Matrix-type-friendly syntax and more

[Robert Jacques]

On Mon, 10 Oct 2011 08:46:05 -0400, kennytm <kennytm at gmail.com> wrote:
> Don <nospam at nospam.com> wrote:
>> On 10.10.2011 04:41, kenji hara wrote:
>>> 2011/10/10 bearophile<bearophileHUGS at lycos.com>:
>>>> So is this:
>>>> y[$-6, 0..$:2]
>>>>
>>>> Translated like this?
>>>> y.opIndex(y.opDollar!0 - 6, y.opSlice!1(0, y.opDollar!1, 2))
>>>
>>> I have no thought about it.
>>> I'm not sure that the additional stepping is really useful, but I
>>> think adding it into syntax is not impossible -- it might not conflict
>>> with associative array literal.
>>>
>>> Kenji Hara
>>
>> Personally, I think that since strided operations are so inefficient,
>> they should remain ugly.
>
> Slicing an nD static array is just as in/efficient as strides. That said,
> I'm still -1 on having a..b:c since (1) I see no practical need for strides
> and (2) even if we striding it doesn't need to be in the form a..b:c, e.g.
> arr[stride(0..$, 2)].
>

Regarding (1), from a computer vision/graphics perspective, being able to only operate on the red channel, for example, is very nice. And I use striding all the time in my CUDA code, but that's not as applicable in D, yet. Striding tends to be most useful for working with packed data of some kind.