So you will need to explicitly pass them in by reference if your closure cares about their contents over time:

<?php
$result = 0;$one = function()
{ var_dump($result); };$two = function() use ($result)
{ var_dump($result); };$three = function() use (&$result)
{ var_dump($result); };$result++;$one(); $two(); $three(); ?>

<?php
$myInstance = null;$broken = function() uses ($myInstance)
{
if(!empty($myInstance)) $myInstance->doSomething();
};$working = function() uses (&$myInstance)
{
if(!empty($myInstance)) $myInstance->doSomething();
}if(SomeBusinessLogic::worked() == true)
{
$myInstance = new myClass();
}$broken(); $working(); ?>

<?php
$value = 0;
$fn = function &() use (&$value) { return $value; };$x =& $fn();
var_dump($x, $value); ++$x;
var_dump($x, $value);

Creating new lambda with function() { ... }; expression creates new instance of its static variables. Assigning a lambda to a variable does not create a new instance. A lambda is object of class Closure, and assigning lambdas to variables has the same semantics as assigning object instance to variables.

Example script: $a and $b have separate instances of static variables, thus produce different output. However $b and $c share their instance of static variables - because $c is refers to the same object of class Closure as $b - thus produce the same output.

#!/usr/bin/env php

Route::get('/tags/{tag}', function (string $tag) use ($posts): View {

return view('tags.show', [

As you can see I can make the code more verbose in the closures by type hinting the parameters and the return type. use however doesn't allow type hinting.

<?php
$count = 1;
$add = function($count) use (&$add){
$count += 1;
if($count < 10) $count = $add($count); return $count;
};
echo $add($count); ?>

Since a property can be also an anonymous function as of PHP 5.3.0, an oddity arises when they share the same name, not meaning that there would be any conflict.

Consider the following example:

<?php
class MyClass {
const member = 1;

public

public function

public function

<?php class Fun
{
protected function debug($message)
{
echo "DEBUG: $message\n";
}

public function

public function

=== Example 1 (passing by value) ===

Be careful, following code is not similar to previous code:

// And this technique is not working in loops:

=== Example 2 (passing by reference) ===

I decided to compare a single, saved closure against constantly creating the same anonymous closure on every loop iteration. And I tried 10 million loop iterations, in PHP 7.0.14 from Dec 2016. Result:

a single saved closure kept in a variable and re-used (10000000 iterations): 1.3874590396881 seconds

new anonymous closure created each time (10000000 iterations): 2.8460240364075 seconds

In other words, over the course of 10 million iterations, creating the closure again during every iteration only added a total of "1.459 seconds" to the runtime. So that means that every creation of a new anonymous closure takes about 146 nanoseconds on my 7 years old dual-core laptop. I guess PHP keeps a cached "template" for the anonymous function and therefore doesn't need much time to create a new instance of the closure!

So you do NOT have to worry about constantly re-creating your anonymous closures over and over again in tight loops! At least not as of PHP 7! There is absolutely NO need to save an instance in a variable and re-use it. And not being restricted by that is a great thing, because it means you can feel free to use anonymous functions exactly where they matter, as opposed to defining them somewhere else in the code. :-)

<?php
$type = 'number';
var_dump( ...( function() use ($type) {
if ($type=='number') return [1,2,3];
else if ($type=='alphabet') return ['a','b','c'];
} )() );
?>

<?php
class Test
{
public $callable;

function

echo (

The main reason why you would not want automatic binding is that as long as the Closure object created for the anonymous function exists, it retains a reference to the object that spawned it, preventing the object from being destroyed, even if the object is no longer alive anywhere else in the program, and even if the function itself doesn't use $this.

<?phpclass Foo
{
public function __construct(private string $id)
{
echo "Creating Foo " . $this->id, "\n";
}
public function gimme_function()
{
return function(){};
}
public function gimme_static_function()
{
return static function(){};
}
public function __destruct()
{
echo "Destroying Foo " . $this->id, "\n";
}
}

echo

echo

<?php
class Foo {
public function bar() {
static $anonymous = null;
if ($anonymous === null) {
$anonymous = function () {
return $this;
};
}
return $anonymous();
}
}$a = new Foo();
$b = new Foo();
var_dump($a->bar() === $a); var_dump($b->bar() === $a); ?>

To get the behaviour you're probably expecting, you need to pass the $this context into the function.

<?php
class Foo {
public function bar() {
static $anonymous = null;
if ($anonymous === null) {
$anonymous = function (self $thisObj) {
return $thisObj;
};
}
return $anonymous($this);
}
}$a = new Foo();
$b = new Foo();
var_dump($a->bar() === $a); var_dump($b->bar() === $a); ?>

The most useful tool in this snippet is the requesting_class() function that will tell you which class is responsible for executing the current Closure().

Overview:

Failure: reference anything through $this->

<?phpfunction requesting_class()
{
foreach(debug_backtrace(true) as $stack){
if(isset($stack['object'])){
return $stack['object'];
}
}

}

class

function

public function

echo

die();

<?php
$isAClosure = is_callable($thing) && is_object($thing);
?>