[swift-evolution] Remove forEach?

[J. Cheyo Jimenez]

Could such construct also allow for an if-else expression like behavior?

let result = if bool { 1 } else { 2 }

 Or would this be better modeled as a non block-like expression?

let result = 1 if bool else 2

I'm just curious, this maybe be out of topic/ unrelated.


On Wednesday, December 9, 2015, Joe Groff via swift-evolution <
swift-evolution at swift.org> wrote:

>
> On Dec 9, 2015, at 8:47 AM, David Owens II <david at owensd.io
> <javascript:_e(%7B%7D,'cvml','david at owensd.io');>> wrote:
>
> Another language construct seems a bit much for this, right? Maybe I’m
> missing something, but can’t we get the same behavior with an overload?
>
>
> A language construct that helps eliminate multiple other language
> constructs would potentially be a net win, though. If there were closures
> that supported nonlocal exits, then `do`, `for...in`, and possibly other
> constructs could become library functions, and other "block-like" library
> features like `autoreleasepool`, `withUnsafePointer` would work more
> naturally too.
>
> -Joe
>
> extension Array {
>     func forEach<U>(body: (element: Element) throws -> U?) rethrows -> U? {
>         for e in self {
>             if let result = try body(element: e) { return result }
>         }
>
>         return nil
>     }
> }
>
> func g(e: Int) -> Int? {
>     if e == 2 { return e }
>     return nil
> }
>
> let arr = [1, 2, 3]
> arr.forEach { print($0) }
> let result = arr.forEach(g)
> result                           // has the value of 2
>
>
>
> Now, Swift has some issues determining the types properly if you attempt
> to inline the g function at the forEach() callsite, but that can be fixed.
>
> -David
>
> On Dec 9, 2015, at 4:40 AM, Stephen Celis via swift-evolution <
> swift-evolution at swift.org
> <javascript:_e(%7B%7D,'cvml','swift-evolution at swift.org');>> wrote:
>
> On Dec 8, 2015, at 5:13 PM, Joe Groff via swift-evolution <
> swift-evolution at swift.org
> <javascript:_e(%7B%7D,'cvml','swift-evolution at swift.org');>> wrote:
>
> Another direction you might take this is to make it a type annotation on
> the function type, like throws, so forEach has a type like this:
>
> func forEach(body: (Element) breaks -> ())
>
> and a closure that `breaks` has nonlocal behavior for
> break/continue/return (and is implied to be noescape and void-returning, I
> guess).
>
>
> This is really interesting. Ruby provides similar functionality with its
> lambda vs. proc, but a type annotation is much more understandable. It
> could also imply @noescape automatically:
>
>    func forEach(@canbreak body: Element -> Void)
>
> Stephen
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>
>
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