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

From: Peter Dimov (pdimov_at_[hidden])
Date: 2022-01-01 14:21:33

Ivan Matek wrote:
> I don't know much about library development, but with variadic templates
> does not seem so hard, although every library development is much harder
> than regular user code.
> 
> Sure boost::array probably wants to support ancient compilers, but variadic
> version could exist only for "modern"(I do not consider >10y old standards
> modern) C++.
> 
> I found this std:: proposal
> http://www.open-
> std.org/JTC1/SC22/WG21/docs/papers/2013/n3794.html#Ch05
> from 9 y ago,
> also author seemed to have some working impl on github
> https://github.com/CTMacUser/ArrayMD/tree/master/include/boost/contain
> er
> 
> But I guess none of it ever progressed.
> 
> Does anybody knows more about this?
> It is not trivial since there are probably a ton of edge cases, typdefs,
> semantics(what should size return?, I would say array of dims) to deal with,
> but I think it would be a nice extension since I find nested std::array hideous
> (with current syntax), e.g.:
> 
> std::array<std::array<int,3>, 4> arr;
> 
> I would like to have this
> boost::array<int,4,3> arr;

boost::array<int[4], 3> should work, more or less. I've always felt that the
syntax should have been array<int[3]> instead, which naturally extends to
array<int[4][3]>, but it's too late now.