Multidimensional slice

[Nekroze]

On Wednesday, 19 December 2012 at 14:08:25 UTC, Rafael wrote:
> On Wednesday, 19 December 2012 at 13:28:24 UTC, Nekroze wrote:
>> On Wednesday, 19 December 2012 at 12:27:32 UTC, Rafael wrote:
>>> 1) It is possible to implement multiindex access using 
>>> opIndex* methods, moreover this is the simplest way to 
>>> multiindex access realization. So, we have [i, j, k] 
>>> notation. Next step after it - slices implementation and it 
>>> looks logical to save the same notation for it: [i1..i2, 
>>> j1..j2, k]. But it impossible, if I understand correctly.
>>>
>>> 2) On the other hand. Syntax via [i][j] leads to some 
>>> overhead: first index access [i] must return some light 
>>> accessor object (like range (or iterator)) which supports the 
>>> index access operation. But using this approach it is 
>>> possible to implement multidimensional slices. And this 
>>> means, that opIndex* methods with multiindex are not needed.
>>
>> Well if you are looking at operator overloading you can 
>> overload opSlice as described here 
>> http://dlang.org/operatoroverloading.html#Slice however i am 
>> not sure if you can defined multiple slices delimited by 
>> commas in the same [] block but it is worth a try.
>
> ...and we return to my initial question :)
>  The answer is: no, D is not support multidimension slices. 
> Possible way to solve it is to define some auxiliary structure 
> Slice, and use multiindex by following way:
> S [ Slice(0, $), 2] = A [ Slice(0, $), 2];

Instead of defining a struct for that why not allow index to take 
a uint array defining the lower and upper bounds of the slice. 
You may have to make the opSlice or opIndex a template however 
but I believe you should be able to take a uint[2] as an argument.

Atleast this way you dont have to add more structs to the mix and 
you can just do:
S[[0, S.length], 2] = A [[0, A.length], 2];
or some such, there may be a way of preserving the $ symbol but 
you would have to deal with that anyway if you made it an 
argument to a struct. perhaps a string mixin?