Question

I’m trying to store anonymous functions in a static array property of my class. These functions should be invoked later by their index, but calling

self::$arr['index']()

just doesn’t work, while

$a = self::$arr['index'];
$a();

does!

This doesn’t work:

class A {
    private static $func = array('a' => '');
    public function __construct() {
        self::$func['a'] = create_function('$str', 'echo "$str";');
    }
    public function go($str) {
        self::$func['a']($str);  // Call the function directly
    }
}
$a = new A();
$a->go("hooray");  // Outputs "Undefined variable: func"

But this does:

class A {
    private static $func = array('a' => '');
    public function __construct() {
        self::$func['a'] = create_function('$str', 'echo "$str";');
    }
    public function go($str) {
        $a = self::$func['a'];  // Pass the function name to a variable
        $a($str);               // Call the function via the variable
    }
}
$a = new A();
$a->go("hooray");  // Outputs "hooray"

Why?

I’m using PHP Version 5.4.3

Answer 1

this is the behavior of php’s parser

$functionName['a'] = "hello";
self::$functionName['a']();

calls

self::hello();

… the very sad thing is that in php you can’t do this:

(self::$functionName['a'])(); // doesn't work in php :(

as you can do in javascript, for example

what you can do is… use a temporary variable like you said

$a = self::$func['a'];
$a($parameter);

or

call_user_func(self::$func['a'], $parameter);

hope this helps…

---

in latest phps these features were added

$a['sss'] = function(){ echo 'bla'; };
$a['sss']();

class Bla
{
    private $a;
    function test()
    {
        $this->a['sss'] = function(){ echo 'bla2'; };
        $this->a['sss']();
    }
}
$c = new Bla();
$c->test();

and they work properly… so for some reason, this syntax doesn’t work only when using the scope resolution operator ( ClassName:: self:: etc)