Re: Inconsistencies in callable, call_user_func and direct variable calls

Sebastian B.-Hagensen wrote on 19/03/2015 16:27:

Another way to unify array and string callback may be to use the callable syntax and have it return a closure: callable('strlen'); callable($object, $methodName); callable('class', 'staticMethod')

Andrea proposed a slightly different syntax for function references a few months back - see withdrawn RFC [1] and accompanying Internals thread [2]. I actually quite like the callable() syntax. Whereas Andrea's suggestion was a parser rule that took a bare string, like &foo, this would have to always take a string, like callable('foo'), but that's good if we want to roll in dynamic callbacks as well: Right now, we have to embed the type information in the variable name, because this is just a string: $hook_callback = 'hook_' . $hook_name; This has a much strong information scent: $hook = callable('hook_' . $hook_name); There's then the question of what kind of object it would return - a Closure? Some child or sibling of Closure? What methods could be usefully provided? What should happen if the arguments provided aren't callable? Throw an exception? Also, do we still need a way to delay testing of callability, to allow this: class A {

    private function foo() { echo 'foo'; }
    public function bar(callable $call) { $call(); }

} $a = new A; // A::foo is not callable here, but will be when we get inside A::bar var_dump(is_callable([$a, 'foo'] )); $a->bar( [$a, 'foo'] ); Currently works: http://3v4l.org/pNZgn [1] https://wiki.php.net/rfc/function_referencing [2] http://marc.info/?t=140710275400001&r=2&w=2 Regards, -- Rowan Collins [IMSoP]