[swift-evolution] [Idea] Find alternatives to `switch self`

[Charles Constant]

I wrote some code tonight to experiment with this kind of thing. I
apologize if it's off-topic for the thread, but it might be useful to
others who want to experiment.



//: Playground - noun: a place where people can play


import Cocoa


infix operator • { precedence 180 }

infix operator → { associativity left precedence 70 }

infix operator … { associativity right precedence 60 }


func → <T>( lhs: Bool, rhs: T ) -> T? {

return lhs ? rhs : nil

}


func … <T>( lhs:T?, rhs:T ) -> T {

return lhs != nil ? lhs! : rhs

}


func depends<I,O>( dep:I, _ closure: (I)->(O) ) -> O {

return closure( dep )

}


func • <I,O>( lhs: I, rhs: (I)->(O) ) -> O {

return depends( lhs, rhs )

}


/* Example using "depends" */


let

str:String,

i = 7


str = depends( i ){

$0==2 → "two" …

$0==3 → "three" …

$0==4 → "four" …

"other"

}


/* Example using "•" operator as "depends" */


enum People { case Kurtz, Popescu, Lime, Martins }

enum Order { case First, Second, Third, Unknown }


let

order:Order,

person:People = .Lime


order = person • {

$0 == .Kurtz → .First …

$0 == .Popescu → .Second …

$0 == .Lime → .Third …

.Unknown

}



I also have some trepidation about posting it here, because it might have
bugs. I wans't sure what "precedence" and "associativity" should be, for
example. But it does make it more convenient to test alternative characters
for operators, etc.











On Sat, Apr 9, 2016 at 12:05 AM, Vladimir.S via swift-evolution <
swift-evolution at swift.org> wrote:

>
> On 09.04.2016 9:31, Brent Royal-Gordon wrote:
>
>> This design is still very much under development—it hasn't even been
>> reviewed, let alone added to the language. Here's the draft proposal:<
>> https://github.com/jtbandes/swift-evolution/blob/case-enumerable/proposals/0000-derived-collection-of-enum-cases.md
>> >
>>
>> I'm not saying that this will necessarily be a solution that ends up
>> being accepted—I'm merely saying that yes, it's something people are
>> thinking about and designing; it's just been inactive for a few weeks.
>>
>
> Oh, I see. Thank you for letting know. Just missed "you would be able" in
> your previous message, did read it as "you are able", so was trying to find
> this in current Swift version. OK, glad to know that most likely we'll have
> improvements in enums eterations for Swift 3.0.
>
> _______________________________________________
> swift-evolution mailing list
> swift-evolution at swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution
>
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