Introduction to Closures in Php. in start.php we bind a closure to a class instance. In firstclosure.php we pass a closure to a class method in callable.php we improve the firstclosure.php class and finally in laravelstyle we explore how to call methods in laravel style read the blog at http://codedcell.com

callable.php

<?php

/**
 * Created by PhpStorm.
 * User: dwanyoike
 * Date: 03/03/15
 * Time: 09:29
 */
class Addition
{
    private $valueA;
    private $valueB;
    private $valueC;
    private $sum;

    public function AddNumbers()
    {
        $this->sum = $this->valueA + $this->valueB + $this->valueC;
        return $this->sum;

    }

    /**
     * Checks if function argument is Closure and callback and runs the function
     * @param $callback
     * @return mixed
     */
    private function  runCallback($callback)
    {
        if ($callback instanceof Closure and is_callable($callback)) {
            return $callback();
        }
    }

    public function setValueA($valueA)
    {
        $valueA = $this->runCallback($valueA);
        $this->valueA = $valueA;
    }

    public function setValueB($valueB)
    {
        $valueB = $this->runCallback($valueB);
        $this->valueB = $valueB;
    }

    public function setValueC($valueC)
    {
        $valueC = $this->runCallback($valueC);
        $this->valueC = $valueC;
    }
}

//Get the sum of the area of  three circles
$instanceCircle = new Addition();

$instanceCircle->setValueA(function () {
    return pi() * 14;
});
$instanceCircle->setValueB(function () {
    return pi() * 36;
});
$instanceCircle->setValueC(function () {
    return pi() * 44;
});

var_dump($instanceCircle->AddNumbers());

firstclosure.php

<?php

/**
 * Created by PhpStorm.
 * User: dwanyoike
 * Date: 03/03/15
 * Time: 09:29
 */
class Addition
{
    private $valueA;
    private $valueB;
    private $valueC;
    private $sum;

    public function AddNumbers()
    {
        $this->sum = $this->valueA + $this->valueB + $this->valueC;
        return $this->sum;

    }

    public function setValueA($valueA)
    {
        $this->valueA = $valueA;
    }

    public function setValueB($valueB)
    {
        $this->valueB = $valueB;
    }

    public function setValueC($valueC)
    {
        $this->valueC = $valueC;
    }
}
//Get the sum of the area of  three circles
$instanceCircle = new Addition();
$circleArea = function($radius){
    return pi()*$radius;
};
$instanceCircle->setValueA( $circleArea(14));
$instanceCircle->setValueB($circleArea(36));
$instanceCircle->setValueC($circleArea(44));
var_dump($instanceCircle->AddNumbers());

laravelstyle.php

<?php

/**
 * Created by PhpStorm.
 * User: dwanyoike
 * Date: 03/03/15
 * Time: 09:29
 */
class Addition
{
    private $valueA;
    private $valueB;
    private $valueC;
    private $sum;

    public function AddNumbers($callback = null)
    {
        if ($callback instanceof Closure) {
            call_user_func($callback, $this);
        }
        $this->sum = $this->valueA + $this->valueB + $this->valueC;
        return $this->sum;
    }

    public function setValueA($valueA)
    {
        $this->valueA = $valueA;
    }

    public function setValueB($valueB)
    {
        $this->valueB = $valueB;
    }

    public function setValueC($valueC)
    {
        $this->valueC = $valueC;
    }

    public function total()
    {
        return $this->sum;
    }
}

//Normal Usage of classes
$instanceA = new Addition();
$instanceA->setvalueA(120);
$instanceA->setvalueB(110);
$instanceA->setvalueC(150);
var_dump($instanceA->AddNumbers());

//Closure usage of class
$instanceB = new Addition();
$val = $instanceB->AddNumbers(function ($x) {
    $x->setvalueA(120);
    $x->setvalueB(110);
    $x->setvalueC(150);
});
var_dump($val);

start.php

<?php

/**
 * Created by PhpStorm.
 * User: dwanyoike
 * Date: 03/03/15
 * Time: 09:29
 */
class Addition
{
    private $valueA;
    private $valueB;
    private $valueC;
    private $sum;

    public function AddNumbers()
    {
        $this->sum = $this->valueA + $this->valueB + $this->valueC;
        return $this->sum;

    }
    public function setValueA($valueA)
    {
        $this->valueA = $valueA;
    }

    public function setValueB($valueB)
    {
        $this->valueB = $valueB;
    }

    public function setValueC($valueC)
    {
        $this->valueC = $valueC;
    }
}

//Normal Usage of classes
$instanceA = new Addition();
$instanceA->setValueA(10);
$instanceA->setValueB(10);
//setValueC
$ourClosure =  function ($valueC)
{
    $this->valueC = $valueC;
};

//bind our closure to a method and a class
$closure = Closure::bind($ourClosure,$instanceA,'Addition');
$closure(24);
var_dump($instanceA->AddNumbers());