Basic example for create_function()

array_filter_closure.php

<?php
$array = array(1,2,3,4,5);
$v= 4;
$result = array_filter($array,function($n) use(&$v){return $v === $n;});
print_r($reslt);
?>

bad_closure.php

<?php
//Bad closure.
$fact = function($n) {
if($n>=1) 
   return 1;
else
   return $n*$fact(n-1);
}
echo $fact(5);  // Output : Error
?>

closure_factorial.php

<?php
$factorial = function($n) use (&$factorial) {
      if ($n <= 1)
        return 1;
      else
        return $n * $factorial($n - 1);
};
echo $factorial(5); //Output : 120
?>

create_function.php

<?php
$sum = create_function('$a,$b','return $a+$b;');
echo $sum(2,3); //Output : 5
?>

js_factorial.js

var fact = function(n) {
    if(n <= 1)
        return 1;
    else 
        return n*fact(n-1);
};

alert(fact(5)) // Output : 120

lambda_factorial.php

<?php
//Classic Y-combinator function
function Y($F) {
    $func =  function ($f) { return $f($f); };
    return $func(function ($f) use($F) {
            return $F(function ($x) use($f) {
            $ff = $f($f);
            return $ff($x);
        });
    });
}
//Anonymous factorial function using Y-combinator
$factorial = Y(function($fact){
       return function($n) use($fact) {
           if($n<=1)
               return 1;
           else
               return $n*$fact($n-1);
       };
});
echo $factorial(5); //Output : 120

?>

math_closure.php

<?php
//Simple math class 
class Math
{
    function  __construct($a) {
        $this->a =$a;
    }
    //Returns a closure
    function mul()
    {
        //We can't directly use $this inside closure
        $self = $this;
        return function($n) use($self) {
            return $n*$self->a;
        };
    }
}
$math = new Math(5);
$mul = $math->mul();
echo $mul(4); //Output : 20
?>

prototype_class.php

<?php
//This class demonstrate a way of prototyping 
//applications using closures
Class Hello
{
    public $name;
    public $methods;
        Public function __call($method, $args)
        {
            return call_user_func_array($this->methods[$method], $args);
        }
        public function  __set($name, $value) 
        {
            $this->methods[$name] = $value ;
        }
}
$hello= new Hello();
$hello->name = 'User';
$hello->greet = function() use ($hello) {
    return 'Hello '.$hello->name;
};

echo $hello->greet(); //Output : Hello User
?>

simple_lambda.php

<?php
$sum = function($a,$b) {
   return $a+$b;
};
echo $sum(2,3); //Output : 5
?>

In array_filter_closure.php you have a typo. $reslt should be $result.