On Apr 26, 2016, at 10:52 AM, Mishal Awadah via swift-evolution <swift-evolution@swift.org> wrote: > Concern 1: > I feel like we're forgetting about the functional programming syntax of > declaring function types like this: > > A -> B -> C > > for a function foo(a: A, b: B) -> C
This analogy doesn’t exist in Swift, languages like Haskell have auto-currying behavior like this, but Swift does not. > > This eliminates the ambiguity of what the parameter types are, and is more > legible (less paren hell) than adding parens like this: > > (A,B) -> C > > which for a function > > foo(a: (A, B)) -> C > > would look like this after the implementation of SE-0066: > > ((A,B)) -> C > > instead of > > (A,B) -> C I’m not sure what the actual concern you’re pointing out here. However, you are forgetting the argument labels. Your foo example will have type: (a: (A,B)) -> C More to the point thought, this example is *exactly* why SE-0066 is the right thing to do. You cannot currently write the type of “foo” as "(A,B) -> C”. (with or without labels), because of the grammar ambiguities that SE-0066 fixes. That said, it is likely that I’m totally missing your point here, can you please restate your concern? > Concern 2: > > There's also the potential to transform a function like this > > A -> B -> C > > into this > > B -> C > > after partial application, something which might not be totally irrelevant to > Swift in its future. This isn’t affected by SE-0066 - what is your concern? With SE-0066, the transformation is: (A) -> (B) -> C into: (B) -> C Please keep in mind that SE-0066 doesn’t change the type system, it just adds parens in a very narrow case. > > > Here are a few contrived examples of function types showing the paren version > (order 66), the parens on the return type too, and the generic functional > programming version (right). I want to preface this with, "Remember that > Swift is an enjoyable experience because reading Swift is pleasant.” 0066 does not affect the return type of a function. -Chris _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution
