On Mon, May 2, 2016 at 3:08 PM, Karl via swift-evolution
<swift-evolution@swift.org> wrote:
> So, just confirming that the following is going to change:
>
> —————
> var string = "test"
> let origLen = 4
> let indexOne = string.startIndex
>
> string.appendContentsOf("ANOTHERTEST")
>
> let indexTwo = indexOne.advancedBy(origLen, limit: string.endIndex)
>
> assert(indexTwo<string.endIndex)
> indexTwo.successor() //<--- fatal error: cannot
> increment endIndex
> —————
Hi Karl,
Yes, this code would start working.
> Is this a consequence of the index needing to know its originating string for
> successor() purposes?
That would be a plausible explanation, but I think that would be too
simple to be true :) This code should even work in the current model,
but the current (buggy) behavior is caused by String indices keeping
an extra strong reference to the underlying storage, so the mutation
actually detaches the index from the updated string storage.
> Once this is implemented, will String.Index be portable across string
> instances (presuming you bounds-check them, as I did above)?
Yes, within the prefix that was common to all strings and was created
in a common mutation history.
Dmitri
--
main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
(j){printf("%d\n",i);}}} /*Dmitri Gribenko <griboz...@gmail.com>*/
_______________________________________________
swift-evolution mailing list
swift-evolution@swift.org
https://lists.swift.org/mailman/listinfo/swift-evolution
