At 05:39 PM 8/9/00 +0200, Bart Lateur wrote:
>On Wed, 09 Aug 2000 09:41:22 -0400, Dan Sugalski wrote:
>
> >> >> @foo = @bar * 12;
>
> >> @foo = map { $_ * 12 } @bar;
>
> >>I don't see the need for a new notation.
> >
> >Well, compactness for one. With a scalar on one side it's less odd (it was
> >a bad example). When funkier, though:
> >
> > @foo = @bar * @baz;
> >
> >the expansion becomes less obvious and quite a bit larger, especially if
> >the arrays are multidimensional.
>
>(Isn't this becoming a "language" issue? -language CC'ed.)
Good call.
>If you're talking about matrix manipulations, I should immediately hold
>you back. Perl arrays are pretty bad as is for representing matrices.
>Don't let anybody tell you otherwise: Perl data structures are
>one-dimensionaly by nature.
That doesn't necessarily have to remain the case.
>For vector manipulation, I can understand that, *in principle*, but not
>really. I remember that a few functional language extensions have been
>proposed, including "apply a function (code block) to each combination
>of item i from the first list with item i of the second list, for each
>i". You can easily roll your own. It will do what you want, not what the
>implementors thought useful. For example: vector multiplication. What
>will @foo*@bar do? Will it return the scalar product
>(abs(@foo)*abs(@bar)*cos(angle), the vector product (returning a vector
>orthogonal to both others), or a matrix multiplication? If you roll your
>own, you can choose.
Choosing is a good thing, yep.
>No, I am more in favor of solid yet flexible overloading mechanism, so
>that you can use the appropriate module, which does the multiplication
>of your choice, and which still allows you to use something like the
>above notation. $foo and $bar will then be (vector or matrix) objects,
>instead of plain Perl arrays. Much like BigInt now.
Given that the default action of the multiply routine for an array in
non-scalar context would be to die, allowing user-overrides of the
functions would probably be a good idea... :)
Dan
--------------------------------------"it's like this"-------------------
Dan Sugalski even samurai
[EMAIL PROTECTED] have teddy bears and even
teddy bears get drunk
