Do variable functions get overwritten by actual functions?

Question

I know that you can call functions using variable names like this:

$foo = "bar";
function bar()
{
    echo "test";
}
$foo(); // echos test

I am wondering if in a class, an actual function overrides that.
If I had this class:

class myClass{
    public $test;
    public function __construct()
    {
         $this->test = new myOtherClass;
    }
    public function test()
    {
         echo "foo";
    }
}

Would both of these work correctly?

$obj->test(); // echo foo
$obj->test->method(); // access a method of myOtherClass

Edit: The original idea for this was that myOtherClass held a class with one main function that was accessed all the time, and a few other less accessed ones. I could use test() to link the main function to the class so there is less typing. But given the first answer I'll probably stick away from that.

Answer 1

I don't know PHP well enough to answer your question, but I spent several years maintaining products and would like to point out a serious difficulty with maintainability with this. Consider that you have the question as to whether this will even work properly. Now consider that the person maintaining your code will (a) have the same question as you and (b) probably not read the whole class (unless it's a very small class). And if you're changing $test from outside the class, it will be even more difficult to understand.

While this is an interesting question, especially from an academic point of view, it's a terrible practice from a maintenance point of view. Please use different variable names for different purposes; for example, use $otherClass for the pointer to the other class and test() for the test function and your maintainers (including yourself, if you maintain your own code) will curse at you less :)

Answer 2

PHP allows different symbols with the same name. Object properties and methods are totally different things in PHP, unlike JavaScript and some other languages:

// all of them work OK

define('SomeClass', 'SomeClass');

function SomeClass () {}

class SomeClass {}

This causes ugly problems in PHP 5.3:

$foo = new StdClass;
$foo->bar = function () {
    return "bar";
};

$foo->bar(); // does not work, unfortunately :(

Answer 3

You wrote:

$obj->test(); // echo foo
$obj->test->method(); // access a method of myOtherClass

Right, this is how it works. You're not using anything variable in there.

$obj->test;    // member variable $test of $obj
$obj->test();  // method test() of $obj
$obj->$test(); // variable function, result depends on content of $test

$obj->test()->otherTest();    // invokes otherTest() on an object
                              // returned by $obj->test()

$foo = 'test';
$bar = 'otherTest';
$obj->$foo()->$bar();         // same as above, but please, for the love of God,
                              // don't ever use this. ;)