Is it possible to overwrite a function in PHP

Mark Lalor picture Mark Lalor · Sep 1, 2010 · Viewed 134.7k times · Source

Can you declare a function like this...

function ihatefooexamples(){
  return "boo-foo!";
};

And then redeclare it somewhat like this...

if ($_GET['foolevel'] == 10){
  function ihatefooexamples(){
    return "really boo-foo";
  };
};

Is it possible to overwrite a function that way?

Any way?

Answer

Peter Bailey picture Peter Bailey · Sep 1, 2010

Edit

To address comments that this answer doesn't directly address the original question. If you got here from a Google Search, start here

There is a function available called override_function that actually fits the bill. However, given that this function is part of The Advanced PHP Debugger extension, it's hard to make an argument that override_function() is intended for production use. Therefore, I would say "No", it is not possible to overwrite a function with the intent that the original questioner had in mind.

Original Answer

This is where you should take advantage of OOP, specifically polymorphism.

interface Fooable
{
    public function ihatefooexamples();
}

class Foo implements Fooable
{
    public function ihatefooexamples()
    {
        return "boo-foo!";
    }
}

class FooBar implements Fooable
{
    public function ihatefooexamples()
    {
        return "really boo-foo";
    }
}

$foo = new Foo();

if (10 == $_GET['foolevel']) {
    $foo = new FooBar();
}

echo $foo->ihatefooexamples();