Re: RFC 206 (v1) Array: @#arr for getting the dimensions of an array

[email protected] wrote:
> Perl6 RFC Librarian wrote:
>
> > This RFC proposes using @#array, analogous to $#array, to get the list
of
> > upper bounds for a multidimensional array @array. The length of @#array
> > would indicate the dimensionality of @array.
>
> That's fine. This RFC does not seem to touch on the question what
> $#array should be for a multidim array (e.g., $#array == $#{flatten @a}
> or rather undef). Or is that dealt with in another RFC?
>
It's dealt with in RFC 203 'Arrays: Notation for declaring and creating
arrays':

<quote>
These arrays support I<all> the same syntax as lists. Therefore any
description of syntax for a 'list' also applies to an 'array', and visa
versa
</quote>

Therefore:

  my int @a = ([1,2], [3,4]);
  $#a == 1; # As it does in Perl 5 (for untyped lists)

  my @b :bounds(2,2);
  $#b == 2; # Because @b== ([undef,undef,undef],
            #               [undef,undef,undef],
            #               [undef,undef,undef])