On Thu, May 5, 2016 at 5:11 PM, Nate Cook <[email protected]> wrote:
> Thanks for the feedback, Dmitri &co, this all looks excellent! I'll work on
> updating the proposal.
>
>> On May 5, 2016, at 6:13 PM, Dmitri Gribenko <[email protected]> wrote:
>>
>> On Tue, May 3, 2016 at 8:57 PM, Chris Lattner via swift-evolution
>> <[email protected]> wrote:
>>> Hello Swift community,
>>>
>>> The review of "SE-0078: Implement a rotate algorithm, equivalent to
>>> std::rotate() in C++" begins now and runs through May 9.
>>
>> Hi,
>>
>> I'm posting this feedback on behalf of Dave Abrahams, Max Moiseev and
>> myself. We met and discussed the proposal in great detail.
>>
>> First of all, we want to thank Nate and Sergey for proposing this API,
>> which is an important and useful algorithm. We are generally in favor
>> of the proposal, but we would like to request a few changes.
>>
>> Could you make 'func rotate' a requirement in the MutableCollection
>> protocol? This allows selecting the best implementation for a given
>> concrete type, even when calling from generic code.
>>
>> Could you explain why do we need a special implementation of
>> 'reverse()' for RandomAccessCollection? We couldn't think of a
>> performance reason for this.
>
> With a bidirectional collection, you have to compare the high and low index
> at each iteration, stopping when low >= high (before indices were Comparable,
> this required two equality comparisons per iteration). With a random-access
> collection, you can optimize the loop to use a fixed number of iterations,
> which should be more efficient.
Good point! In that case, 'reverse()' should also be a protocol
requirement, to allow dispatch to the most efficient version.
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 <[email protected]>*/
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