Circular Buffer

[Andrea Fontana]

On Tuesday, 11 February 2014 at 03:10:02 UTC, Jonathan Dunlap 
wrote:
> Wow! This is GREAT stuff. My use-case is slightly more complex, 
> and I'm not sure how to best apply this knowledge. The retro 
> reverses the array which is problematic in itself as well as 
> losing the starting index location. I have an array that I'd 
> like to elegantly "rotate". Best way I can show this is by 
> example of an imaginary rotate function:
>
> auto data = [1,2,3];
> assert( data.cycle.rotate(2) == [3,1,2] );
> assert( data.cycle.rotate(-2) == [2,3,1] );
>
> Perhaps what I'm doing is too complex requires me making my own 
> iterator or something. In my quest of writing readable 
> efficient code, I'm wondering what's the best route here. 
> Thanks :)
>
> On Monday, 10 February 2014 at 09:16:31 UTC, Gary Willoughby 
> wrote:
>> void main(string[] args)
>> {
>> 	auto data = [1,2,3];
>>
>> 	assert(data.cycle.take(5).array       == [1,2,3,1,2]);
>> 	assert(data.retro.cycle.take(5).array == [3,2,1,3,2]);
>> }

data.cycle.rotate(-2) == data.cycle(data.length + (-2 % 
data.length))
I guess you can implement your rotate function with this in mind.