[swift-evolution] [SE-0011] Re-considering the replacement keyword for "typealias"

Dave Abrahams dabrahams at apple.com
Sat Dec 19 14:54:13 CST 2015

> On Dec 19, 2015, at 12:17 PM, Michael Henson via swift-evolution <swift-evolution at swift.org> wrote:
> 1) Do you agree about using “associatedtype”?
> 2) If not, which keyword would you prefer to use? why? (you can introduce a new one)
> There is another alternative. Rather than trying to come up with another brand-new keyword, we can re-use one that has an existing and appropriate meaning: required.
> Example:
> protocol ExampleProtocol {
>   required typealias Element
>   typealias MethodSignature = (arg: Element) -> Bool
>   ... etc
> }
> It's a little more verbose at the point of use but the declarations are relatively uncommon and this usage is clearly separate from regular typealias declarations.

I think this is a big improvement over associatedtype, except that the type that satisfies the requirement needn't be a typealias.  I would therefore prefer "requiredtype."


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