[boost] [array] Support for multidimensional arrays?

Subject: [boost] [array] Support for multidimensional arrays?
From: Peter Dimov (lists_at_[hidden])
Date: 2015-05-05 19:34:05

Currently, creating a multidimensional boost/std::array is a bit unwieldy:

    array<array<array<int, 5>, 4>, 3> a; // int a[3][4][5]
    a[2][3][4] = 5;

As a first step, we should consider enabling the element type T of array<T, 
N> to be an array type.

    array<int[4][5], 3> a; // int a[3][4][5]
    a[2][3][4] = 5;

This almost works already, except for the array interface functions 
specified and implemented in terms of, say, std::equal or std::fill.

It is an open question whether these standard algorithms should not be fixed 
themselves to work on array types, as swap_ranges has been, but for now, we 
can implement the array functions in a way that works.

Opinions on that part?

If we agree that this is a good idea, the next logical step would be to 
eliminate the special handling of the first extent and simply allow

    array<int[3][4][5]> a; // int a[3][4][5]
    a[2][3][4] = 5;