a.hs

# ======================================== header.h =============================================
#define TRUE 1

# ======================================== X.hs =================================================
module X where

x = 1

# ======================================== Test.hs ==============================================

{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE CPP #-}

module Test where

import X
import GHC.Types
import Control.Monad
import Language.Haskell.TH

#include "header.h"

curryN :: Int -> Q Exp
curryN n = do
  f  <- newName "f"
  xs <- replicateM n (newName "x")
  let args = map VarP (f:xs)
      ntup = TupE (map VarE xs)
  return $ LamE args (AppE (VarE f) ntup)

data List a = Nil | Cons a (List a)

x = Cons 4 (Cons 2 Nil)

y = TRUE