As we have discussed throughout this thread, the initial proposal was modified to include alternative subscript methods instead of modifying the default operator/subscript behaviour. The first draft is here: https://github.com/luish/swift-evolution/blob/more-lenient-subscripts/proposals/nnnn-more-lenient-collections-subscripts.md
I've also put this as a gist so that you can leave comments with respect to the proposal document itself. Any suggestion or help is very welcome. https://gist.github.com/luish/832c34ee913159f130d97a914810dbd8 Regards, - Luis On Mon, Apr 11, 2016 at 1:23 PM, Luis Henrique B. Sousa <[email protected]> wrote: > This proposal seeks to provide a safer ..< (aka half-open range operator) > in order to avoid **Array index out of range** errors in execution time. > > Here is my first draft for this proposal: > https://github.com/luish/swift-evolution/blob/half-open-range-operator/proposals/nnnn-safer-half-open-range-operator.md > > In short, doing that in Swift causes a runtime error: > > let a = [1,2,3] > let b = a[0..<5] > print(b) > > > Error running code: > > fatal error: Array index out of range > > The proposed solution is to slice the array returning all elements that > are below the half-open operator, even though the number of elements is > lesser than the ending of the half-open operator. So the example above > would return [1,2,3]. > We can see this very behaviour in other languages, such as Python and Ruby > as shown in the proposal draft. > > This would eliminate the need for verifications on the array size before > slicing it -- and consequently runtime errors in cases when the programmer > didn't. > > Viewing that it is my very first proposal, any feedback will be helpful. > Thanks! > > Luis Henrique Borges > @luishborges >
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