Cartesian product of two lists in Elm

cartesian.elm

import Html exposing (text)

main =
  text <| toString <| cartesian ["a", "b", "c"] [1..5]
  
cartesian : List a -> List b -> List (a,b)
cartesian xs ys =
  List.concatMap
    ( \x -> List.map ( \y -> (x, y) ) ys )
    xs
    
cartesianExtra xs ys =
  List.Extra.lift2 (,) xs ys