[swift-evolution] Optionals and nil in Switch statement

[Nevin Brackett-Rozinsky]

Does `case "text"?` work?


On Tuesday, June 28, 2016, Kevin Nattinger via swift-evolution <
swift-evolution at swift.org> wrote:

> Case .none:
> Case .some("string"):
>
>
> On Jun 28, 2016, at 06:40, Lucas Jordan via swift-evolution <
> swift-evolution at swift.org
> <javascript:_e(%7B%7D,'cvml','swift-evolution at swift.org');>> wrote:
>
> Forgive me if this was/is discussed already, I am new to the process
> here....
>
> (code is attached as a playground too)
>
>
>
> Sometimes when I am working with a String? nil can be a reasonable value,
> and what I want to do is something like the following:
>
> import UIKit
>
>
> var str:String? = "Hello, playground"
>
>
> switch str{
>
> case nil:
>
>     print("Nil!")
>
> case "Hello, playground":  //it would be super nice if this worked.
>
>     print("Match")
>
> default:
>
>     print("Some other non nil value?")
>
> }
>
>
> But it does not work, the orange  text is a compile time error,
> "Expression pattern of type 'String' cannot match value of type 'String?'.
> I realize that this can be replaced with a let statement (case let s where
> s == "Hello, playground":), but that is verbose.
>
> Seems like the compiler could be OK with the orange text, since it is
> clearly not nil.
>
> Thoughts?
>
> -Lucas
>
>
>
>
>
> <NilInSwitchStatements.playground.zip>
>
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