There are a few modules on CPAN for generating combinations. For example given the lists
[ 'a','b','c' ] , [ 1, 2 ]
they produce

a 1
a 2
b 1 # two changes this iteration
b 2
c 1 # two changes this iteration
c 2

There's another ordering, where only one position at a time changes. And there's a name for that ordering which I've forgotten, so I haven't been able to search CPAN for it. It would produce the tuples in an order like so:

a 1
a 2
b 2
b 1
c 1
c 2

Can anyone refresh my memory as to what that ordering is called, and as a bonus, find me a module on CPAN that already produces combinations that way?

... I have tried the the obvious keywords "permute" and "combination" on metacpan but suspect I'm missing the right word... yes I could implement it from scratch, or take the output of one of the CPAN modules and reverse some records to get the desired ordering. But why re-invent a wheel, if it's already been invented.

In reply to Minimally changing combinations by Yary

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