Stack local functions in PHP

Recently, in one of my projects I needed to pass a local function to "stack" it.

What is a local function?

In php a local function is a function within a function

	<?php
	function main() {
	//Some code can go here
	function local() {
	//This function does something
	}
	//Some code can go here which can call local();
	}

view raw local_function.php hosted with ❤ by GitHub

What I needed?

Well, basically I needed is to stack function calls in a list, so I could call it later.

In PHP you have the callable type, and you can call any function that is globally accessible or a method of an object which is globally accessible, knowing the function's name.

The solution

I used an interface to do something like this:

	<?php
	/**
	* Example showing how to stack functions and call them later.
	* Just as Javascript addEventListener would do: Passing functions like callable objects
	* Solution if functions are "local" and not globally available
	**/
	interface mycallable {
	public function call($param);
	}
	var $stack = [];
	/**
	* This function will push the function into the array, with some basic validation
	**/
	function pushFunction( &$afunction ) {
	global $stack;
	if( $afunction instanceof mycallable ) {
	$stack[] = $afunction;
	} else {
	throw new Exception('trying to push something that is not a mycallable');
	}
	}
	/**
	* This function will call all stacked functions
	**/
	function callStackedFunctions() {
	global $stack;
	foreach( $stack as $afunction ) {
	$afunction->call(null);
	}
	}
	/**
	* This functions does real things
	**/
	function doThings() {
	//Some code here
	if( $condition ) {
	class aFunction implements mycallable {
	public function call($param) {
	//do some stuff
	}
	}
	$variable = new aFunction();
	} else {
	class bFunction implements mycallable {
	public function call($param) {
	//do other stuff
	}
	}
	$variable = new bFunction();
	}
	pushFunction($variable);
	}

view raw stacking_functions.php hosted with ❤ by GitHub

What do you thing?
Have I done an complicated workaround just to skip doing a function globally available and protected by a namespace?

Comments

[kip]

I think maybe your solution is apply Strategy Pattern or State Pattern, you need to analyze your situation and make the choice.

BTW function pushFunction( &$afunction ) { isn't neccesary, in PHP objects are assigned to variables with a identifier point, the same point always unless you clone the object.

A PHP reference is an alias, which allows two different variables to write to the same value. As of PHP 5, an object variable doesn't contain the object itself as value anymore. It only contains an object identifier which allows object accessors to find the actual object. When an object is sent by argument, returned or assigned to another variable, the different variables are not aliases: they hold a copy of the identifier, which points to the same object.
php.net/manual/en/language.oop5.re...

[Eduard Llach]

Good points!

The goal in the real project is different, and i'm not sure at all that Startegy pattern or State Patter will do what I was looking for.

But you've shown me an interesting new site! designpatternsphp.readthedocs.io

And true, & is not necessary here.

Thx!