What is your evaluation of the proposal?
I reluctantly agree with the proposal with the following caveat: I do not agree
with the rationale to support being able to choose to omit the () for the
parameter list of the closure declaration.
I see no cohesive argument that says that the parens should be required in some
cases but not in others when talking about parameter lists.
I believe the proposal should be amended that the following should be the only
allowable forms:
y = x.sorted { (lhs : Int, rhs : Int) -> Bool in rhs < lhs }
y = x.sorted { (lhs, rhs) in rhs < lhs }
y = x.sorted { $1 < $0 }
I’ve bolded the change above, today this is allowable:
y = x.sorted { lhs, rhs in rhs < lhs }
I’ve read the argument about why it’s ok to elide the parens here, I simply
disagree with the author’s premise that this is a structurally significant
different form. Not requiring the parens for this parameter list begs the
question why other forms require them and provides a similar ambiguity of
whether the closure takes two parameters or a single tuple parameter from both
of these valid syntaxes today:
y = x.sorted { lhs, rhs in rhs < lhs }
y = x.sorted { (lhs, rhs) in rhs < lhs }
I don’t see how this is fundamentally different than the example in the
“Motivation” section:
(Int, Float) -> Int // Takes two arguments, or takes one two-argument tuple?
While I will concede that `(lhs, rhs)` is not a valid tuple declaration, I’d
still argue that it’s too subtle of a difference to be used a primary means of
justification. If we are going to remove the ambiguity, let’s remove it for all
parameter list scenarios.
Is the problem being addressed significant enough to warrant a change to Swift?
Potentially.
Does this proposal fit well with the feel and direction of Swift?
Yes.
How much effort did you put into your review? A glance, a quick reading, or an
in-depth study?
I participated in the original discussion thread as well as tested out many
different combinations function and closure syntax in the Swift Playground.
-David
> On Apr 25, 2016, at 9:22 PM, Douglas Gregor via swift-evolution
> <[email protected]> wrote:
>
> Hello Swift community,
>
> The review of SE-0066 "Standardize function type argument syntax to require
> parentheses" begins now and runs through May 2, 2016. The proposal is
> available here:
>
> https://github.com/apple/swift-evolution/blob/master/proposals/0066-standardize-function-type-syntax.md
>
> <https://github.com/apple/swift-evolution/blob/master/proposals/0066-standardize-function-type-syntax.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
> <https://lists.swift.org/mailman/listinfo/swift-evolution>
> or, if you would like to keep your feedback private, directly to the review
> manager. When replying, please try to keep the proposal link at the top of
> the message:
>
> Proposal link:
>
> https://github.com/apple/swift-evolution/blob/master/proposals/0066-standardize-function-type-syntax.md
>
> <https://github.com/apple/swift-evolution/blob/master/proposals/0066-standardize-function-type-syntax.md>
> Reply text
>
> Other replies
> <https://github.com/apple/swift-evolution#what-goes-into-a-review-1>What
> goes into a review?
>
> The goal of the review process is to improve the proposal under review
> through constructive criticism and, eventually, determine 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?
> How much effort did you put into your review? A glance, a quick reading, or
> an in-depth study?
> More information about the Swift evolution process is available at
>
> https://github.com/apple/swift-evolution/blob/master/process.md
> <https://github.com/apple/swift-evolution/blob/master/process.md>
> Thank you,
>
> Doug Gregor
>
> Review Manager
>
>
> _______________________________________________
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