That’s an interesting proposal. Here’s a link for reference:
https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160926/027287.html
<https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160926/027287.html>
The one thing is the proposed syntax doesn’t handle enum cases without
payloads. I think that could be handled by an optional Void, so this comment in
the original proposal:
> Only enum cases with a payload can be used with this syntax (it would make no
> sens for cases without a payload).
Would be changed to allow for empty payloads turning into Void?. For example:
> enum Result {
> case success(Int)
> case failure
> }
>
> let r: Result = foo()
>
> let x: Int? = r.success
> let y: Void? = r.failure
>
> assert(r.success == Optional(42))
> assert(r.failure == nil)
I think it’s a reasonable compromise, though I still think it’s a bit awkward
for the common case. Looks like this is being postponed for now, so we’ll have
to live with the alternatives.
Andy
> On Jan 18, 2017, at 12:20 AM, Anton Zhilin <[email protected]> wrote:
>
> AFAICS, Andy needs not default implementations of Equatable, but
> cases-as-optional-properties—this topic has also been discussed on the list.
>
> enum Result {
> case success(Int)
> case failure(String)
> }
>
> let r: Result = foo()
>
> let x: Int? = r.success
> let y: String? = r.failure
>
> assert(r.success == Optional(42))
> assert(r.failure == nil)
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