A.hs

module A where

data A = A

instance Show A where
  show _ = "-> A <-"

Main.hs

import A

main :: IO ()
main = print A

result.txt

(7.10.1)nushio@nuwheezy:import$ ghci Main.hs
GHCi, version 7.10.1: http://www.haskell.org/ghc/  :? for help
[1 of 2] Compiling A                ( A.hs, interpreted )
[2 of 2] Compiling Main             ( Main.hs, interpreted )
Ok, modules loaded: A, Main.
> main
-> A <-
> print A
-> A <-
>