[swift-evolution] [Review] SE-0122: Use colons for subscript declarations

[Jaden Geller]

I’m +0.5 on this. I think it’s very natural to think of subscript as a parameterized property. I've felt like I’m doing mental gymnastics to reconcile the signature of the setter, and I think replacing `->` with `:` might actually make this easier to reason about.

I’m not sure why the style in the proposal differs from that that’s typical in Swift. Usually, there’s no space between the property name and the colon, a la: `subscript(index: Int): Element { … }`. I think the proposal should be updated to reflect typical Swift style unless it’s proposing a deviation here (which seems unlikely given the goal to unify the syntax with property syntax).

> On Jul 20, 2016, at 7:51 AM, Vladimir.S via swift-evolution <swift-evolution at swift.org> wrote:
> 
> +1 to clean up the syntax of subscripts. They acts as properties, not methods, so it is natural to express them with `:` and not with `->`.
> 
> Actually, I'd prefer additional change to use [] instead of () in declaration like:
> 
> subscript[externalName internalName: ParamType] : ElementType {
>    get { … }
>    set { … }
> }
> 
> especially if thinking about "Future directions" and confusion with parameterised accessor syntax(both declared with `()` but first used with `[]` and second with `()`).
> 
> On 20.07.2016 8:50, Chris Lattner via swift-evolution wrote:
>> Hello Swift community,
>> 
>> The review of "SE-0122: Use colons for subscript declarations " begins now and runs through July 24. The proposal is available here:
>> 
>> 	https://github.com/apple/swift-evolution/blob/master/proposals/0122-use-colons-for-subscript-type-declarations.md
>> 
>> Reviews are an important part of the Swift evolution process. All reviews should be sent to the swift-evolution mailing list at
>> 
>> 	https://lists.swift.org/mailman/listinfo/swift-evolution
>> 
>> or, if you would like to keep your feedback private, directly to the review manager.
>> 
>> What goes into a review?
>> 
>> The goal of the review process is to improve the proposal under review through constructive criticism and contribute to the direction of Swift. When writing your review, here are some questions you might want to answer in your review:
>> 
>> 	* What is your evaluation of the proposal?
>> 	* Is the problem being addressed significant enough to warrant a change to Swift?
>> 	* Does this proposal fit well with the feel and direction of Swift?
>> 	* If you have used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?
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>> 
>> More information about the Swift evolution process is available at
>> 
>> 	https://github.com/apple/swift-evolution/blob/master/process.md
>> 
>> Thank you,
>> 
>> -Chris Lattner
>> Review Manager
>> 
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