Experiment with functional patterns in PHP

curry.php

<?php

function curry() {
    $curryArgs = func_get_args();
    return function() use ($curryArgs){
        $function = array_shift($curryArgs);
        $mergedArgs = array_merge($curryArgs, func_get_args());
        return call_user_func_array($function, $mergedArgs);
    };
}


$multiply = function($x, $y) {
    return $x * $y;
};

$multiplyBy4 = curry($multiply, 4);

echo $multiplyBy4(2); // Echo: 8

memoization.php

<?php

class DynamicClosure {
    public static function execute(Closure $closure) {
        return call_user_func($closure);
    }
}


echo '<br/>Standard factorial<br/>';

function factorial($n) {
    echo 'call <br/>';
    if ($n == 0) {
        return 1;
    } else {
        return $n * factorial($n - 1);
    }
}

echo factorial(10) . '<br/>'; // called 11 times
echo factorial(11) . '<br/>'; // called 12 times
echo factorial(8)  . '<br/>'; // called 8 times

echo '<br/>Memoized factorial<br/>';

$memoizedFactorial = DynamicClosure::execute(function(){

    // results are cached in an array
    $results = array();

    // the function is passing itself as a bound variable
    return $factorial = function($n) use(&$results, &$factorial) {
        echo 'call <br/>';
        if (!isset($results[$n])) {
            if ($n == 0) {
                $results[$n] = 1;
            } else {
                $results[$n] = $n * $factorial($n - 1);
            }
        }
        return $results[$n];
    };
});

echo $memoizedFactorial(10) . '<br/>'; // called 11 times
echo $memoizedFactorial(11) . '<br/>'; // called only 2 times!
echo $memoizedFactorial(8) . '<br/>';  // called only 1 times!

module-pattern.php

<?php

class DynamicObject {

    /**
     * @var DynamicObject
     */
    public $prototype;

    public function __construct(array $attributes = array()) {
        foreach ($attributes as $name => $value) {
            $this->$name = $value;
        }
    }

    public function __get($varName) {
        if (!isset($this->$varName)) {
            return $this->prototype->$varName;
        }
    }

    public function __call($methodName, $params) {
        array_unshift($params, $this);
        if (isset($this->$methodName)) {
            return call_user_func_array($this->$methodName, $params);
        } else {
            return call_user_func_array($this->prototype->$methodName, $params);
        }
    }

    public static function extend(DynamicObject $prototype, $attributes = array()) {
        $child = new self($attributes);
        $child->prototype = $prototype;
        return $child;
    }

    public static function execute(Closure $closure) {
        return call_user_func($closure);
    }

}

$dialogsModule = DynamicObject::execute(function() {

    // private stuff
    $self = new DynamicObject(array(
        'privateName' => 'Piggy',
        
        'addNewLine' => function($me) {
            echo '<br/>';
        }
    ));

    // public stuff
    return new DynamicObject(array(
        'publicName' => 'Mickey Mouse',
        
        'sayHello' => function($me) use(&$self) {
            echo 'hi';
            $self->addNewLine();
            echo 'hello';
            $self->addNewLine();
        },

        'sayName' => function($me) use(&$self) {
            echo 'My public name is:' . $me->publicName;
            $self->addNewLine();
            echo 'My private name is:' . $self->privateName;
            $self->addNewLine();
        }
    ));
});


echo $dialogsModule->publicName . '<br/>'; // Echo: Mickey Mouse
$dialogsModule->sayHello(); // Echo: hi<br/>hello
$dialogsModule->sayName(); // Echo: My public name is: Micket Mouse <br/> My private name is: Piggy

prototypal-inheritance.php

<?php

class DynamicObject {

    /**
     * @var DynamicObject
     */
    public $prototype;

    public function __construct(array $attributes = array()) {
        foreach ($attributes as $name => $value) {
            $this->$name = $value;
        }
    }

    public function __get($varName) {
        if (!isset($this->$varName)) {
            return $this->prototype->$varName;
        }
    }

    public function __call($methodName, $params) {
        array_unshift($params, $this);
        if (isset($this->$methodName)) {
            return call_user_func_array($this->$methodName, $params);
        } else {
            return call_user_func_array($this->prototype->$methodName, $params);
        }
    }

    public static function extend(DynamicObject $prototype, $attributes = array()) {
        $child = new self($attributes);
        $child->prototype = $prototype;
        return $child;
    }

}

$animal = new DynamicObject(array(
            'age' => 0,
            'name' => 'El Barto',
            'breathe' => function($me) {
                echo $me->name . " is breathing<br/>";
            }
        ));


$animal->breathe(); // Echo: El Barto is breathing

///////////////////////////////////////////////////////////////////////////////
// Prototypal inheritance: an object extend another object
//

$cat = DynamicObject::extend($animal, array(
            'breathe' => function($me) {
                echo $me->name . " is purring<br/>";
            }
        ));

$cat->breathe(); // Echo: El Barto is purring


// Modifyng the prototype dynamically change the child too

$animal->eat = function($me){
    echo 'Gnam!<br/>';
};

$cat->eat(); // Echo: Gnam