내부 (내장) 함수
To recursively call a closure, use this code.
<?php
$recursive = function () use (&$recursive){
// The function is now available as $recursive
}
?>
This DOES NOT WORK
<?php
$recursive = function () use ($recursive){
// The function is now available as $recursive
}
?>
익명 함수
익명 함수는 이름을 지정하지 않은 함수를 생성할 수 있게 합니다. 콜백 인수에 매우 유용하나, 다른 용도로 사용할 수도 있습니다.
Example #1 익명 함수 예제
<?php
echo preg_replace_callback('~-([a-z])~', function ($match) {
return strtoupper($match[1]);
}, 'hello-world');
// 출력: helloWorld
?>
익명 함수는 내부적으로 Closure 클래스로 구현됩니다.
Note: 익명 함수는 PHP 5.3.0부터 사용할 수 있습니다.
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User Contributed Notes익명 함수
mike at blueroot dot co dot uk
29-Oct-2009 01:40
29-Oct-2009 01:40
kukoman at pobox dot sk
13-Oct-2009 09:22
13-Oct-2009 09:22
be aware of Fatal error: Using $this when not in object context when using in closures
http://wiki.php.net/rfc/closures/removal-of-this
gerard at visei dot nl
07-Oct-2009 11:41
07-Oct-2009 11:41
The text above the third example tries to explain that anonymous functions can inherit variables from the parent scope, but fails to properly explain how this is done: namely using the "use" keyword in the function definition.
The following page has a much more detailed explanation of closures in PHP 5.3:
http://wiki.php.net/rfc/closures
andrew at evilwalr dot us
03-Oct-2009 02:06
03-Oct-2009 02:06
Very easy way to get the netstat (windows)... yes, this could be a function, but as an example, here it is in closure form...
<?php
$netstat = function($return = null, $precision = 2) {
// supplement function
$_convert = function ($bytes) use ($precision) {
$i = 0; $iec = array('b', 'kb', 'mb', 'gb', 'tb', 'pb', 'eb', 'zb', 'yb');
while (($bytes / 1024) > 1): $bytes = $bytes / 1024; $i++; endwhile;
return round(substr($bytes, 0, strpos($bytes, '.') + 4), $precision) . ' ' . strtoupper($iec[$i]);
};
foreach (explode("\n", `netstat -e`) as $d) {
if (preg_match('/^Bytes([\s].+)([0-9])([\s].+)([0-9])/', $d, $m)) {
switch ($return) {
case 'sent': return $_convert(trim($m[1].$m[2])); break;
case 'recv': return $_convert(trim($m[3].$m[4])); break;
default: return array('sent' => $_convert(trim($m[1].$m[2])),
'recv' => $_convert(trim($m[3].$m[4]))); break;
}
}
}
};
?>
Jaakko Salmela
09-Sep-2009 07:52
09-Sep-2009 07:52
<?php
/**
* Using closures to dynamically extend objects
*
*/
class ClosureTest{
public $member = 'test';
protected $protectedMember = 'protectedtest';
public function __call($method, $args)
{
return call_user_func_array( $this->$method, $args);
}
}
$object = new ClosureTest();
$object->closure = function() use ($object){
return $object->member;
};
echo $object->closure();
//Output: 'test'
/**
* This won't work, you can not access protected/private members, which is fine.
*/
$object->closureAccessProtected = function() use ($object){
return $object->protectedMember;
};
$object->closureAccessProtected();
?>
dave at mausner dot us
11-Aug-2009 06:34
11-Aug-2009 06:34
Ulderico had it almost right. To avoid confusing the interpreter, when using a simple closure stored in a $variable, you must invoke the nameless function using the function syntax.
<?php
$helloworld = function(){
return "each hello world is different... ".date("His");
};
echo $helloworld( );
?>
Note the empty actual-parameter list in the "echo". NOW IT WORKS.
Anonymous
03-Aug-2009 06:50
03-Aug-2009 06:50
If you want to check whether you're dealing with a closure specifically and not a string or array callback you can do this:
<?php
$isAClosure = is_callable($thing) && is_object($thing);
?>
tom at r dot je
29-Jul-2009 07:51
29-Jul-2009 07:51
Unfortunately, you can't get a pointer to a function, the only function pointers are ones which use anonymous functions as they're created.
This wont work:
<?php
$info = phpinfo;
$info();
//or
function foo() {
echo 'bar';
}
$foo = foo;
$foo();
?>
Because of the behavior of $foo(), it will assume $foo is a string, and try to run the function with the name stored in the string.
ulderico at maber dot com dot br
14-Jul-2009 11:43
14-Jul-2009 11:43
Perhaps you'll find yourself wanting doing a wicked thing like:
<?php
$helloworld = function(){
return "each hello world is different... ".date("His");
};
echo $helloworld;
?>
which throws:
Catchable fatal error: Object of class String could not be converted to string
OK... Here's the way of doing this.
<?php
class Helloworld{
function __toString(){
return("each hello world is different...".date("His"));
}
}
$helloworld = new Helloworld();
echo $helloworld;
sleep(5);
echo $helloworld;
?>
mcm dot matt at gmail dot com
30-Jun-2009 09:49
30-Jun-2009 09:49
Example using uasort.
<?php
// Usual method.
function cmp($a, $b) {
return($a > $b);
}
uasort($array, 'cmp');
// New
uasort($array, function($a, $b) {
return($a > $b);
});
?>
a dot schaffhirt at sedna-soft dot de
19-Jun-2009 06:55
19-Jun-2009 06:55
When using anonymous functions as properties in Classes, note that there are three name scopes: one for constants, one for properties and one for methods. That means, you can use the same name for a constant, for a property and for a method at a time.
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 $member;
public function member () {
return "method 'member'";
}
public function __construct () {
$this->member = function () {
return "anonymous function 'member'";
};
}
}
header("Content-Type: text/plain");
$myObj = new MyClass();
var_dump(MyClass::member); // int(1)
var_dump($myObj->member); // object(Closure)#2 (0) {}
var_dump($myObj->member()); // string(15) "method 'member'"
$myMember = $myObj->member;
var_dump($myMember()); // string(27) "anonymous function 'member'"
?>
That means, regular method invocations work like expected and like before. The anonymous function instead, must be retrieved into a variable first (just like a property) and can only then be invoked.
Best regards,