Question

I am coming from the Ruby world and I have a PHP project I currently work on.

Like in Ruby scripts, is it possible to declare class methods in PHP? Basically, I’m asking what the equivalent of the following code would be in PHP

class A
  def hello; "hello from object"; end
  def self.hello; "hello from class"; end
end

Note the difference between the instance method and the class method.

Answer 1

In PHP class methods are usually referred to as static methods and are declared as such. To directly translate your example:-

class A
{
    public function hello()
    {
        return "hello from object";
    }

    //We can't have two methods with the same name.
    public static function s_hello()
    {
        return "hello from class";
    }
}

Then you would call the methods like this:-

//For a static method we don't need an instance
echo A::s_hello;
//But we do for an instance method
$a = new A();
echo $a->hello();

You can also have static properties, so the above example could be modified something like this:-

class A
{
    private static $s_hello = "hello from class";
    private $hello = "hello from object";

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

    //We can't have two methods with the same name.
    public static function s_hello()
    {
        return self::$hello;
    }
}

http://php.net/manual/en/language.oop5.static.php