1 implementation module sem
3 import qualified Data.Map as Map
4 from Data.Func import $
8 import Control.Applicative
10 import Control.Monad.State
11 import Control.Monad.Identity
13 from StdFunc import id, const
17 from Text import class Text(concat), instance Text String
20 from parse import :: ParserOutput, :: Error
22 :: Gamma :== 'Map'.Map String Type
23 :: Env a :== (State Gamma (Either SemError a))
25 get = state $ \s -> (s,s)
27 putIdent :: String Type -> Env Void
28 putIdent i t = gets ('Map'.get i) >>= \mt -> case mt of
29 Nothing = pure <$> modify ('Map'.put i t)
30 Just t2 = unify t t2 >>= \r -> case r of
31 Left e = pure $ Left e
32 Right t3 = pure <$> modify ('Map'.put i t3)
34 instance toString SemError where
35 toString (ParseError p e) = concat [
36 toString p,"SemError: ParseError: ", e]
37 toString (Error e) = "SemError: " +++ e
38 toString (UnifyErrorStub t1 t2) = toString (UnifyError {line=0,col=0} t1
40 toString (UnifyError p t1 t2) = concat [
42 "SemError: Cannot unify types. Expected: ",
43 toString t1, ". Given: ", toString t2]
45 sem :: AST -> SemOutput
47 # (eithervds, gamma) = runState (mapM semVarDecl vd) 'Map'.newMap
48 # (eitherfds, gamma) = runState (mapM semFunDecl fd) gamma
49 = case splitEithers eithervds of
50 (Left errs) = Left $ errs ++ [x\\(Left x)<-eitherfds]
51 (Right vds) = case splitEithers eitherfds of
52 (Left errs) = Left errs
53 (Right fds) = Right $ AST vds fds
55 splitEithers :: [Either a b] -> Either [a] [b]
56 splitEithers [] = Right []
57 splitEithers [Right x:xs] = splitEithers xs >>= \rest->Right [x:rest]
58 splitEithers xs = Left $ [x\\(Left x)<-xs]
60 semFunDecl :: FunDecl -> Env FunDecl
61 semFunDecl f = pure $ Right f
63 semVarDecl :: VarDecl -> Env VarDecl
64 semVarDecl vd=:(VarDecl pos type ident ex) = unify type ex
66 Left err = pure $ Left err
67 Right t = putIdent ident t >>| pure (Right $ VarDecl pos t ident ex)
69 typeExpr :: Expr -> Env Type
70 typeExpr (IntExpr _ _) = pure $ Right IntType
71 typeExpr (CharExpr _ _) = pure $ Right CharType
72 typeExpr (BoolExpr _ _) = pure $ Right BoolType
73 typeExpr (Op1Expr p UnNegation expr) = unify BoolType expr
74 typeExpr (Op1Expr p UnMinus expr) = unify IntType expr
75 typeExpr (TupleExpr p (e1, e2)) = typeExpr e1
76 >>= \ete1->typeExpr e2 >>= \ete2->pure (
77 ete1 >>= \te1->ete2 >>= \te2->Right $ TupleType (te1, te2))
79 typeExpr (Op2Expr p e1 BiPlus e2) = unify IntType e1 >>| unify IntType e2
80 typeExpr (Op2Expr p e1 BiMinus e2) = unify IntType e1 >>| unify IntType e2
81 typeExpr (Op2Expr p e1 BiTimes e2) = unify IntType e1 >>| unify IntType e2
82 typeExpr (Op2Expr p e1 BiDivide e2) = unify IntType e1 >>| unify IntType e2
83 typeExpr (Op2Expr p e1 BiMod e2) = unify IntType e1 >>| unify IntType e2
85 typeExpr (Op2Expr p e1 BiEquals e2) =
86 typeExpr (Op2Expr p e1 BiUnEqual e2) = undef
88 typeExpr (Op2Expr p e1 BiLesser e2) = undef
89 typeExpr (Op2Expr p e1 BiGreater e2) = undef
90 typeExpr (Op2Expr p e1 BiLesserEq e2) = undef
91 typeExpr (Op2Expr p e1 BiGreaterEq e2) = undef
93 typeExpr (Op2Expr p e1 BiAnd e2) = undef
94 typeExpr (Op2Expr p e1 BiOr e2) = undef
96 typeExpr (Op2Expr p e1 BiCons e2) = undef
97 //typeExpr (FunExpr Pos FunCall) = undef
98 //typeExpr (EmptyListExpr Pos) = undef
99 //typeExpr (VarExpr Pos VarDef) = undef //when checking var-expr, be sure to
100 //put the infered type
103 class unify a :: Type a -> Env Type
105 instance unify Expr where
106 unify (_ ->> _) e = pure $ Left $ ParseError (extrPos e)
107 "Expression cannot be a higher order function. Yet..."
108 unify VoidType e = pure $ Left $ ParseError (extrPos e)
109 "Expression cannot be a Void type."
110 unify (IdType _) e = pure $ Left $ ParseError (extrPos e)
111 "Expression cannot be an polymorf type."
112 unify VarType e = typeExpr e
113 unify t e = typeExpr e
114 >>= \eithertype->case eithertype of
115 Left e = pure $ Left e
116 Right tex = unify t tex >>= \eitherun->case eitherun of
117 Left err = pure $ Left $ decErr e err
118 Right t = pure $ Right t
120 instance unify Type where
121 unify IntType IntType = pure $ Right IntType
122 unify BoolType BoolType = pure $ Right BoolType
123 unify CharType CharType = pure $ Right CharType
124 unify t1 t2 = pure $ Left $ UnifyError zero t1 t2
126 instance zero Pos where
127 zero = {line=0,col=0}
129 decErr :: Expr SemError -> SemError
130 decErr e (UnifyError _ t1 t2) = UnifyError (extrPos e) t1 t2
131 decErr e (ParseError _ s) = ParseError (extrPos e) s
134 extrPos :: Expr -> Pos
135 extrPos (VarExpr p _) = p
136 extrPos (Op2Expr p _ _ _) = p
137 extrPos (Op1Expr p _ _) = p
138 extrPos (IntExpr p _) = p
139 extrPos (CharExpr p _) = p
140 extrPos (BoolExpr p _) = p
141 extrPos (FunExpr p _) = p
142 extrPos (EmptyListExpr p) = p
143 extrPos (TupleExpr p _) = p