Any way to check anonymous functions?

Question

Say that I have an array as follows:

array(
    [0] => function() { return "hello"; }
    [1] => function() { return "world"; }
    [2] => "look"
    [3] => function() { return "and";}
    [4] => function() { return "listen";}
)

Is there a way I can invoke 0, 1, 3 and 4 without invoking 2?

Answer 1

Anonymous functions are instances of the Closure class. So checking that and is_callable does the job.

foreach ($array as $func) {
    if (is_callable($func) && $func instanceof Closure) {
        $func();
    }
}

Actually, the class check should be enough since you cannot instantiate Closure objects manually except by creating an anonymous function.

Answer 2

I think this is what you want. $result will be an array of the return value of each function call (except if it's not an anonymous function, in which case it will be the original value from $array).

$result = array_map(
                    function($e) {
                      return ($e instanceof Closure && is_callable($e)) ?
                        $e() : $e;
                    }, $array);