Use variables inside an anonymous function, which is defined somewhere else
The point of the use
keyword is to inherit/close over a particular environment state from the parent scope into the Closure when it's defined, e.g.
$foo = 1;
$fn = function() use ($foo) {
return $foo;
};
$foo = 2;
echo $fn(); // gives 1
If you want $foo
to be closed over at a later point, either define the closure later or, if you want $foo
to be always the current value (2), pass $foo
as a regular parameter.
w00
Updated on June 03, 2022Comments
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w00 almost 2 years
When using anonymous functions in PHP, you can easily use variables from right outside of its scope by using the
use()
keyword.In my case the anonymous functions are already defined somewhere, but called later on (somewhere else) in a class.
The following piece of code is to illustrate the idea:
<?php $bla = function ( $var1 ) use ($arg) { echo $var1; }; class MyClass { private $func; public function __construct ( $func ) { $this->func = $func; } public function test ( $arg ) { $closure = $this->func; $closure ( 'anon func' ); } } $c = new MyClass($bla); $c->test ( 'anon func' );
What i'm doing is i create an
anonymous function
and store that in a variable. I pass that variable to the method of a class and that is where i want to run the anonymous function.But i can't use the
use()
keyword to get the$arg
parameter from themethod
this way. Because the anonymous function was declared outside of themethod
.But i really need a way to get the variables from the method where the anonymous function is run from. Is there a way to do that, when the anonymous function is declared somewhere else..?
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w00 over 11 yearsWas hoping there was something i overlooked. But appearently there is no other way then to pass the needed variables as parameter.
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newacct over 11 yearsyou should mention it's called "Lexical Scoping". All modern programming languages use lexical scoping.