-module Typecheck (typeCheckExp, typeCheckStm, typeCheckVar) where
+module Typecheck (typeCheckExp, typeCheckStm, typeCheckVar, typeCheckFunction, addFunction, State(..)) where
import Abssyntax
-import Control.Monad.State
-import Data.Map as Map
+import Control.Monad.State hiding (State)
+import Data.Map as Map hiding (map)
import Prelude hiding (lookup)
type Types = [Map Ident Type]
+type Function = (Type, [Type])
+
+data State = State {variables::Types,functions::(Map Ident Function),function::Ident}
+
inList :: Eq a => a -> [a] -> Bool
inList _ [] = False
inList a (x:xs) = if a == x then True else inList a xs
-typeCheckExp :: (MonadState Types m) => Exp -> m Type
+assert :: Monad m => Bool -> String -> m ()
+assert True _ = return ()
+assert False s = fail s
+
+typeCheckExp :: (MonadState State m) => Exp -> m Type
typeCheckExp (BiOpExp e o e') = do
t1 <- typeCheckExp e
t2 <- typeCheckExp e'
- if not(t1 == t2) then fail "The parameters for the binary operator aren't equal"
- else if inList o [Eq,NEq] then return TBool
- else if not(t1 == TInt) then fail "The parameters need to be of type int"
- else if inList o [Plus,Minus,Times,Div]
- then return TInt
- else return TBool
+ assert (t1 == t2) "The parameters for the binary operator aren't equal"
+ if inList o [Eq,NEq] then return TBool
+ else do
+ assert (t1 == TInt) "The parameters need to be of type int"
+ if inList o [Plus,Minus,Times,Div]
+ then return TInt
+ else return TBool
typeCheckExp (EVar i) = typeCheckVar i
typeCheckExp (EAss i e) = do
t <- typeCheckVar i
t2 <- typeCheckExp e
- if t == t2 then return t else fail $ "Illegal to assign an expression of type "++show t2++" to variable "++show i++" of type "++show t
+ assert (t == t2) $ "Illegal to assign an expression of type "++show t2++" to variable "++show i++" of type "++show t
+ return t
typeCheckExp (EInt i) = return TInt
typeCheckExp (EBool b) = return TBool
typeCheckExp EReadI = return TInt
typeCheckExp EReadB = return TBool
-typeCheckExp (ExpT t e) = do
- t2 <- typeCheckExp e
- if t == t2 then return t else fail "Something went wrong ExpT is created with the wrong type"
-typeCheckExp EDefault = return NoType
typeCheckExp (EPost i op) = do
TInt <- typeCheckVar i
return TInt
TBool <- typeCheckExp e
return TBool
-typeCheckVar :: (MonadState Types m) => Ident -> m Type
+typeCheckVar :: (MonadState State m) => Ident -> m Type
typeCheckVar i = do
- ms <- get
- findVariable i ms
+ s <- get
+ findVariable i $ variables s
-findVariable :: (MonadState Types m) => Ident -> Types -> m Type
+findVariable :: (MonadState State m) => Ident -> Types -> m Type
findVariable i [] = fail $ "Variable "++show i++" not found in any scope."
findVariable i (m:ms) = if member i m then lookup i m else findVariable i ms
-typeCheckStm :: (MonadState Types m) => Stm -> m Type
-typeCheckStm SNoop = return NoType
+pushAndPop :: (MonadState State m) => m a -> m ()
+pushAndPop s = do
+ modify (\s -> s { variables = empty:variables s})
+ s
+ modify (\s -> s { variables = tail $ variables s})
+
+typeCheckStm :: (MonadState State m) => Stm -> m ()
+typeCheckStm SNoop = return ()
typeCheckStm (SExp e) = do
typeCheckExp e
- return NoType
-typeCheckStm (SBlock ss) = do
- modify (empty:)
- mapM typeCheckStm ss
- modify tail
- return NoType
+ return ()
+typeCheckStm (SBlock ss) = pushAndPop $ mapM typeCheckStm ss
typeCheckStm (SIf e s s') = do
TBool <- typeCheckExp e
- NoType <- typeCheckStm s
- NoType <- typeCheckStm s
- return NoType
+ pushAndPop $ typeCheckStm s
+ pushAndPop $ typeCheckStm s'
typeCheckStm (SWhile e s) = do
TBool <- typeCheckExp e
- NoType <- typeCheckStm s
- return NoType
+ pushAndPop $ typeCheckStm s
+typeCheckStm (SDeclD t i) = addVariable i t
typeCheckStm (SDecl t i e) = do
t2 <- typeCheckExp e
- if t == t2 || t2 == NoType then do
- (m:ms) <- get
- case insertLookupWithKey (\k a1 a2 -> a1) i t m of
- (Nothing,m') -> put (m':ms)
- _ -> fail $ "Duplicate variable declaration: "++show i
- return NoType
- else fail $ "Illegal to assign an expression of type "++show t2++" to variable "++show i++" of type "++show t
+ assert (t == t2) $ "Illegal to assign an expression of type "++show t2++" to variable "++show i++" of type "++show t
+ addVariable i t
typeCheckStm (SPrint e) = do
typeCheckExp e
- return NoType
+ return ()
+typeCheckStm (SReturn e) = do
+ t <- typeCheckExp e
+ state <- get
+ (t2,_) <- lookup (function state) $ functions state
+ assert (t == t2) $ "Illegal to return "++show t++" in function "++show (function state)++" which returns "++show t2
+
+
+addVariable :: (MonadState State m) => Ident -> Type -> m ()
+addVariable i t = do
+ s <- get
+ let (m:ms) = variables s in case insertLookupWithKey (\k a1 a2 -> a1) i t m of
+ (Nothing,m') -> modify (\s -> s{ variables = m':ms})
+ _ -> fail $ "Duplicate variable declaration: "++show i
+
+typeCheckFunction :: (MonadState State m) => Func -> m ()
+typeCheckFunction (Func t i d s) = do
+ state <- get
+ modify (\s -> s{variables=[empty], function=i})
+ mapM (\(Decl t i) -> addVariable i t) d
+ mapM typeCheckStm s
+ put state
+
+addFunction :: (MonadState State m) => Func -> m ()
+addFunction (Func t i d _) = do
+ s <- get
+ let m = functions s in case insertLookupWithKey (\k a1 a2 -> a1) i (t, map (\(Decl t i) -> t) d) m of
+ (Nothing,m') -> modify (\s -> s{ functions = m'})
+ _ -> fail $ "Duplicate variable declaration: "++show i
projects / proglang.git / blobdiff