On 10/28/05, Darren Duncan <[EMAIL PROTECTED]> wrote:
> One thing I would like to be able to do is this:
>
> @baz = cross([1,2],[3,4]); # yields ([1,3],[1,4],[2,3],[2,4])
>
> And alternately, this:
>
> for cross([1,2],[3,4]) -> $foo,$bar { ... } # loop has 4 iterations
I already proposed this in this thread:
http://groups.google.com/group/perl.perl6.language/browse_thread/thread/13f6317f6ca9229d/8046eddc50097a52?lnk=st&q=outer+product+luke+palmer&rnum=1#8046eddc50097a52
Where I called it "outer". Nowadays, instead of returning arrays, it
probably returns tuples:
for outer(1,2 ; 3,4) -> :($foo, $bar) {...}
So that it can be well-typed[1].
> On the other hand, perhaps something I actually want is something
> like the hyper-operation but with appropriately different syntax:
>
> ['a','b'] >>~<< ['c','d']
This was also discussed. The hot syntax at the time was:
('a','b') <<~>> ('c','d')
But we decided against it for a reason I can't recall at the moment.
For this, do:
map -> :($a, $b) { $a ~ $b } outer(<a b> ; <c d>)
Perhaps this could be written:
map &infix:<~>, *<<outer(<a b> ; <c d>)
But perhaps not.
Luke
[1] That is, if you had:
for outer(1,2 ; "foo", "bar") -> :($foo, $bar) {...}
The compiler could be sure that $foo is a Num and $bar is a Str.
