> On Jan 8, 2017, at 06:53, Karim Nassar via swift-evolution
> <[email protected]> wrote:
>
> One area of enums that I’d love to see some sugar wrapped around (and perhaps
> this has already been discussed previously?) is extracting associated values.
>
> There are many times where, given an enum like:
>
> enum Feedback {
> case ok
> case info(String)
> case warning(String, Location)
> case error(String, Location)
> }
>
> I’d love it if we could tag the associated values with some semantic
> accessor, perhaps borrowed from tuples:
>
> enum Feedback {
> case ok
> case info(msg: String)
> case warning(msg: String, loc: Location)
> case error(msg: String, loc: Location)
> }
>
> then:
>
> let foo = self.getSomeFeedback() // -> Feedback
> if let msg = foo.msg { // since not all cases can hold a ‘msg’ .msg is an
> Optional
> print(foo)
> }
Can't remember if it's come up before, but +1. I can't count how many times
I've written something like:
enum Foo : CustomStringConvertible {
case c1(T1)
case c2(T2)
...
case cN(TN)
var description: String {
switch self {
case .c1(let val): return "\(val)"
case .c2(let val): return "\(val)"
...
case .cN(let val): return "\(val)"
}
}
}
Being able to simplify that to:
var description: String {
let nilDesc = "some appropriate description"
return "\(self.0 ?? nilDesc)"
}
Would be great.
- Dave Sweeris _______________________________________________
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