gistfile1.txt

{-# LANGUAGE OverloadedStrings #-}

import Language.C.Data.InputStream
import Language.C.Syntax.AST
import Language.C.Data.Position
import Language.C.Parser    
import Language.C.Pretty

parse exp = execParser_ expressionP exp nopos 

exp1 :: InputStream
exp1 = "a > b ? a + b : b > c > d ? c : d ? a > b ? a : b : c > d ? c : d"      

exp2 :: InputStream
exp2 = "(a > b) ? (a + b) : (((b > c) > d) ? c : (d ? ((a > b) ? a : b) : ((c > d) ? c : d)))"                              

main :: IO ()
main = case (parse exp1, parse exp2) of
         (Right r1, Right r2) -> do 
           let s1 = show $ pretty $ r1
               s2 = show $ pretty $ r2

           if (show r1)==(show r2) then putStrLn "Same !"
           else putStrLn "Different !"

           putStrLn s1
           putStrLn s2
         _ -> putStrLn "Error !"