CODEWITHSUNDEEP
phpclosures
gremo
gremo

Reputation: 48919

PHP closure as an optional function argument

Would be possible to specify a default argument value when argument is a PHP closure? Like:

public function getCollection($filter = function($e) { return $e; })
{
    // Stuff
}

Am i missing something (maybe a different syntax?) or it's not possible at all? Of course i know i can do:

public function getCollection($filter = null)
{
    $filter = is_callable($filter) ? $filter : function($e) { return $e; };
    // Stuff
}

(NOTE: I didn't test the above code)

Upvotes: 16

Views: 2856

Answers (2)

Numid
Numid

Reputation: 551

What about the following?

public function getCollection(?Closure $filter = null)
{
     $filter ??= fn($e) => $e;
     // Stuff
}

Upvotes: 0

gen_Eric
gen_Eric

Reputation: 227280

Default arguments can only be "scalar arguments", arrays, or NULL.

"scalar values" in PHP are numbers, strings, and booleans.

If you want a function to be a default argument, you're gonna need to use the 2nd way, the 1st is a syntax error.

Upvotes: 18

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