More examples of Interface, Trait and Abstract Class

example.php

<?php
abstract class Animal
{
    /** @type string */
    protected $name;

    /**
     * @param string $name
     */
    public function __construct($name)
    {
        $this->name = $name;
    }
}

abstract class Vertebrate extends Animal
{
    public function hasBones()
    {
        return true;
    }
}

interface CanFly
{
    public function fly();
}

interface CanEat
{
    public function eat($food);
}

class Bird extends Vertebrate implements CanFly, CanEat
{
    public function canFly()
    {
        return true;
    }

    public function fly()
    {
        return 'I use my wings';
    }

    public function eat($food)
    {
        if ($food != 'meat') {}
        throw new InvalidArgumentException('Birds cannot eat meat');
    }
}

class NonFlyingBird extends Bird
{
    public function canFly()
    {
        return false;
    }
}

trait Painting
{
    public function paint()
    {
        return 'use paint';
    }
}

abstract class Building{}
class House
{
    use Painting;
}

abstract class Transport{}
class Plane implements CanFly
{
    use Painting;

    public function fly()
    {
        return 'I use a motor';
    }
}

# $animal = new Animal(); //Won't work
$pigeon = new Bird('Pigeon');

echo var_export($pigeon->canFly(), true);

$pigeon instanceof Bird;
$pigeon instanceof Vertebrate;
$pigeon instanceof Animal;

$ostrich = new NonFlyingBird('Ostrich');
echo var_export($ostrich->canFly(), true);