content: {-# LANGUAGE CPP, MagicHash, BangPatterns #-}
  import Data.Char
  import Data.Array
  import GHC.Exts
  import System.IO
  import System.IO.Unsafe
  import Debug.Trace
  
  import Control.Applicative (Applicative(..))
  import Control.Monad (liftM, ap)
  
  -- parser produced by Happy Version 1.16
  
  data HappyAbsSyn
  	= HappyTerminal Token
  	| HappyErrorToken Int
  	| HappyAbsSyn4 (Exp)
  	| HappyAbsSyn5 (Exp1)
  	| HappyAbsSyn6 (Term)
  	| HappyAbsSyn7 (Factor)
  
  happyActOffsets :: HappyAddr
  happyActOffsets = HappyA# "\x01\x00\x25\x00\x1e\x00\x1b\x00\x1d\x00\x18\x00\x00\x00\x00\x00\x00\x00\x01\x00\xf8\xff\x03\x00\x03\x00\x03\x00\x03\x00\x20\x00\x01\x00\x18\x00\x18\x00\x00\x00\x00\x00\x00\x00\x0a\x00\x01\x00\x00\x00\x00\x00"#
  
  happyGotoOffsets :: HappyAddr
  happyGotoOffsets = HappyA# "\x1a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x16\x00\x00\x00\x07\x00\xfe\xff\x1c\x00\x06\x00\x00\x00\x12\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x0e\x00\x00\x00\x00\x00"#
  
  happyDefActions :: HappyAddr
  happyDefActions = HappyA# "\x00\x00\x00\x00\x00\x00\x00\x00\xfd\xff\xfa\xff\xf7\xff\xf6\xff\xf5\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xfb\xff\xfc\xff\xf8\xff\xf9\xff\xf4\xff\x00\x00\x00\x00\xfe\xff"#
  
  happyCheck :: HappyAddr
  happyCheck = HappyA# "\xff\xff\x03\x00\x01\x00\x0b\x00\x03\x00\x04\x00\x03\x00\x04\x00\x02\x00\x03\x00\x03\x00\x0a\x00\x02\x00\x0a\x00\x00\x00\x01\x00\x02\x00\x03\x00\x00\x00\x01\x00\x02\x00\x03\x00\x00\x00\x01\x00\x02\x00\x03\x00\x00\x00\x01\x00\x02\x00\x03\x00\x02\x00\x03\x00\x08\x00\x09\x00\x04\x00\x06\x00\x07\x00\x05\x00\x01\x00\x0c\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"#
  
  happyTable :: HappyAddr
  happyTable = HappyA# "\x00\x00\x13\x00\x03\x00\x16\x00\x08\x00\x09\x00\x08\x00\x09\x00\x11\x00\x06\x00\x14\x00\x0a\x00\x18\x00\x0a\x00\x18\x00\x04\x00\x05\x00\x06\x00\x16\x00\x04\x00\x05\x00\x06\x00\x0a\x00\x04\x00\x05\x00\x06\x00\x03\x00\x04\x00\x05\x00\x06\x00\x12\x00\x06\x00\x0c\x00\x0d\x00\x10\x00\x0e\x00\x0f\x00\x11\x00\x03\x00\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"#
  
  happyReduceArr = array (1, 11) [
  	(1 , happyReduce_1),
  	(2 , happyReduce_2),
  	(3 , happyReduce_3),
  	(4 , happyReduce_4),
  	(5 , happyReduce_5),
  	(6 , happyReduce_6),
  	(7 , happyReduce_7),
  	(8 , happyReduce_8),
  	(9 , happyReduce_9),
  	(10 , happyReduce_10),
  	(11 , happyReduce_11)
  	]
  
  happy_n_terms = 13 :: Int
  happy_n_nonterms = 4 :: Int
  
  happyReduce_1 = happyReduce 6# 0# happyReduction_1
  happyReduction_1 ((HappyAbsSyn4  happy_var_6) `HappyStk`
  	_ `HappyStk`
  	(HappyAbsSyn4  happy_var_4) `HappyStk`
  	_ `HappyStk`
  	(HappyTerminal (TokenVar happy_var_2)) `HappyStk`
  	_ `HappyStk`
  	happyRest)
  	 = HappyAbsSyn4
  		 (Let happy_var_2 happy_var_4 happy_var_6
  	) `HappyStk` happyRest
  
  happyReduce_2 = happySpecReduce_1  0# happyReduction_2
  happyReduction_2 (HappyAbsSyn5  happy_var_1)
  	 =  HappyAbsSyn4
  		 (Exp1 happy_var_1
  	)
  happyReduction_2 _  = notHappyAtAll
  
  happyReduce_3 = happySpecReduce_3  1# happyReduction_3
  happyReduction_3 (HappyAbsSyn6  happy_var_3)
  	_
  	(HappyAbsSyn5  happy_var_1)
  	 =  HappyAbsSyn5
  		 (Plus happy_var_1 happy_var_3
  	)
  happyReduction_3 _ _ _  = notHappyAtAll
  
  happyReduce_4 = happySpecReduce_3  1# happyReduction_4
  happyReduction_4 (HappyAbsSyn6  happy_var_3)
  	_
  	(HappyAbsSyn5  happy_var_1)
  	 =  HappyAbsSyn5
  		 (Minus happy_var_1 happy_var_3
  	)
  happyReduction_4 _ _ _  = notHappyAtAll
  
  happyReduce_5 = happySpecReduce_1  1# happyReduction_5
  happyReduction_5 (HappyAbsSyn6  happy_var_1)
  	 =  HappyAbsSyn5
  		 (Term happy_var_1
  	)
  happyReduction_5 _  = notHappyAtAll
  
  happyReduce_6 = happySpecReduce_3  2# happyReduction_6
  happyReduction_6 (HappyAbsSyn7  happy_var_3)
  	_
  	(HappyAbsSyn6  happy_var_1)
  	 =  HappyAbsSyn6
  		 (Times happy_var_1 happy_var_3
  	)
  happyReduction_6 _ _ _  = notHappyAtAll
  
  happyReduce_7 = happySpecReduce_3  2# happyReduction_7
  happyReduction_7 (HappyAbsSyn7  happy_var_3)
  	_
  	(HappyAbsSyn6  happy_var_1)
  	 =  HappyAbsSyn6
  		 (Div happy_var_1 happy_var_3
  	)
  happyReduction_7 _ _ _  = notHappyAtAll
  
  happyReduce_8 = happySpecReduce_1  2# happyReduction_8
  happyReduction_8 (HappyAbsSyn7  happy_var_1)
  	 =  HappyAbsSyn6
  		 (Factor happy_var_1
  	)
  happyReduction_8 _  = notHappyAtAll
  
  happyReduce_9 = happySpecReduce_1  3# happyReduction_9
  happyReduction_9 (HappyTerminal (TokenInt happy_var_1))
  	 =  HappyAbsSyn7
  		 (Int happy_var_1
  	)
  happyReduction_9 _  = notHappyAtAll
  
  happyReduce_10 = happySpecReduce_1  3# happyReduction_10
  happyReduction_10 (HappyTerminal (TokenVar happy_var_1))
  	 =  HappyAbsSyn7
  		 (Var happy_var_1
  	)
  happyReduction_10 _  = notHappyAtAll
  
  happyReduce_11 = happySpecReduce_3  3# happyReduction_11
  happyReduction_11 _
  	(HappyAbsSyn4  happy_var_2)
  	_
  	 =  HappyAbsSyn7
  		 (Brack happy_var_2
  	)
  happyReduction_11 _ _ _  = notHappyAtAll
  
  happyNewToken action sts stk [] =
  	happyDoAction 12# notHappyAtAll action sts stk []
  
  happyNewToken action sts stk (tk:tks) =
  	let cont i = happyDoAction i tk action sts stk tks in
  	case tk of {
  	TokenLet -> cont 1#;
  	TokenIn -> cont 2#;
  	TokenInt happy_dollar_dollar -> cont 3#;
  	TokenVar happy_dollar_dollar -> cont 4#;
  	TokenEq -> cont 5#;
  	TokenPlus -> cont 6#;
  	TokenMinus -> cont 7#;
  	TokenTimes -> cont 8#;
  	TokenDiv -> cont 9#;
  	TokenOB -> cont 10#;
  	TokenCB -> cont 11#;
  	_ -> happyError' (tk:tks)
  	}
  
  happyError_ tk tks = happyError' (tk:tks)
  
  newtype HappyIdentity a = HappyIdentity a
  happyIdentity = HappyIdentity
  happyRunIdentity (HappyIdentity a) = a
  
  instance Functor HappyIdentity where
      fmap = liftM
  
  instance Applicative HappyIdentity where
      pure = HappyIdentity
      (<*>) = ap
  
  instance Monad HappyIdentity where
      (HappyIdentity p) >>= q = q p
  
  
  happyThen :: () => HappyIdentity a -> (a -> HappyIdentity b) -> HappyIdentity b
  happyThen = (>>=)
  happyReturn :: () => a -> HappyIdentity a
  happyReturn = (return)
  happyThen1 m k tks = (>>=) m (\a -> k a tks)
  happyReturn1 :: () => a -> b -> HappyIdentity a
  happyReturn1 = \a tks -> (return) a
  happyError' :: () => [Token] -> HappyIdentity a
  happyError' = HappyIdentity . happyError
  
  calc tks = happyRunIdentity happySomeParser where
    happySomeParser = happyThen (happyParse 0# tks) (\x -> case x of {HappyAbsSyn4 z -> happyReturn z; _other -> notHappyAtAll })
  
  happySeq = happyDontSeq
  
  
  happyError tks = error "Parse error"
  
  
  
  data Exp  = Let String Exp Exp | Exp1 Exp1
  data Exp1 = Plus Exp1 Term | Minus Exp1 Term | Term Term
  data Term = Times Term Factor | Div Term Factor | Factor Factor
  data Factor = Int Int | Var String | Brack Exp
  
  
  
  data Token
  	= TokenLet
  	| TokenIn
  	| TokenInt Int
  	| TokenVar String
  	| TokenEq
  	| TokenPlus
  	| TokenMinus
  	| TokenTimes
  	| TokenDiv
  	| TokenOB
  	| TokenCB
  
  
  
  lexer :: String -> [Token]
  lexer [] = []
  lexer (c:cs)
  	| isSpace c = lexer cs
  	| isAlpha c = lexVar (c:cs)
  	| isDigit c = lexNum (c:cs)
  lexer ('=':cs) = TokenEq : lexer cs
  lexer ('+':cs) = TokenPlus : lexer cs
  lexer ('-':cs) = TokenMinus : lexer cs
  lexer ('*':cs) = TokenTimes : lexer cs
  lexer ('/':cs) = TokenDiv : lexer cs
  lexer ('(':cs) = TokenOB : lexer cs
  lexer (')':cs) = TokenCB : lexer cs
  
  lexNum cs = TokenInt (read num) : lexer rest
  	where (num,rest) = span isDigit cs
  
  lexVar cs =
     case span isAlpha cs of
  	("let",rest) -> TokenLet : lexer rest
  	("in",rest)  -> TokenIn : lexer rest
  	(var,rest)   -> TokenVar var : lexer rest
  
  
  
  
  runCalc :: String -> Exp
  runCalc = calc . lexer
  
  
  
  main = case runCalc "1 + 2 + 3" of {
  	(Exp1 (Plus (Plus (Term (Factor (Int 1))) (Factor (Int 2))) (Factor (Int 3))))  ->
  	case runCalc "1 * 2 + 3" of {
  	(Exp1 (Plus (Term (Times (Factor (Int 1)) (Int 2))) (Factor (Int 3)))) ->
  	case runCalc "1 + 2 * 3" of {
  	(Exp1 (Plus (Term (Factor (Int 1))) (Times (Factor (Int 2)) (Int 3)))) ->
  	case runCalc "let x = 2 in x * (x - 2)" of {
  	(Let "x" (Exp1 (Term (Factor (Int 2)))) (Exp1 (Term (Times (Factor (Var "x")) (Brack (Exp1 (Minus (Term (Factor (Var "x"))) (Factor (Int 2))))))))) -> print "Test works\n";
  	_ -> quit } ; _ -> quit } ; _ -> quit } ; _ -> quit }
  quit = print "Test failed\n"
  {-# LINE 1 "GenericTemplate.hs" #-}
  {-# LINE 1 "<built-in>" #-}
  {-# LINE 1 "<command line>" #-}
  {-# LINE 1 "GenericTemplate.hs" #-}
  -- Id: GenericTemplate.hs,v 1.26 2005/01/14 14:47:22 simonmar Exp
  
  {-# LINE 28 "GenericTemplate.hs" #-}
  
  
  data Happy_IntList = HappyCons Int# Happy_IntList
  
  
  
  
  
  {-# LINE 49 "GenericTemplate.hs" #-}
  
  {-# LINE 59 "GenericTemplate.hs" #-}
  
  
  
  happyTrace string expr = unsafePerformIO $ do
      hPutStr stderr string
      return expr
  
  
  
  
  infixr 9 `HappyStk`
  data HappyStk a = HappyStk a (HappyStk a)
  
  -----------------------------------------------------------------------------
  -- starting the parse
  
  happyParse start_state = happyNewToken start_state notHappyAtAll notHappyAtAll
  
  -----------------------------------------------------------------------------
  -- Accepting the parse
  
  -- If the current token is 0#, it means we've just accepted a partial
  -- parse (a %partial parser).  We must ignore the saved token on the top of
  -- the stack in this case.
  happyAccept 0# tk st sts (_ `HappyStk` ans `HappyStk` _) =
  	happyReturn1 ans
  happyAccept j tk st sts (HappyStk ans _) =
  	(happyTcHack j (happyTcHack st)) (happyReturn1 ans)
  
  -----------------------------------------------------------------------------
  -- Arrays only: do the next action
  
  
  
  happyDoAction i tk st
  	= (happyTrace ("state: " ++ show (I# (st)) ++  		      ",\ttoken: " ++ show (I# (i)) ++ 		      ",\taction: ")) $
  
  
  	  case action of
  		0#		  -> (happyTrace ("fail.\n")) $
  				     happyFail i tk st
  		-1# 	  -> (happyTrace ("accept.\n")) $
  				     happyAccept i tk st
  		n | isTrue# (n <# (0# :: Int#)) -> (happyTrace ("reduce (rule " ++ show rule 						 ++ ")")) $
  
  				     (happyReduceArr ! rule) i tk st
  				     where rule = (I# ((negateInt# ((n +# (1# :: Int#))))))
  		n		  -> (happyTrace ("shift, enter state " 						 ++ show (I# (new_state)) 						 ++ "\n")) $
  
  
  				     happyShift new_state i tk st
  				     where new_state = (n -# (1# :: Int#))
     where off    = indexShortOffAddr happyActOffsets st
  	 off_i  = (off +# i)
  	 check  = if isTrue# (off_i >=# (0# :: Int#))
  			then isTrue# (indexShortOffAddr happyCheck off_i ==#  i)
  			else False
   	 action | check     = indexShortOffAddr happyTable off_i
  		| otherwise = indexShortOffAddr happyDefActions st
  
  {-# LINE 127 "GenericTemplate.hs" #-}
  
  
  indexShortOffAddr (HappyA# arr) off =
  	narrow16Int# i
    where
  	i = word2Int# ((high `uncheckedShiftL#` 8#) `or#` low)
  	high = int2Word# (ord# (indexCharOffAddr# arr (off' +# 1#)))
  	low  = int2Word# (ord# (indexCharOffAddr# arr off'))
  	off' = off *# 2#
  
  
  
  
  
  data HappyAddr = HappyA# Addr#
  
  
  
  
  -----------------------------------------------------------------------------
  -- HappyState data type (not arrays)
  
  {-# LINE 170 "GenericTemplate.hs" #-}
  
  -----------------------------------------------------------------------------
  -- Shifting a token
  
  happyShift new_state 0# tk st sts stk@(x `HappyStk` _) =
       let i = (case x of { HappyErrorToken (I# (i)) -> i }) in
  --     trace "shifting the error token" $
       happyDoAction i tk new_state (HappyCons (st) (sts)) (stk)
  
  happyShift new_state i tk st sts stk =
       happyNewToken new_state (HappyCons (st) (sts)) ((HappyTerminal (tk))`HappyStk`stk)
  
  -- happyReduce is specialised for the common cases.
  
  happySpecReduce_0 i fn 0# tk st sts stk
       = happyFail 0# tk st sts stk
  happySpecReduce_0 nt fn j tk st@((action)) sts stk
       = happyGoto nt j tk st (HappyCons (st) (sts)) (fn `HappyStk` stk)
  
  happySpecReduce_1 i fn 0# tk st sts stk
       = happyFail 0# tk st sts stk
  happySpecReduce_1 nt fn j tk _ sts@((HappyCons (st@(action)) (_))) (v1`HappyStk`stk')
       = let r = fn v1 in
         happySeq r (happyGoto nt j tk st sts (r `HappyStk` stk'))
  
  happySpecReduce_2 i fn 0# tk st sts stk
       = happyFail 0# tk st sts stk
  happySpecReduce_2 nt fn j tk _ (HappyCons (_) (sts@((HappyCons (st@(action)) (_))))) (v1`HappyStk`v2`HappyStk`stk')
       = let r = fn v1 v2 in
         happySeq r (happyGoto nt j tk st sts (r `HappyStk` stk'))
  
  happySpecReduce_3 i fn 0# tk st sts stk
       = happyFail 0# tk st sts stk
  happySpecReduce_3 nt fn j tk _ (HappyCons (_) ((HappyCons (_) (sts@((HappyCons (st@(action)) (_))))))) (v1`HappyStk`v2`HappyStk`v3`HappyStk`stk')
       = let r = fn v1 v2 v3 in
         happySeq r (happyGoto nt j tk st sts (r `HappyStk` stk'))
  
  happyReduce k i fn 0# tk st sts stk
       = happyFail 0# tk st sts stk
  happyReduce k nt fn j tk st sts stk
       = case happyDrop (k -# (1# :: Int#)) sts of
  	 !sts1@((HappyCons (st1@(action)) (_))) ->
          	let r = fn stk in  -- it doesn't hurt to always seq here...
         		happyDoSeq r (happyGoto nt j tk st1 sts1 r)
  
  happyMonadReduce k nt fn 0# tk st sts stk
       = happyFail 0# tk st sts stk
  happyMonadReduce k nt fn j tk st sts stk =
          happyThen1 (fn stk tk) (\r -> happyGoto nt j tk st1 sts1 (r `HappyStk` drop_stk))
         where !sts1@((HappyCons (st1@(action)) (_))) = happyDrop k (HappyCons (st) (sts))
               drop_stk = happyDropStk k stk
  
  happyMonad2Reduce k nt fn 0# tk st sts stk
       = happyFail 0# tk st sts stk
  happyMonad2Reduce k nt fn j tk st sts stk =
         happyThen1 (fn stk tk) (\r -> happyNewToken new_state sts1 (r `HappyStk` drop_stk))
         where !sts1@((HappyCons (st1@(action)) (_))) = happyDrop k (HappyCons (st) (sts))
               drop_stk = happyDropStk k stk
  
               off    = indexShortOffAddr happyGotoOffsets st1
               off_i  = (off +# nt)
               new_state = indexShortOffAddr happyTable off_i
  
  
  
  
  happyDrop 0# l = l
  happyDrop n (HappyCons (_) (t)) = happyDrop (n -# (1# :: Int#)) t
  
  happyDropStk 0# l = l
  happyDropStk n (x `HappyStk` xs) = happyDropStk (n -# (1#::Int#)) xs
  
  -----------------------------------------------------------------------------
  -- Moving to a new state after a reduction
  
  
  happyGoto nt j tk st =
     (happyTrace (", goto state " ++ show (I# (new_state)) ++ "\n")) $
     happyDoAction j tk new_state
     where off    = indexShortOffAddr happyGotoOffsets st
  	 off_i  = (off +# nt)
   	 new_state = indexShortOffAddr happyTable off_i
  
  
  
  
  -----------------------------------------------------------------------------
  -- Error recovery (0# is the error token)
  
  -- parse error if we are in recovery and we fail again
  happyFail  0# tk old_st _ stk =
  --	trace "failing" $
      	happyError_ tk
  
  {-  We don't need state discarding for our restricted implementation of
      "error".  In fact, it can cause some bogus parses, so I've disabled it
      for now --SDM
  
  -- discard a state
  happyFail  0# tk old_st (HappyCons ((action)) (sts))
  						(saved_tok `HappyStk` _ `HappyStk` stk) =
  --	trace ("discarding state, depth " ++ show (length stk))  $
  	happyDoAction 0# tk action sts ((saved_tok`HappyStk`stk))
  -}
  
  -- Enter error recovery: generate an error token,
  --                       save the old token and carry on.
  happyFail  i tk (action) sts stk =
  --      trace "entering error recovery" $
  	happyDoAction 0# tk action sts ( (HappyErrorToken (I# (i))) `HappyStk` stk)
  
  -- Internal happy errors:
  
  notHappyAtAll = error "Internal Happy error\n"
  
  -----------------------------------------------------------------------------
  -- Hack to get the typechecker to accept our action functions
  
  
  happyTcHack :: Int# -> a -> a
  happyTcHack x y = y
  {-# INLINE happyTcHack #-}
  
  
  -----------------------------------------------------------------------------
  -- Seq-ing.  If the --strict flag is given, then Happy emits
  --	happySeq = happyDoSeq
  -- otherwise it emits
  -- 	happySeq = happyDontSeq
  
  happyDoSeq, happyDontSeq :: a -> b -> b
  happyDoSeq   a b = a `seq` b
  happyDontSeq a b = b
  
  -----------------------------------------------------------------------------
  -- Don't inline any functions from the template.  GHC has a nasty habit
  -- of deciding to inline happyGoto everywhere, which increases the size of
  -- the generated parser quite a bit.
  
  
  {-# NOINLINE happyDoAction #-}
  {-# NOINLINE happyTable #-}
  {-# NOINLINE happyCheck #-}
  {-# NOINLINE happyActOffsets #-}
  {-# NOINLINE happyGotoOffsets #-}
  {-# NOINLINE happyDefActions #-}
  
  {-# NOINLINE happyShift #-}
  {-# NOINLINE happySpecReduce_0 #-}
  {-# NOINLINE happySpecReduce_1 #-}
  {-# NOINLINE happySpecReduce_2 #-}
  {-# NOINLINE happySpecReduce_3 #-}
  {-# NOINLINE happyReduce #-}
  {-# NOINLINE happyMonadReduce #-}
  {-# NOINLINE happyGoto #-}
  {-# NOINLINE happyFail #-}
  
  -- end of Happy Template.
  