[swift-evolution] [pitch] Eliminate the "T1 -> T2" syntax, require "(T1) -> T2"
swift-evolution at haravikk.me
Fri Apr 15 08:26:24 CDT 2016
+1 to the proposal
> On 15 Apr 2016, at 13:11, David Hart via swift-evolution <swift-evolution at swift.org> wrote:
> If the original rationale is gone, shouldn’t we also get rid of the empty tuple-type and replace it by a full-blown Void instead of Void being a typealis for the empty tuple?
> (Int) -> Float
> (String) -> Void
> () -> Void
> () -> Double
> It looks more consistent to me.
Not sure about whether I’m a +1 to this; although I use Void everywhere already, I kind of get the rationale behind it being a zero element tuple, as single return types are basically one element tuples, and you can return tuples of any size you like.
Also, as an aside, I kind of liked that all functions took a tuple as their sole argument; I only use variadic parameters where they’re required for literal conformance (and I’ve no idea how else you’d handle that), but I suppose that ship has sailed.
>> On 15 Apr 2016, at 06:57, Chris Lattner via swift-evolution <swift-evolution at swift.org> wrote:
>> We currently accept function type syntax without parentheses, like:
>> Int -> Float
>> String -> ()
>> etc. The original rationale aligned with the fact that we wanted to treat all functions as taking a single parameter (which was often of tuple type) and producing a tuple value (which was sometimes a tuple, in the case of void and multiple return values). However, we’ve long since moved on from that early design point: there are a number of things that you can only do in a parameter list now (varargs, default args, etc), implicit tuple splat has been removed, and the compiler has long ago stopped modeling function parameters this way. Beyond that, it eliminates one potential style war.
>> Given all this, I think it makes sense to go for syntactic uniformity between parameter list and function types, and just require parenthesis on the argument list. The types above can be trivially written as:
>> (Int) -> Float
>> (String) -> ()
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