すごいHaskell読書会 in 大阪 #4 @Nushio さん問題にたいする答案

main.hs

import Parupunte
import Prelude hiding ((+), (*))
import qualified Prelude as P

main = do
  print $ (2 + 8) * (3 + 7)       -- should print 37
  print $ (2 P.+ 8) P.* (3 P.+ 7) -- should print 100

Parupunte.hs

module Parupunte ((+), (*)) where

import qualified Prelude

(+) = (Prelude.*)
(*) = (Prelude.+)