在课堂上添加常规非反义函数

Question

I wanted to add functions to class, those functions are in separate file(s), those functions contain ($this).

class myClass {
    private $myFunctions=array(); // will contain two keys (title, function_object)
    private $var;

    public function __construct() {
        $this->var = 'Hello world';
    }

    public function add_function($title, $func) {
        $this->myFunctions[$title] = $func;
    }

}

function add($x, $y)    {
    echo $this->var; 
    return $x + $y; 
}

$class = new myClass;
$class->add_function('add', 'add()');

echo $class->add(1,2);

my goal is to add regular functions (not anonymous functions) to the class or to assign those function(s) to a var which can be passed to the class!

Can this be achieved ?

Answer 1

You must have to understand the oops concepts here.

$this refers to your current class / object. So all functions inside a class will be able to access $this ( Current Object ).

But the function declared out side of class can not use $this of that object. (Are you clear up to here.)

But anyways nothing is impossible.

You can achieve your goal in at-least 2 ways.

2) You can use trait to implement multiple inheritance.

it will be like this

trait commonFunctions
{

    function add($a, $b)
    {
        $this->result = $a + $b;

        return $this;
    }
}

class myClass
{

    use commonFunctions;

    public function myClassFunction()
    {
        // 
    }
}

2 ) Or you can follow below code. Source php.net

<?php

class A {
    function __construct($val) {
        $this->val = $val;
    }
    function getClosure() {
        //returns closure bound to this object and scope
        return function() { return $this->val; };
    }
}

$ob1 = new A(1);
$ob2 = new A(2);

$cl = $ob1->getClosure();
echo $cl(), "
";
$cl = $cl->bindTo($ob2);
echo $cl(), "
";

Here __call will be called when undeclared method is being called. So you can dynamically append methods to class by this way.

Of course you can polyfill your object in javascript like way. But keep in mind you need to use Reflection to bind this to closure.

<?php

class A {

    private $dynamic_functions=[];

    public function __call($method, $args=[])
    {
        if(isset($this->dynamic_functions[$method]) && $this->dynamic_functions[$method] instanceof \Closure)
        {
            $cl = $this->dynamic_functions[$method]->bindTo($this);

            return call_user_func_array($cl, $args);
        }
        else
        {
            die("Wrong method, Not yet polyfilled.");
        }
    }

    public function __set($property, $value)
    {
        $this->dynamic_functions[$property] = $value;
    }
}

$a = new A;

$a->sum = function($a,$b){

    // var_dump($this); will give you current instance of A

    return $a+$b;
};

echo $a->sum(5, 3);