Calling Nested Lambda Function in PHP

Question

is that possible to call lambda function in nesting way

<?php
$func=function() use($something,$func /** as you know it will be undefined so what could be other way arround**/){
  if($something){
       $func();
  }
}

these are allowed http://stackoverflow.com/questions/3737139/reference-what-do-various-symbols-mean-in-php?rq=1 but real problems not allowed. — dev.meghraj, Jul 26 '16 at 20:06
So in a definition of something you want to use the above said something? — u_mulder, Jul 26 '16 at 20:06

score 5 · Accepted Answer · answered Jul 26 '16 at 20:06

5

$func is not defined yet when you pass it to $func. $func will only be defined right after the function definition, which is a little bit too late for this to work.

The easy work around is as follows:

$func = null;
$func = function() use (&$func) {

}

answered Jul 26 '16 at 20:06

Evert

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1

good one... I'd never thought of using references for this... – Marc B Jul 26 '16 at 20:08
me too............. – dev.meghraj Jul 26 '16 at 20:11

score 0 · Answer 2 · answered Jul 26 '16 at 20:07

use $func can't succeed, because $func won't be defined until AFTER the lambda creation has completed and returned the lamba. PHP cannot time travel.

You also cannot do something like:

$func = '';
$func = function() use $something, $func ....;

While that gets around the $func is not defined, it also "locks" the value of $func into the lambda at the time the lambda's created:

php > $foo = 'bar';
php > $baz = function() use($foo) { echo $foo; };
php > $baz();
bar
php > $foo = 'qux';
php > $baz();
bar

Calling Nested Lambda Function in PHP

2 Answers2