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

[Pierre Monod-Broca]

+1 for `type`, it is consistent with `func`, `var` and `init`. It looks good to me.

eg:

protocol Stream {
    type Payload
    var ready: Bool { get }
    func read() -> Payload?
}

protocol Collection {
    type Element
    var count: Int { get }
    func contains(element: Element) -> Bool
}


-- 
Pierre

> Le 19 déc. 2015 à 18:46, Loïc Lecrenier via swift-evolution <swift-evolution at swift.org> a écrit :
> 
> Hi,
> 
> I’m starting a new thread for this proposal https://github.com/apple/swift-evolution/blob/master/proposals/0011-replace-typealias-associated.md
> 
> So far, everybody agreed that using distinct keywords for type alias and associated type declarations is a good idea.
> However, some people think that “associated” is not an ideal replacement because it is too vague.
> I would like to choose a better keyword before the review, but I’m struggling to find a good replacement. 
> 
> So, here are some keywords that were proposed by the community.
> 
> 1. associated_type
> This is the original proposed keyword. It is extremely clear, but snake_cases are un-Swifty.
> 
> 2. associatedtype (or typeassociation)
> This was the first alternative to associated_type. Its purpose is still extremely clear.
> I like it a lot, but it is a bit long and difficult to read.
> 
> 3. associated
> This is the keyword I chose for the proposal because it was the most well-received initially. 
> It is quite short, very different from “typealias", and sounds good. However, it is also vaguer.
> Because the word “type” is not in it, it’s unclear what should follow it, and it’s unclear what it declares.
> For example, one could think that it is an associated *value* and write 
> protocol FixedSizeCollectionProtocol {
> 	associated size : Int
> }
> Although honestly I doubt many people would write that. 
> 
> 4. withtype (or needstype)
> It is short, somewhat easy to read, has the word “type” in it, and some concept of association thanks to “with”. I like it. 
> But it doesn’t sound very good, and is still vaguer than “associatedtype”.
> 
> 5. type
> This keyword was proposed by several people, but I strongly dislike it.
> It conflicts with an other proposal about unifying the “static” and “class” keywords for type-level members.
> I think the fact that it was proposed for two completely different purposes shows that it is too abstract.
> It would make searching for help more difficult because of its bad googleability.
> 
> 
> Personally, I would like to either keep “associated”, or use “associatedtype” because they are the most obvious choices.
> 
> 1) Do you agree about using “associatedtype”?
> 2) If not, which keyword would you prefer to use? why? (you can introduce a new one)
> Bonus) Maybe some twitter-famous person could make a quick poll and see which one developers prefer? 😁 (after they read this email)
> I would gladly do it myself, but I don’t think my twenty (mostly fake) followers will give me a lot of information.  
> 
> Loïc
> 
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