[swift-evolution] [draft] Compound Names For Enum Cases

[Christopher Kornher]

Your example is only has only one case, which is not typical. Perhaps I am missing something, but the only reason that I can imagine for having a case with multiple ways to “construct” it is to have all variants of the case to match. If you don’t want them to match, use a different case name. 

It would still be possible to match on the different types of bar when needed:

```
enum Foo {
    case bar(a: Int)
    case bar(b: String)
    case notAbar
}


 switch aFoo {
    case .bar( let a: Int) : // matches Ints only 
	...

    case .bar( let b: String) : // matches Strings only
       ...
}

switch aFoo {
    case .bar :  // Matches both  cases and that is a good thing
	…

    case notAbar:
	….
}

```

> On Jan 24, 2017, at 5:27 AM, Xiaodi Wu via swift-evolution <swift-evolution at swift.org> wrote:
> 
> I would imagine it would be logical to have it work just like it does now with functions. If case bar is distinct, then that should still work, but if bar is "overloaded," then case bar should be invalid for ambiguity. Seems fine to me, shouldn't break any existing code and therefore we don't lose anything.
> 
> 
> On Tue, Jan 24, 2017 at 01:13 David Hart via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
> 
> 
> On 24 Jan 2017, at 00:52, Joe Groff via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
> 
>> We're not terribly principled about this right now with non-pattern declaration references. You can still reference an unapplied function by its base name alone without its labels, if it's unambiguous:
>> 
>> func foo(x: Int, y: Int) {}
>> 
>> let foo_x_y: (Int, Int) -> () = foo
>> 
>> so it'd be consistent to continue to allow the same in pattern references.
> 
> WRT ambiguity, do we loose the ability to pattern match on the naked case name when two cases share the same base name?
> 
> enum Foo {
>     case bar(a: Int)
>     case bar(b: String)
> }
> 
> switch aFoo {
>     case .bar: // matches both cases
>         break
> }
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