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

[James Campbell]

If part of this proposal is to update documentation to refer to it as
"placeholder" typed then I am okay with "type"

On Wed, Dec 23, 2015 at 1:15 PM, Craig Cruden <ccruden at novafore.com> wrote:

> I prefer “type”.
>
>
> On 2015-12-23, at 20:05:46, Pierre Monod-Broca via swift-evolution <
> swift-evolution at swift.org> wrote:
>
> I would agree to stop talking about associated types and start talking
> about placeholder types instead.
> But as a keyword, IMO the problem is that `placeholder` is not appropriate
> to define the implementation.
>
> eg
> class Foo: Stream {
>     placeholder Payload = String // IMO doesn't feel right
>     type Payload = String // IMO feels good
> }
>
> --
> Pierre
>
> Le 23 déc. 2015 à 13:59, James Campbell <james at supmenow.com> a écrit :
>
> I think we should use "placeholder" it more accurately describes what it
> does. For a bigger change then I would propose my protocol generics idea.
>
> On Wed, Dec 23, 2015 at 12:50 PM, Pierre Monod-Broca via swift-evolution <
> swift-evolution at swift.org> wrote:
>
>> +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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>>
>>
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>>
>
>
> --
>  Wizard
> james at supmenow.com
> +44 7523 279 698
>
>
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>


-- 
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