One argument against `?? () -> Never` is that `func f() -> Never { while true
{} }` will also work.
Max
> On Jun 28, 2017, at 8:35 AM, Ben Cohen <[email protected]> wrote:
>
>
>> On Jun 28, 2017, at 6:03 AM, Erica Sadun via swift-evolution
>> <[email protected] <mailto:[email protected]>> wrote:
>>
>> In general, does everyone prefer `?? () -> Never` or `!! () -> Never`? I can
>> argue both ways, with the goal in reading code as "unwrap or die".
>>
>
>
> Personally, I strongly prefer `foo !! "explanation"` over `foo ??
> fatalError()`. I don’t think adding another operator for what is a very
> common need is a concern, and is easier to read at a glance than the
> ??/fatalError combo. There is a bit of cognitive dissonance between ??, a
> normally-fluffy nonthreatening defaulting operator, and fatalError, a scary
> beware operator. `!!` OTOH matches `!` in clearly flagging the unwrap as
> unsafe and that your program will exit. I also think it would be easier to
> explain `!!` to beginners as part of a wider story explaining optionals in
> general, unwraps, what `nil` means and what `!` means etc. Whereas `foo ??
> Never` requires a lot of heavy lifting to understand how/why it works – we
> might all understand it, but that understanding is built on a lot of
> foundational understanding.
>
> I also think a `Never` type would be very useful. Just that for this
> particular case, `!!` is still worth adding too.
>
>
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