calc.hs

編譯器 像YACC的編譯及語法產生器

-- parser produced by Happy Version 1.13

module Calc where
import Char

data HappyAbsSyn t5 t6 t7
	= HappyTerminal Token
	| HappyErrorToken Int
	| HappyAbsSyn4 (Exp)
	| HappyAbsSyn5 t5
	| HappyAbsSyn6 t6
	| HappyAbsSyn7 t7

action_0 (8) = happyShift action_2
action_0 (10) = happyShift action_7
action_0 (11) = happyShift action_8
action_0 (17) = happyShift action_9
action_0 (4) = happyGoto action_3
action_0 (5) = happyGoto action_4
action_0 (6) = happyGoto action_5
action_0 (7) = happyGoto action_6
action_0 _ = happyFail

action_1 (8) = happyShift action_2
action_1 _ = happyFail

action_2 (11) = happyShift action_15
action_2 _ = happyFail

action_3 (19) = happyAccept
action_3 _ = happyFail

action_4 (13) = happyShift action_13
action_4 (14) = happyShift action_14
action_4 _ = happyReduce_2

action_5 (15) = happyShift action_11
action_5 (16) = happyShift action_12
action_5 _ = happyReduce_5

action_6 _ = happyReduce_8

action_7 _ = happyReduce_9

action_8 _ = happyReduce_10

action_9 (8) = happyShift action_2
action_9 (10) = happyShift action_7
action_9 (11) = happyShift action_8
action_9 (17) = happyShift action_9
action_9 (4) = happyGoto action_10
action_9 (5) = happyGoto action_4
action_9 (6) = happyGoto action_5
action_9 (7) = happyGoto action_6
action_9 _ = happyFail

action_10 (18) = happyShift action_21
action_10 _ = happyFail

action_11 (10) = happyShift action_7
action_11 (11) = happyShift action_8
action_11 (17) = happyShift action_9
action_11 (7) = happyGoto action_20
action_11 _ = happyFail

action_12 (10) = happyShift action_7
action_12 (11) = happyShift action_8
action_12 (17) = happyShift action_9
action_12 (7) = happyGoto action_19
action_12 _ = happyFail

action_13 (10) = happyShift action_7
action_13 (11) = happyShift action_8
action_13 (17) = happyShift action_9
action_13 (6) = happyGoto action_18
action_13 (7) = happyGoto action_6
action_13 _ = happyFail

action_14 (10) = happyShift action_7
action_14 (11) = happyShift action_8
action_14 (17) = happyShift action_9
action_14 (6) = happyGoto action_17
action_14 (7) = happyGoto action_6
action_14 _ = happyFail

action_15 (12) = happyShift action_16
action_15 _ = happyFail

action_16 (8) = happyShift action_2
action_16 (10) = happyShift action_7
action_16 (11) = happyShift action_8
action_16 (17) = happyShift action_9
action_16 (4) = happyGoto action_22
action_16 (5) = happyGoto action_4
action_16 (6) = happyGoto action_5
action_16 (7) = happyGoto action_6
action_16 _ = happyFail

action_17 (15) = happyShift action_11
action_17 (16) = happyShift action_12
action_17 _ = happyReduce_4

action_18 (15) = happyShift action_11
action_18 (16) = happyShift action_12
action_18 _ = happyReduce_3

action_19 _ = happyReduce_7

action_20 _ = happyReduce_6

action_21 _ = happyReduce_11

action_22 (9) = happyShift action_23
action_22 _ = happyFail

action_23 (8) = happyShift action_2
action_23 (10) = happyShift action_7
action_23 (11) = happyShift action_8
action_23 (17) = happyShift action_9
action_23 (4) = happyGoto action_24
action_23 (5) = happyGoto action_4
action_23 (6) = happyGoto action_5
action_23 (7) = happyGoto action_6
action_23 _ = happyFail

action_24 _ = happyReduce_1

happyReduce_1 = happyReduce 6 4 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 4 happyReduction_2
happyReduction_2 (HappyAbsSyn5  happy_var_1)
	 =  HappyAbsSyn4
		 (Exp1 happy_var_1
	)
happyReduction_2 _  = notHappyAtAll 

happyReduce_3 = happySpecReduce_3 5 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 5 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 5 happyReduction_5
happyReduction_5 (HappyAbsSyn6  happy_var_1)
	 =  HappyAbsSyn5
		 (Term happy_var_1
	)
happyReduction_5 _  = notHappyAtAll 

happyReduce_6 = happySpecReduce_3 6 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 6 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 6 happyReduction_8
happyReduction_8 (HappyAbsSyn7  happy_var_1)
	 =  HappyAbsSyn6
		 (Factor happy_var_1
	)
happyReduction_8 _  = notHappyAtAll 

happyReduce_9 = happySpecReduce_1 7 happyReduction_9
happyReduction_9 (HappyTerminal (TokenInt happy_var_1))
	 =  HappyAbsSyn7
		 (Int happy_var_1
	)
happyReduction_9 _  = notHappyAtAll 

happyReduce_10 = happySpecReduce_1 7 happyReduction_10
happyReduction_10 (HappyTerminal (TokenVar happy_var_1))
	 =  HappyAbsSyn7
		 (Var happy_var_1
	)
happyReduction_10 _  = notHappyAtAll 

happyReduce_11 = happySpecReduce_3 7 happyReduction_11
happyReduction_11 _
	(HappyAbsSyn4  happy_var_2)
	_
	 =  HappyAbsSyn7
		 (Brack happy_var_2
	)
happyReduction_11 _ _ _  = notHappyAtAll 

happyNewToken action sts stk [] =
	action 19 19 (error "reading EOF!") (HappyState action) sts stk []

happyNewToken action sts stk (tk:tks) =
	let cont i = action i i tk (HappyState action) sts stk tks in
	case tk of {
	TokenLet -> cont 8;
	TokenIn -> cont 9;
	TokenInt happy_dollar_dollar -> cont 10;
	TokenVar happy_dollar_dollar -> cont 11;
	TokenEq -> cont 12;
	TokenPlus -> cont 13;
	TokenMinus -> cont 14;
	TokenTimes -> cont 15;
	TokenDiv -> cont 16;
	TokenOB -> cont 17;
	TokenCB -> cont 18;
	_ -> happyError tks
	}

happyThen = \m k -> k m
happyReturn = \a -> a
happyThen1 = happyThen
happyReturn1 = \a tks -> a

calc tks = happyThen (happyParse action_0 tks) (\x -> case x of {HappyAbsSyn4 z -> happyReturn z; _other -> notHappyAtAll })

happySeq = happyDontSeq

happyError :: [Token] -> a
happyError _ = error ("Parse error\n")



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
{-# LINE 1 "GenericTemplate.hs" #-}
-- $Id: GenericTemplate.hs,v 1.23 2002/05/23 09:24:27 simonmar Exp $

{-# LINE 15 "GenericTemplate.hs" #-}






















































infixr 9 `HappyStk`
data HappyStk a = HappyStk a (HappyStk a)

-----------------------------------------------------------------------------
-- starting the parse

happyParse start_state = happyNewToken start_state notHappyAtAll notHappyAtAll

-----------------------------------------------------------------------------
-- Accepting the parse

happyAccept j tk st sts (HappyStk ans _) = 

					   (happyReturn1 ans)

-----------------------------------------------------------------------------
-- Arrays only: do the next action

{-# LINE 150 "GenericTemplate.hs" #-}


-----------------------------------------------------------------------------
-- HappyState data type (not arrays)



newtype HappyState b c = HappyState
        (Int ->                    -- token number
         Int ->                    -- token number (yes, again)
         b ->                           -- token semantic value
         HappyState b c ->              -- current state
         [HappyState b c] ->            -- state stack
         c)



-----------------------------------------------------------------------------
-- Shifting a token

happyShift new_state (1) tk st sts stk@(x `HappyStk` _) =
     let i = (case x of { HappyErrorToken (i) -> i }) in
--     trace "shifting the error token" $
     new_state i i tk (HappyState (new_state)) ((st):(sts)) (stk)

happyShift new_state i tk st sts stk =
     happyNewToken new_state ((st):(sts)) ((HappyTerminal (tk))`HappyStk`stk)

-- happyReduce is specialised for the common cases.

happySpecReduce_0 i fn (1) tk st sts stk
     = happyFail (1) tk st sts stk
happySpecReduce_0 nt fn j tk st@((HappyState (action))) sts stk
     = action nt j tk st ((st):(sts)) (fn `HappyStk` stk)

happySpecReduce_1 i fn (1) tk st sts stk
     = happyFail (1) tk st sts stk
happySpecReduce_1 nt fn j tk _ sts@(((st@(HappyState (action))):(_))) (v1`HappyStk`stk')
     = let r = fn v1 in
       happySeq r (action nt j tk st sts (r `HappyStk` stk'))

happySpecReduce_2 i fn (1) tk st sts stk
     = happyFail (1) tk st sts stk
happySpecReduce_2 nt fn j tk _ ((_):(sts@(((st@(HappyState (action))):(_))))) (v1`HappyStk`v2`HappyStk`stk')
     = let r = fn v1 v2 in
       happySeq r (action nt j tk st sts (r `HappyStk` stk'))

happySpecReduce_3 i fn (1) tk st sts stk
     = happyFail (1) tk st sts stk
happySpecReduce_3 nt fn j tk _ ((_):(((_):(sts@(((st@(HappyState (action))):(_))))))) (v1`HappyStk`v2`HappyStk`v3`HappyStk`stk')
     = let r = fn v1 v2 v3 in
       happySeq r (action nt j tk st sts (r `HappyStk` stk'))

happyReduce k i fn (1) tk st sts stk
     = happyFail (1) tk st sts stk
happyReduce k nt fn j tk st sts stk
     = case happyDrop (k - ((1) :: Int)) sts of
	 sts1@(((st1@(HappyState (action))):(_))) ->
        	let r = fn stk in  -- it doesn't hurt to always seq here...
       		happyDoSeq r (action nt j tk st1 sts1 r)

happyMonadReduce k nt fn (1) tk st sts stk
     = happyFail (1) tk st sts stk
happyMonadReduce k nt fn j tk st sts stk =
        happyThen1 (fn stk) (\r -> action nt j tk st1 sts1 (r `HappyStk` drop_stk))
       where sts1@(((st1@(HappyState (action))):(_))) = happyDrop k ((st):(sts))
             drop_stk = happyDropStk k stk

happyDrop (0) l = l
happyDrop n ((_):(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 action j tk st = action j j tk (HappyState action)


-----------------------------------------------------------------------------
-- Error recovery ((1) is the error token)

-- parse error if we are in recovery and we fail again
happyFail  (1) tk old_st _ stk =
--	trace "failing" $ 
    	happyError


{-  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  (1) tk old_st (((HappyState (action))):(sts)) 
						(saved_tok `HappyStk` _ `HappyStk` stk) =
--	trace ("discarding state, depth " ++ show (length stk))  $
	action (1) (1) tk (HappyState (action)) sts ((saved_tok`HappyStk`stk))
-}

-- Enter error recovery: generate an error token,
--                       save the old token and carry on.
happyFail  i tk (HappyState (action)) sts stk =
--      trace "entering error recovery" $
	action (1) (1) tk (HappyState (action)) sts ( (HappyErrorToken (i)) `HappyStk` stk)

-- Internal happy errors:

notHappyAtAll = error "Internal Happy error\n"

-----------------------------------------------------------------------------
-- Hack to get the typechecker to accept our action functions







-----------------------------------------------------------------------------
-- 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 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.