A few quick points. Apologies for the brevity.
1. Please take a look at the stateful version of `sequence`
2. Additive, non-breaking proposals should be deferred until next month.
In regard to point 1, create a sequence that terminates on false.
So you can hack something up like this (of course, hopefully a little more
elegant)
extension Bool {
var optionalPresentation: Bool? { return self ? self : nil }
}
// a fake example of terminating check
func doSomething() -> Bool {
return arc4random_uniform(10) < 9 // 10% chance of ending
}
for nextItem in Swift.sequence(
state: doSomething().optionalPresentation,
next: { _ in return doSomething().optionalPresentation }) {
// use nextItem state here
// body of loop
}
Best,
-- E
> On Jul 18, 2016, at 11:52 AM, Braeden Profile via swift-evolution
> <[email protected]> wrote:
>
> Good morning, Swift community!
>
> I’ve come across a situation a number of times where I write code that has to
> try something one or more times using a `repeat…while` loop and the condition
> relies upon variables that should be declared within the scope of the loop.
>
> repeat
> {
> let success = doSomething()
> }
> while !success
>
> The compiler unnecessarily prohibits this: “Use of unresolved identifier
> four.” In this simple case, we can write:
>
> repeat
> { }
> while !doSomething()
>
> But in a more complex situation, we are forced to write:
>
> var success: Bool
> repeat
> {
> success = doSomething()
> }
> while !success
>
>
> We could change this so that the declarations within the top level scope of
> the loop are accessible from the condition.
>
> Thanks for reading my first post to the Swift discussion board!
> —Braeden
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