I have seen code like this:
function($cfg) use ($connections) {}
but php.net doesn't seem to mention that function. I'm guessing it's related to scope, but how?
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3 Answers
use is not a function, it's part of the Closure syntax. It simply makes the specified variables of the outer scope available inside the closure.
$foo = 42;
$bar = function () {
// can't access $foo in here
echo $foo; // undefined variable
};
$baz = function () use ($foo) {
// $foo is made available in here by use()
echo $foo; // 42
}
For example:
$array = array('foo', 'bar', 'baz');
$prefix = uniqid();
$array = array_map(function ($elem) use ($prefix) {
return $prefix . $elem;
}, $array);
// $array = array('4b3403665fea6foo', '4b3403665fea6bar', '4b3403665fea6baz');
Comments
It is telling the anonymous function to make $connections (a parent variable) available in its scope.
Without it, $connections wouldn't be defined inside the function.
1 Comment
Ian Gustafson
It should be noted that
$connections would not be null; it would be an undefined variable if it wasn't explicitly imported into the anonymous function's scope with use ($connections).Just an addition to the answer
$bok = fn() => "don't need to use $foo";
echo $bok(); // don't need to use 42
