On 24/04/2017 10:42, Jonathan Hull wrote:
You can also do:switch self { case .Int: return "int" case .Fun(.Fun(let p), let r): return "(\(p)) -> \(r)" case .Fun(let p, let r): return "(\(p) -> \(r))" }
I didn't know you can do that and it seems consistent with other features of the language. However, it doesn't do what I was aiming for. In your example `p` will be bound to a `(Type, Type)`, not a `Type`. So the string result, instead of being `(int -> int) -> int` is actually `((int, int)) -> int`.
Anyway, I've learned something new, so thanks!
On Apr 23, 2017, at 6:55 AM, Ionuț G. Stan via swift-evolution <[email protected]> wrote: Hi all, I'm unsure if this is the appropriate venue to discuss this, so apologies if it's not. I was wondering if the issue of supporting as-patterns in switch statements has been brought up before or not, and what was the outcome of that. By as-patterns I mean the ability to bind sub-patterns to identifiers. See this question of mine on StackOverflow for an example: http://stackoverflow.com/questions/43566117/haskell-like-as-patterns-in-swift/43567041#43567041 Maybe an equal sign could be used to denote that, so my example above would become: switch self { case .Int: return "int" case .Fun(let p = .Fun, let r): return "(\(p)) -> \(r)" case .Fun(let p, let r): return "(\(p) -> \(r))" } Note the `let p = .Fun` part. Alternatively, enhancing the `where` clause of a `case` to support the same features as an `if case` expression, would be an acceptable choice, too? case .Fun(let p, let r) where case .Fun = p: return "(\(p)) -> \(r)" Thanks for reading. -- Ionuț G. Stan | http://igstan.ro | http://bucharestfp.ro _______________________________________________ swift-evolution mailing list [email protected] https://lists.swift.org/mailman/listinfo/swift-evolution
-- Ionuț G. Stan | http://igstan.ro | http://bucharestfp.ro _______________________________________________ swift-evolution mailing list [email protected] https://lists.swift.org/mailman/listinfo/swift-evolution
