Question

Ok, i know that probably this is not possible, but i’ll give it a try. Maybe my knowledge is not so good. Please don’t downvote, this is just for curiosity and this maybe due to a poor OO design.

Assume that class definition for A is:

class A
{
    public function build()
    {
        $data = $this->fetchData();
        ...
    }

    public function fetchData()
    {
        // Database eavy query
        return $this->repository->fetchDataForCharting();
    }
}

And then, without using a good and decent OO design, you create class B which is going to use fetchDataForCharting from the repository, for doing some other different calculations:

class B
{
    public $data;

    public function getMonthlyLimit()
    {
        // Database eavy query
        $data = $this->getData();
    }

    public function getData()
    {
        return isset($this->data) ? $this->data :
            $this->repository->fetchDataForCharting();
    }
}

Sometimes you need only A, sometimes you need only B, sometimes both. Is there any way of overriding fetchData at runtime? I mean someting like $.extend() in jQuery:

$b = new B();
$b->getMonthlyLimit(); // $b->data filled

$a = new A();

// Override fetchData
$a = extend($a, 'fetchData', function() use($b) { return $b->data; });

$a->build(); // Just 1 query

Answer 1

There is no proper way to modify/replace/add a class method.

The runkit extension has runkit_method_redefine() and runkit_method_add() but both are experimental and ugly (they take a code string, not a Closure object like your anonymous function is).