[swift-evolution] Normalizing operator's types

[David Sweeris]

Function currying wasn’t removed, just some of the confusing syntax for it. This works fine in the Xcode 8 beta:
infix operator <> {} // random operator that doesn’t do anything else
func <> <T, U, V> (op: (T, U) -> V, rhs: U) -> ((T) -> V) { return { op($0, rhs) } }
func <> <T, U, V> (lhs: T, op: (T, U) -> V) -> ((U) -> V) { return { op(lhs, $0) } }
let divby2 = (/) <> 2
print(divby2(10)) // prints "5"
let invert = 1.0 <> (/)
print(invert(10)) // prints "0.1"



More to the point, though, given this definition:
let foo: (Int) -> (Int) -> (Int)
Would the correct way to use `foo` with today’s syntax be "foo(Int) -> (Int, Int)”, "foo(Int) -> ((Int) -> Int)”, or "foo(Int, Int) -> Int”?

Seems like a lot of confusion and ambiguity for something that, at least as far as I can tell, doesn’t actually provide any functionality.

- Dave Sweeris

> On Jun 15, 2016, at 2:07 PM, J. Charles N. MBIADA via swift-evolution <swift-evolution at swift.org> wrote:
> 
> Hi Swift,
> 
> Since the "removal" of curried function, I am looking for some elegant ways to work with partial functions (and reduce creation of closure and nested func for the developper).
> 
> And now I am asking myself if it's not better to align operator's types to the arrow style instead of using tuple argument style.
> 
> For example: 
> Why Int.multiplyWithOverflow's type is (Int, Int) -> (Int, overflow: Bool) instead of (Int -> Int) -> (Int, overflow: Bool)
> 
> When curried function will come back (if it come back, which is a personal hope) that will avoid many refactoring.
> 
> I think that, write this : let f:(Int, Int) throws -> Int = (+) seem a bit ugly for this purpose 
> let f:(Int -> Int) -> Int = (+) seem more suitable.
> 
> We could imagine that in the future the compile could automatically create a closure if the programmer define something like
> 
> let lmul: (Int) -> (Int) -> (Int) = (*)
> 
> and then, doing the habitual stuffs : let mulOfTwo = lmul(2)
> 
> 
> Kind regards,
> --
> jcnm
> _______________________________________________
> swift-evolution mailing list
> swift-evolution at swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-evolution/attachments/20160615/7f710004/attachment.html>