Re: Does anybody know why boost::array does not support multiple dimensions?

From: Ivan Matek (libbooze_at_[hidden])
Date: 2022-01-03 10:43:54

On Mon, Jan 3, 2022 at 5:09 AM Peter Dimov via Boost <boost_at_[hidden]>
wrote:

> https://godbolt.org/z/afcMqMqrK

Very nice, I had similar idea in message with this link:
https://godbolt.org/z/Kzs6xbo5T
but just to double check:
no way to make initialization work with less {} because that is a language
limitation, right? I mean we could add std::initializer_list constructor
but then array is no longer aggregate?
In other words no way to turn this
    array<int, 2, 2, 3> a{{
        { { 1, 2, 3 }, { 4, 5, 6 } },
        { { 7, 8, 9 }, { 10, 11, 12 } }
    }};
into
    array<int, 2, 2, 3> a{
        { 1, 2, 3 }, { 4, 5, 6 },
        { 7, 8, 9 }, { 10, 11, 12 }
    };

without breaking aggregate property of array?
This is what I tried:
https://godbolt.org/z/MoPE8W79v

IMAO although this is less friendly for people that want to just initialize
md array with bunch of scalar values I think the syntax with using "last
level array" is nicer...
Obviously I did not think of all the edge cases so my opinion might change
rapidly.
One big problem I noticed is that we loose ability to group the
initialization(you can see the example in godbolt), but here it is inline.

    array<int, 2, 2, 3> a223{
         { 1, 2, 3 }, { 4, 5, 6 } ,
         { 7, 8, 9 }, { 10, 11, 12 }
    };
    // Unfortunately no way to group stuff with {} for more clarity
    //    array<int, 2, 2, 3> a223_grouped{
    //    {{ 1, 2, 3 }, { 4, 5, 6 }} ,
    //    {{ 7, 8, 9 }, { 10, 11, 12 } }
    //};