Corrections, additions below…
> Let's consider the following declarations:
>
> class Bar {
> func baz() // #8 Method named 'Bar.baz(_)' with
> type 'Bar -> () -> ()'.
> func baz(x y: Int) // #9 Method named 'Bar.baz(x:)' with
> type 'Bar -> Int -> ()'.
> static func baz(x: Int = 0) // #10 Static method named
> 'Bar.Self.baz(x:)' with type 'Int -> ()'.
> }
> // ...
> let bar = Bar()
> let f10 = bar.baz // error: not a function reference, did
> you mean 'bar.baz(_)' or 'bar.baz(x:)'?
> let f11 = bar.baz(_) // #18 Function synonymous to the
> closure '{ bar.baz() }' with type '() -> ()'.
> let f12 = bar.baz(x:) // #19 Function synonymous to the
> closure '{ bar.baz(x: $0) }' with type 'Int -> ()'.
> let f13 = Bar.Self.baz(x:) // #20 Function synonymous to the
> closure '{ Bar.baz(x: $0) }' with type 'Int -> ()'.
> let f14 = Bar.Self.baz(_) // #21 Function synonymous to the
> closure '{ Bar.baz() }' with type '() -> ()'.
(…)
> C2: Extend SE-0021
> <https://github.com/apple/swift-evolution/blob/master/proposals/0021-generalized-naming.md>
> by removing the ambiguity between instance and type members. From now on,
> `Bar.baz(_)`
That was meant to read:
"(…) From now on, `Bar.baz(_)` unambiguously refers to the instance method
named `baz(_)`. To refer to the static or class method named `baz(_)`, put the
keyword `.Self` between the type and the base name. This syntax should align
with the outcome of SE-0068
<https://github.com/apple/swift-evolution/blob/master/proposals/0068-universal-self.md>
such the keyword resembles the static method call `thing.Self.baz()` of a
`thing` of type `Bar`."
(Alternatives considered: (1) the use of `Bar.self.baz(_)` with lower-case
`self`, which is probably more confusing; and (2) inverting the choice and
making the instance method require a keyword instead, which would harm
readability as it's usually the instance method that you'd refer to and not the
static one.)
> C6: Clarify that by using the base name `foo` for a function, the same scope
> cannot define a variable with the name `foo`. And, vice versa, in a scope
> that defines a variable named `foo`, there can be no function `foo(...)`
> defined at the same scope level.
This doesn't prevent shadowing of course. E.g. An inner scope with a variable
named `foo` would shadow all functions named `foo(...)` of an enclosing scope.
> The implications are:
>
> I1: The use of a function's base name to refer to a function will cease to
> work. It has, however, been buggy up to this date. Consider the following:
>
> let f = [Int].prefix // '[Int] -> Int -> ArraySlice<Int>'
>
> let g1 = [Int].dropFirst // Inexplicably chooses the '[Int] -> Int ->
> ArraySlice<Int>' overload!
> let g2 = [Int].dropFirst as [Int] -> () -> ArraySlice<Int> //
> Disambiguate by type.
>
> let h1 = [Int].sorted // Chooses the '[Int] -> () -> [Int]' overload,
> unlike 'dropFirst' above.
> let h2 = [Int].sorted as [Int] -> ((Int, Int) -> Bool) -> [Int] //
> Disambiguate by type.
By the way, the same also happens with the current Swift (both 2.2 and 3
master) when referring to the partially applied instance method like so:
let xs = [1,3,2]
let g = xs.dropFirst // Chooses the 'Int -> ArraySlice<Int>' overload.
let h = xs.sorted // Chooses the '() -> [Int]' overload, unlike
'dropFirst' above.
> I3: Function argument lists are no longer that special and there's no need to
> notate single-n-tuple argument lists separately from n-argument functions,
> i.e. SE-0066
> <https://github.com/apple/swift-evolution/blob/master/proposals/0066-standardize-function-type-syntax.md>
> is not really needed anymore. The new intuition here is that it's the
> function's name that defines how a function can be called, not its type.
In yet other words, we don't have to capture the arity of a function in the
type system at all—it's enough to carry that information around in the function
name.
~>
Finally, this was a fairly technical pitch but a pitch anyway. Any ideas pro or
against?
— Pyry
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