Parameterize the cartesian sorting

UncurryShwartz.hs

{-# LANGUAGE BlockArguments #-}

module CartesianProductEx where 
  
import Control.Arrow ((***))
import Data.List (sortOn)
import Test.Hspec (shouldBe)

-- given

data A = A1 | A2 deriving (Show, Enum, Bounded, Eq)

data B = B1 | B2 deriving (Show, Enum, Bounded, Eq)

allOf :: (Bounded a, Enum a) => [a]
allOf = [minBound .. maxBound]

-- define

evalB :: Int -> Int
evalB = error "not implemented"

evalA :: Int -> Int
evalA = error "not implemented"

composeEval :: Int -> Int -> Int
composeEval = error "not implemented"

-- such that

sortedAxB :: [(A, B)]
sortedAxB = sortOn
  do uncurry composeEval . (evalA . fromEnum *** evalB . fromEnum)
  do (,) <$> allOf <*> allOf

-- satisfies

main :: IO ()
main = sortedAxB `shouldBe` [(A2, B1), (A1, B1), (A1, B2), (A2, B2)]