CODEWITHSUNDEEP
php
meYnot
meYnot

Reputation: 342

Assign functions from another file to a Class

I am trying to add functions to class from a separate file, I wonder if this could be possible!

$mClass = new MyClass();
$mClass->new_Functions[0](10);  // Is there a way to have it in this form?

class myClass
{
    private $Pvar = 5;
    $new_Fcuntions;
    function __construct()
    {
        include('additional.functions.php');
        $arr = get_defined_functions();
        $this->new_Functions = $arr['user'];
        // trying to call the function with parameter 10
        call_user_func(array($this, $this->new_Functions[0]), 10);
    }

}

[additional.functions.php] file

function operate($y)
{
    return $this->Pvar * $y;
}

----- Edited ------- as it wasn't clear! "additional.functions.php" is a module and there will be multiple modules to be added to the application, and every module could have more than single function and modules could call one another!

additional.functions.php [module file]

function operate($y)
{
    return $this->Pvar * $y;
}

function do-more($foo)
{
    return $this->operate(20) + $foo;
}

another.functions.php [another module]

function do-another($foo)
{
    return $this->do-more(30) - $foo;
}

function add($foo, $bar)
{
    return $foo + $bar;
}

appreciate every participation, its been a while since I am trying to maneuver around with it! Is this possible or should I give up!

Upvotes: 0

Views: 168

Answers (6)

stofl
stofl

Reputation: 2982

If you want to extend MyClass from your modules (and not to initialize it, like in your example code), than you could do it in a way like this:

<?php

namespace modules\MyModuleA;

class MyClassExtension
{
    private $MyObject;

    public function __construct(\MyClass $MyObject)
    {
        $this->MyObject = $MyObject;
    }

    public function doSomething($anyParameter)
    {
        return $this->MyObject->doSomethingElse($anyParameter * 5, 42, 'foo');
    }
}

And MyClass:

<?php

class MyClass extends \Extensible
{
    // some code
}

abstract class Extensible
{
    private $extensions = [];

    public function extend($extension)
    {
        $this->extensions[] = $extension;
    }

    public function __call($methodName, $parameters)
    {
        foreach ($this->extensions as $Extension) {
            if (in_array($methodName, get_class_methods($Extension))
                return call_user_func_array([$Extension, $methodName], $parameters);
        }
        throw new \Exception('Call to undefined method ' . $methodName . '...');
    }

    public function hasExtension($extensionName)
    {
        return in_array($this->extensions, $extensionName);
    }
}

And put it all together:

<?php

$moduleNames = ['MyModuleA', 'MyModuleB'];

$MyObject = new \MyClass;

foreach ($moduleNames as $moduleName) {
    $className = '\\modules\\' . $moduleName . '\\MyClassExtension';
    $module = new $className($MyObject);
    $MyObject->extend($module);
}

// Now you can call a method, that has been added by MyModuleA:

$MyObject->doSomething(10);

You should add an interface for the extension classes of course...

The problem is: What happens if any code in your application calls a method of $MyObject, that is not there, because the module has not been loaded. You would always have to check if ($MyObject->hasExtension('ModuleA')) { ... }, but, of course, the application shouldn't be aware of any module. So I would not design an application in such a way.

Upvotes: 1

stofl
stofl

Reputation: 2982

Maybe this approach helps you:

In the files with the additional functions, don't define named functions, but return a closure, that expects (at least) the object (instance of MyClass) as parameter:

<?php

// additional.functions.php

return function ($myObject) {
    $Object->multiplyPvar($myObject->getTheNumber());
    $Object->doSomethingElse(42, 'foo');
};

The client, that builds MyClass collects those functions from the files into the array:

<?php

$files = [
    '/path/to/my/additional.functions1.php',
    '/path/to/my/additional.functions2.php'
];

$initFunctions = [];
foreach ($files as $path)
    $initFunctions[] = include $path;

$MyObject = new \MyClass($initFunctions);

The constructor then calls those functions:

<?php

class MyClass
{
    public function __construct(array $additionalInitFunctions)
    {
        foreach ($additionalInitFunctions as $additionalInitFunction)
            $additionalInitializerFunction($this); // you can also add parameters of course
    }
}

This way the class keeps very well testable as well as the function files. Maybe this could help you in any way. You should never ever think about modifying the internal (private) state of an object directly from any code from outside of the class. This is not testable! Think about writing tests before you implement your code (called "test driven development"). You will see, it is not possible to test a class, if you allow any code outside of that class to modify the internal (private) state of the class instance. And you don't want to have this. If you change some internal implementation detail in your class without breaking the unit test of that class, you will anyways probably break some code in any of your additional.functions.php files and no test will tell you: "Hey: you've broken something right now".

Upvotes: 0

Paul Carlton
Paul Carlton

Reputation: 2993

I got it to work with dependency injection. The pvar has to be public or create a __get method to return the private variable. I also used the function name because it seems cleaner to me to use it via name rather than it's position in the list but if you want to keep that then just put $key where you see $value from the line: $this->function_list[$value] = ...

function operate($y, $that)
{
    return $that->Pvar * $y;
}

class Example {

    public $function_list = array();
    private $Pvar = 5;
    public function __construct()
    {
        $list = get_defined_functions();
        $that = $this;
        foreach ($list['user'] as $key => $value) {
            $this->function_list[$value] = function() use ($value, $that) {
                print call_user_func_array($value, array_merge(func_get_args(), array($that )));
            };
        }
    }
    public function __get($key)
    {
        if (isSet($this->$key)) {
            return $this->$key;
        } else {
            throw new \Exception('Key "'.$key.'" does not exist');
        }
    }
}

$Ex = new Example();

$Ex->function_list['operate'](10);

Upvotes: 1

Łukasz
Łukasz

Reputation: 643

If you can have another class in that file instead of file with functions - the best solution will be Traits http://php.net/manual/en/language.oop5.traits.php or using inheritance

If you move that code to class you can avoid a lot of unnecessary code. I mean:

include('additional.functions.php');
$arr = get_defined_functions();
$this->new_Functions = $arr['user'];
// trying to call the function with parameter 10
call_user_func(array($this, $this->new_Functions[0]), 10);

It'll be e.g.:

class myClass extends MyBaseClassWithMyAwesomeFunctions
{
    private $Pvar = 5;
}

Upvotes: 0

ArunasR
ArunasR

Reputation: 2005

I would suggest to use traits (mix-ins). See PHP reference

Upvotes: 0

Shon M
Shon M

Reputation: 174

It looks to me like you are looking for Traits, which are a new feature as of PHP 5.4.0. Using traits, you can have snippets of code "mixed in" to other classes, a concept known as "horizontal reuse".

If you are not looking for traits, it's possible that you could do what you wanted with Runkit, however I would suggest staying as far away from it as possible, if you are not genuinely interested in PHP internals as well.

In any event, whatever you are trying to do is very interesting

Upvotes: 1

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