On Thu, Apr 20, 2023, at 8:26 PM, Michał Marcin Brzuchalski wrote:
> Hi
>
>> There is one loophole, in that an interface may require an __invoke()
>> method:
>>
>> interface TwoInts
>> {
>> public function __invoke(int $a, int $b): int;
>> }
>>
>>
> I was playing around with the code and parser for this in 2020 but my idea
> was to introduce a new syntax that is inspired by C# - Delegates [1]
>
> delegate Reducer (?int $sum, int $item = 0): int;
>
> class Foo implements Reducer {
> public function __invoke(?int $sum, int $item = 0): int { }
> }
> function reduce(Reducer $reducer) {
> var_dump($reducer(0, 5));
> }
> reduce(new Foo());
> reduce(fn(?int $sum, int $item = 0): int => 8);
>
> At the same time, I assumed structural typing for closures would be used.
> I assumed the delegate will resolve into
> interface Reducer {
> public function __invoke(?int $sum, int $item = 0): int {}
> }
This is effectively the same as the "typedef" version of callable types from my
email to Dan a moment ago. See there for the challenges.
--Larry Garfield
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