cartesian_product.hs

module CartesianProduct where

import Data.List (group)

cprod :: [a] -> [a] -> [(a, a)]
cprod xs ys = [ (x, y) | x <- xs, y <- ys ]

cprodAll :: Eq a => [[a]] -> [(a, a)]
cprodAll [] = []
cprodAll (x:xs) = map head $ group $ concat (map (cprod x) xs) ++ cprodAll xs

main :: IO ()
main = do
    print $ cprodAll [[1, 2, 3], [1, 2], [3, 5], [1, 2], [8, 9, 10]]