First off let me say that I love ruby. Ruby more or less taught me functional programming, which I love. But I do think that perl6 (which you may think is vaporware) is better. I only post about features which I can use right now in rakudo. With that said we shall move onward.

Update: the rest of this post, although still correct, is flawed. See comments for the Correct Ruby solution :-)

Fjord asked me about how to iterate over two lists at the same time in perl6. I have only had to do this a couple of times and I usually just end up doing a ghetto c-style for loop. In perl6 there is a better way. Check it!

Perl6:

1
2
3
my @a = 1,2,3;
my @b = 4,5,6;
for @a Z @b { say "$^a $^b" }

prints:

1 4
2 5
3 6

You may think, “fREW, ruby can do this and it does it exactly the same, if not better!”

Ruby1.8:

1
2
3
a = [1,2,3]
b = [4,5,6]
a.zip(b).each { puts "#{x[0]} #{x[1]}" }

Do you notice the subtle difference? In ruby we get [[1,4],[2,5],[3,6]] vs perl’s (1,4,2,5,3,6).

That may not seem like a big deal, but what if you want to iterate over three lists? Here’s perl6:

1
2
3
4
my @a = 1,2,3;
my @b = 4,5,6;
my @c = 7,8,9;
for @a Z @b Z @c { say "$^a $^b $^c" }

prints:

1 4 7
2 5 8
3 6 9

and Ruby:

1
2
3
4
5
6
a = [1,2,3]
b = [4,5,6]
c = [7,8,9]
a.zip(b).zip(c).each {
   puts "#{x[0][0]} #{x[0][1]} #{x[1]}"
}

That’s a drag! Anyway, I once read that there is a way to do this nicely in ruby, but I never could figure it out. I’d say the perl6 solution here is much nicer. Can someone prove me wrong?