[swift-evolution] Add a while clause to for loops

[Erica Sadun]

> On Jun 8, 2016, at 1:07 PM, Xiaodi Wu via swift-evolution <swift-evolution at swift.org> wrote:
> I should add, on the topic of removing `where`, there would be a higher threshold for a successful proposal and I would have to convince people that the `where` clause is actually harmful. I do wonder if I could succeed in that endeavor. But when it comes to adding something like `while`, you've yet to convince me it offers more than just stylistic choice. IMO, that is insufficient for a proposal as consequential as adding syntax to the language itself (a much more serious addition than changing API in the stdlib, for example).

I think it would be valuable to defer this discussion until after WWDC to see how SE-0099 does. The core team's response to while exfoliation will greatly affect both how this suggestion goes.

(As is, if this moves forward, I'd say go with either where or while but not both, or eliminate while entirely.)

--- E