cat {
public $name;
}
// Specification of behaviour 'jump'
interface CanJump {
public function jump();
}
// Implementation of behaviour 'jump'
class FourLeggedJumper implements CanJump {
public function jump() {
...
}
}
class Cat implements CanJump {
// @var CanJump
private $jumper;
public function jump() {
$this->jumper->jump();
}
}
$runner = new FourLeggedJumper();
$kitten = new Cat();
$kitten->setJumper($jumper);
$kitten->jump();
$fourLegs = new FourLeggedJumper();
$twoLegs = new TwoLeggedJumper();
$kitten = new Cat($fourLegs);
$doggie = new Dog($fourLegs);
$ralf = new Human($twoLegs);
if ($forrest instanceof CanJump)
$forrest->jump();
Impacts
- More entities (more complex for easiest use case, way better for real life)
- Seperation between specification and implementation
- Mix and match behaviours
- Better readability and maintainability