How do I immediately execute an anonymous function in PHP?
PhpJavascriptFunctionPhp Problem Overview
In JavaScript, you can define anonymous functions that are executed immediately:
(function () { /* do something */ })()
Can you do something like that in PHP?
Php Solutions
Solution 1 - Php
For versions prior to PHP 7, the only way to execute them immediately I can think of is
call_user_func(function() { echo 'executed'; });
With current versions of PHP, you can just do
(function() { echo 'executed'; })();
Solution 2 - Php
In PHP 7 is to do the same in javascript
$gen = (function() {
yield 1;
yield 2;
return 3;
})();
foreach ($gen as $val) {
echo $val, PHP_EOL;
}
echo $gen->getReturn(), PHP_EOL;
The output is:
1
2
3
Solution 3 - Php
Well of course you can use call_user_func, but there's still another pretty simple alternative:
<?php
// we simply need to write a simple function called run:
function run($f){
$f();
}
// and then we can use it like this:
run(function(){
echo "do something";
});
?>
Solution 4 - Php
This is the simplest for PHP 7.0 or later.
(function() {echo 'Hi';})();
It means create closure, then call it as function by following "()". Works just like JS thanks to uniform variable evaluation order.
Solution 5 - Php
(new ReflectionFunction(function() {
// body function
}))->invoke();
Solution 6 - Php
Note, accepted answer is fine but it takes 1.41x as long (41% slower) than declaring a function and calling it in two lines.
[I know it's not really a new answer but I felt it was valuable to add this somewhere for visitors.]
Details:
<?php
# Tags: benchmark, call_user_func, anonymous function
require_once("Benchmark.php");
bench(array(
'test1_anonfunc_call' => function(){
$f = function(){
$x = 123;
};
$f();
},
'test2_anonfunc_call_user_func' => function(){
call_user_func(
function(){
$x = 123;
}
);
}
), 10000);
?>
Results:
$ php test8.php
test1_anonfunc_call took 0.0081379413604736s (1228812.0001172/s)
test2_anonfunc_call_user_func took 0.011472940444946s (871616.13432805/s)
Solution 7 - Php
This isn't a direct answer, but a workaround. Using PHP >= 7. Defining an anonymous class with a named method and constructing the class and calling the method right away.
$var = (new class() { // Anonymous class
function cool() { // Named method
return 'neato';
}
})->cool(); // Instantiate the anonymous class and call the named method
echo $var; // Echos neato to console.
Solution 8 - Php
I tried it out this way, but it's more verbose than the top answer by using any operator (or function) that allows you to define the function first:
$value = $hack == ($hack = function(){
// just a hack way of executing an anonymous function
return array(0, 1, 2, 3);
}) ? $hack() : $hack();
Solution 9 - Php
Not executed inmediately, but close to ;)
<?php
$var = (function(){ echo 'do something'; });
$var();
?>