Calculate n-ary Cartesian Product

Question

Given two lists, I can produce a list of all permutations the Cartesian Product of these two lists:

permute :: [a] -> [a] -> [[a]]
per         


        

Answer 1

I found Eric Lippert's article on computing Cartesian product with LINQ quite helpful in improving my understanding of what was going on. Here's a more-or-less direct translation:

cartesianProduct :: [[a]] -> [[a]]
cartesianProduct sequences = foldr aggregator [[]] sequences
                   where aggregator sequence accumulator = 
                         [ item:accseq |item <- sequence, accseq <- accumulator ]

Or with more "Haskell-y" terse, meaningless parameter names ;)

cartesianProduct = foldr f [[]]
                    where f l a = [ x:xs | x <- l, xs <- a ]

This winds up being quite similar to sclv posted after all.