Dmitry Stogov wrote on 19/04/2016 15:48:
callable-type is much simpler solution for this use-case.
Usage of Interfaces to check function prototypes is a bit tricky, but
yes, this is a possible use-case.
Do you like to work with framework, that use this trick for every
callback?
If you don't use __invoke as the function name, you can have a single
class implement multiple contracts, e.g. to register for more than one
event type with different signatures.
I guess if you had callable-types *and* union types, you could get the
best of both worlds:
interface UserEventCallbackInterface {
public function handleUserEvent(UserEvent $event): boolean;
}
public function registerCallback(EventCallbackInterface|callable(Event):
boolean $handler) { ... }
The implementation has to be a bit fiddlier here, because you need to
sometimes call $handler->handleUserEvent($event) and sometimes
$handler($event); with a functional interface, the engine makes
$handler->handleUserEvent($event) work for you. The cost is that the
call site has to be a bit more verbose to specify the interface, rather
than implicitly meeting the contract.
Regards,
--
Rowan Collins
[IMSoP]
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