On Fri, Jun 12, 2009 at 04:00:10PM -0300, Daniel Ruoso wrote:
: Em Sex, 2009-06-12 às 11:52 -0700, Jon Lang escreveu:
: > On Fri, Jun 12, 2009 at 11:51 AM, Daniel Ruoso<dan...@ruoso.com> wrote:
: > > Ok, There's one thing that is not clear in the thread, which is when an
: > > array is multidimensional or not...
: > > For instance:
: > > @a = (1, 2, 3; 4, 5, 6; 7, 8, 9);
: > > Will produce a flatten array, because list assignment causes flattening,
: > > so the dimensionality was lost.
: > Right. I should have said:
: > @@a = (1, 2, 3; 4, 5, 6; 7, 8, 9);
:
: The important point here is that it means we're dealing with a different
: type, so it can actually behave differently, so "@@a.rotate" would
: rotate the first dimension only..
:
: maybe @@a.rotate(1;1) would mean to rotate by 1 in the first dimension
: and by 1 in the second, producing
:
: (5, 6, 4; 8, 9, 7; 2, 3, 1)
I think captures are a bit of a red herring here. Arrays can be shaped
without the @@ sigil, and that is part of its type, so assignment to
@a and @.rotate can also do the right thing.
The @@ context was originally just a way of declaring a context that turns
nested captures into a multidimensional array at binding or
coercion time. So
@a := @@(1,2,3; 4,5,6; 7,8,9);
used to be defined as the same as
@a := [[1,2,3], [4,5,6], [7,8,9]];
Treating @@ as a capture sigil would make @@ coercion a no-op.
So perhaps @@ isn't the Texas form of a capture sigil after all.
Alternately, we leave @@ (or @%) meaning ¢ and instead let some
other syntax take over the "pay attention to the capture's structure"
semantics from @@. Maybe it's another use for the zen slice:
@a = (1,2,3; 4,5,6; 7,8,9); # 1..9
@a[] = (1,2,3; 4,5,6; 7,8,9); # [1,2,3], [4,5,6], [7,8,9]
Interestingly, that would mean that
@a = 1,2,3; # 1,2,3 3 elems
@a[] = 1,2,3; # [1,2,3] 1 elem!
much like subscripts assume .[1,2,3] is a 1-dim slice of three
elements, not a 3-dim vector pointing to a single element.
There's something slightly pleasing about the equivalence
@a = [1,2,3];
@a[] = 1,2,3;
Larry
