[swift-evolution] repeat loop enhancement

[Kevin Kachikian]

I like it!

Anything to keep heading down the cleaner syntax path as Swift cleans up so much of the visual noise that ObjC used to present.

That said, with. map and other capabilities, how often would this be used?


> On Dec 8, 2015, at 1:54 PM, Jason Pollack via swift-evolution <swift-evolution at swift.org> wrote:
> 
> I'd like to propose a small enhancement to the repeat loop.
> 
> Currently if we want to perform 'count' iterations in a loop, we need to do something like:
> 
> for _ in 0 ..< count {
>    //Do something here
> }
> 
> It looks and feels a little awkward. We need to create an unnamed variable, and it's easy to forget (especially for language newcomers) that the loop starts with 0 and doesn't include count.
> 
> We can also do:
> 
> var i = 0
> repeat {
>     //Some code
>     i += 1
> } while i < 10
> 
> This is worse, in that it introduces a variable in the outer scope, and puts the repeat count at the end. Plus, if the expression inside the repeat is complex, the value of i may never be incremented, or may be incremented more than once.
> 
> 
> I propose the following:
> 
> repeat count {
>     //Do something here
> }
> 
> It's cleaner, and IMO clearer what this code is intended to do.
> 
> Naturally 'count' should be non-negative. A while clause is not needed, although I could imagine it being supplied, to create a construct such as:
> 
> var ok = true
> repeat numberOfTimes {
>     //Do something, possibly set ok to false
> } while ok
> 
> This would repeat the loop a maximum of  'numberOfTimes', but could be ended early if some signal 'ok' is set to false (or, of course, by a break statement).
> 
> Thoughts?
> 
> Thanks!
> -Jason-
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