[swift-evolution] [Idea] Custom default names for arguments of closures

[Howard Lovatt]

Sorry, not keen. Too much overlap with labels, therefore not worth the
addition.

  -- Howard.

On 14 February 2016 at 07:38, Eugene Gubin via swift-evolution <
swift-evolution at swift.org> wrote:

> Right now Swift provides shorthand argument names ($0, $1 etc) by default
> which could be overriden with more specific names. I think it would be nice
> to define our own default names as part of type definition:
>
> typealias Closure = (first one: String, second two: String) -> Void
>
> func executeClosure(closure: Closure) {
> // the caller uses external parameter names, nothing changed here
> closure(first: "first", second: 2)
> }
>
> executeClosure {
> // the callee uses custom arguments instead of $0, $1
> // also it is possible to override these names here as usual
> print("one \(one) two \(two)")
> }
>
> This feature is backward compatible in that way what both
>
> typealias Closure = (first: String, second: String) -> Void
>
> and
>
> typealias Closure = (String, String) -> Void
>
> will provide the same behavior like now.
>
> Possible applications: providing default argument names more meaningfull
> than $0, $1, DSL-like constructions.
>
> Possible problem: names could overlap. Nothing new. $0, $1 could overlap
> too. Override argument names or variable names in a scope.
>
> _______________________________________________
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> swift-evolution at swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution
>
>
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