Buddha Buck wrote:
> The main problem I see are these:
>
> @array = ([1,2],[3,4]); # 2-dimensional array, using LOL syntax
> print $array[[1,1]]; # prints 4, OK
> print $array[1]; # prints ?????
> print $array[[1,1,1]]; # prints ?????
> print $array[[1]]; # prints ?????
>
> According to RFC 204, $array[1] should return [3,4], $array[[1]] should
> return (3,4), and $array[[1,1,1]] should cause a runtime error.
>
> Interestingly enough, my original version of RFC204 had all three of
> the "questionable" print statements be runtime errors -- I don't like
> LOL-semantics for multidimensional arrays. Somehow, it got changed
> when being passed from me through Jerry to the RFC Librarian. I didn't
> bother to reread it after it got posted -- I knew what it said -- so I
> didn't notice the change.
>
Sorry Buddha--I thought that we were agreed on the "arrays are list of
lists" thing, so that I was just adding clarification. We can say in Perl 5:
@array = ([1,2],[3,4]); # 2-dimensional array, using LOL syntax
print $array[1];
I don't think there's any sensible way of changing this to an error in Perl
6 (or any reason to, either). That's why I clarified that in your RFC. Then
there's the question of @array[[1]]. If that fails to deref automagically,
then 1d arrays and multidim arrays will suddenly have different interfaces
(since a 1d array doesn't contain refs, while n-dim arrays do).
> $array[[1,2]] = (1,2,3,4); # Sets the line at (1,2) to (1,2,3,4)
>
> Huh? That's a scalar on the right, a list on the left? Should that
> set $array[[1,2]] to 4?
>
It should. The RFC should say:
@array[[1,2]] = (1,2,3,4); # Sets the line at (1,2) to (1,2,3,4)
> > Puh. I'd prefer
> >
> > my @a = @$array[0];
> >
> > which is shorter anyway. ;-) Currently, this does the wrong thing,
> > and I think that maybe the prefix precedence should be fixed so that
> >
> > @$ary[0]
> >
> > is the same as
> >
> > @{$ary[0]}
> >
> > Or doe people find it intuitive that this returns a slice of an array
> > pointed to by $ary?
>
> I'd find
>
> my @a = @array[0;];
>
> to be nicer -- no references visible, unambiguous, same number of
> characters as @$array[0], and symmetrical with
>
> my @b = @array[;0];
>
> for a different dimension. It isn't easy to do that with LOL notation.
>
I agree with both of you. It would be nice if @$ precedence worked as Bart
specified, but I still think that arrays should be arrays.
