I apologize in advance for posting yet another "suggestion" without having
full knowledge of all apocalypses, and I fear (for a very positive
meaning of "fear") that the answer will be: "but that is already
available".
Well, the point is that I wonder wether Perl6 will support cartesian
products between lists, i.e. an infix operator that will return a list of
arrayrefs "containing" ordered pairs from the originating lists.
Now, one possible difficulty with such an operator would be wrt what to do
with applying it twice or even more times. One would reasonably want it to
be associative in the obvious sense, but this won't happen (because
mathematically speaking (AxA)xA and Ax(AxA) are associative "only" up to
a *natural* isomorphism, which doesn't make much difference,
mathematically speaking, but indeed it does in a computer programming
context).
However I already know that I'll be told that I can cook up something like
that myself. But to be fair I think that the context in which such a beast
would be most useful would be that of iterating over multiple variables,
so one (well, I for one!) could be content with a special syntax for that,
instead.
Put more clearly, it is now common to see things like:
for my $x (1..10) {
for my $y (5..20) {
for my $text (qw/foo bar baz/) {
do_stgh_with $x, $y, $text;
}
}
}
and it would be very much in the phylosophy of Perl to allow for a very
concise syntax to obtain the same effect. I am aware of the zip operator,
but AFAICT it solves an equally common but completely different problem...
Michele
--
The amount of repetition repetition isn't that great.
- Ignacy Sawicki in comp.text.tex
thread "Bug in FeynMF's Queues?"
