[swift-evolution] [Review] SE-0073: Marking closures as executing exactly once

[Dave Abrahams]

on Tue May 03 2016, Chris Lattner <swift-evolution at swift.org> wrote:

> Hello Swift community,
>
> The review of "SE-0073: Marking closures as executing exactly once"
> begins now and runs through May 9. The proposal is available here:
>
> 	https://github.com/apple/swift-evolution/blob/master/proposals/0073-noescape-once.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?

I think it's of questionable importance and doesn't generalize well.
For example, you can't use this to construct something like 

  var x: Int
  functionThatActsLikeIf( someTest(), then: { x = 1 }, else: { x = 2} )

If you need to initialize something in an outer scope with something
computed by a closure, it's much better to arrange something like this:
    
  var x = functionThatActsLikeIf( someTest(), then: {  1 }, else: { 2 } )

-- 
Dave