PHP does not support method overloading. In case you've never heard of method overloading, it means that the language can pick a method based on which parameters you're using to call it. This is possible in many other programming languages like Java, C++.

So, under normal circumstances, you can't do this in PHP:

class Foo
{
   function bar(A $baz)
   {
      ...
   }

   function bar(B $baz)
   {
      ...
   }
}

However, with some clever coding, Adam Wathan made a trait, aptly called Overloadable, that makes method overloading possible. It works by just accepting any parameters using the splat operator and then determining which of the given functions must be called according to the given parameters.

Let's rewrite that example above using the Overloadable trait.

class Foo
{
    use Overloadable;

    function bar(...$arguments)
    {
        return $this->overload($arguments, [
            function (A $baz) {
               $this->functionThatProcessesObjectA($baz);
            },
            function (B $baz) {
               $this->functionThatProcessesObjectB($baz);
            },
        ]);
    }
}

Pretty cool stuff. In a gist on GitHub Adam shares a couple of examples, the source code of the trait and the tests that go along with it. Check it out!

https://gist.github.com/adamwathan/120f5acb69ba84e3fa911437242796c3