> Le 7 juin 2016 à 13:45, Charles Srstka via swift-evolution
> <[email protected]> a écrit :
>
>>> On Jun 7, 2016, at 11:47 AM, Brent Royal-Gordon via swift-evolution
>>> <[email protected]> wrote:
>>>
>>> I disagree. We are discussing how to annotate a function in some way so
>>> that the compiler knows that the code following it will never be executed
>>> *and* so a human who reads the declaration knows that it does not return.
>>> “Never" is a poor choice for that. Never what? Never return? Never use this
>>> function? Never say never again?
>>
>> "Never return". That's why it's in the return type slot, right after the
>> `->`. If you read it out loud, you'll read "returns Never", which is exactly
>> correct.
>>
>> NoReturn, on the other hand, does *not* read well in that slot: "returns
>> NoReturn". Huh? I mean, I suppose you won't misunderstand it, but it makes
>> no sense whatsoever *as a type name*.
>
> But it’s *not* a type. You’ll never have an instance of it. Since it’s not a
> type name, it doesn’t make sense that it needs to look like one. What it is
> doing is telling you something about the behavior of the function itself, not
> its return value. Its return value, if there were one, is irrelevant, since
> the function, by its very nature, will never even get to the point where it
> would return it. Either it’s going to kill the app via a fatalError or
> something, or we have something like dispatch_main() which will keep
> executing until the program stops, and one way or another, it won’t return.
>
> For that reason, frankly, I don’t understand why we want to change this from
> being an attribute, which seems to me the more natural and logical choice to
> describe this behavior. If we *do* have to change it, though, NoReturn
> conveys the most clearly to the reader what it does.
Not fully sure of the possibility and usefulness, but I think that moving from
the current attribute to a type could allow the registration of non returning
escaping closure.
I'll leave further investigation/discussion on the use of this '-> Never' with
closure to people using Swift on a daily basis, but something tell me it could
be handy.
Dany
_______________________________________________
swift-evolution mailing list
[email protected]
https://lists.swift.org/mailman/listinfo/swift-evolution
