[swift-dev] Starter project: API to upgrade AnySequence to Any*Collection

[Dmitri Gribenko]

On Mon, Dec 7, 2015 at 2:27 PM, Jacob Bandes-Storch <jtbandes at gmail.com> wrote:
> What do you mean by "without copying the underlying collection"?

The original collection should be preserved through this upgrade, and
not, say, copied into a fresh Array.

> Is this
> specifically for the case where the AnySequence is wrapping a collection
> (which is not always the case)?

Exactly.

Dmitri

> On Mon, Dec 7, 2015 at 2:18 PM, Dmitri Gribenko via swift-dev
> <swift-dev at swift.org> wrote:
>>
>> It would require a proposal and a review, but the implementation is
>> more challenging here than the API design.  The proposal would be
>> trivial, just one extra API, if I'm imagining this correctly.
>>
>> Dmitri
>>
>> On Mon, Dec 7, 2015 at 2:10 PM, Austin Zheng <austinzheng at gmail.com>
>> wrote:
>> > Would this require a review/proposal, since it involves an API change?
>> >
>> > On Mon, Dec 7, 2015 at 2:08 PM, Dmitri Gribenko via swift-dev
>> > <swift-dev at swift.org> wrote:
>> >>
>> >> Hi,
>> >>
>> >> If someone looks for a starter project in the standard library with
>> >> intermediate complexity (prior experience with Swift generics
>> >> required), here's one.
>> >>
>> >> This is in the area of existential sequence and collection wrappers.
>> >>
>> >> Upgrading AnyForwardCollection to AnyRandomAccessCollection works:
>> >>
>> >> (swift) AnyRandomAccessCollection(AnyForwardCollection([1,2,3]))
>> >> // r2 : AnyRandomAccessCollection<Int>? =
>> >> Optional(Swift.AnyRandomAccessCollection<Swift.Int>(_box:
>> >> Swift._CollectionBox<Swift.Array<Swift.Int>>))
>> >>
>> >> Seems like we don't provide APIs to upgrade AnySequence to
>> >> Any*Collection:
>> >>
>> >> (swift) AnyRandomAccessCollection(AnySequence([1,2,3]))
>> >> <REPL Input>:1:1: error: cannot invoke initializer for type
>> >> 'AnyRandomAccessCollection<_>' with an argument list of type
>> >> '(AnySequence<Int>)'
>> >>
>> >> Of course, this should work without copying the underlying collection.
>> >>
>> >> https://bugs.swift.org/browse/SR-119
>> >>
>> >> 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 <gribozavr at gmail.com>*/
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>> >
>> >
>>
>>
>>
>> --
>> 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 <gribozavr at gmail.com>*/
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>
>



-- 
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 <gribozavr at gmail.com>*/