sem.icl

   1 implementation module sem
   2
   3 import qualified Data.Map as Map
   4 from Data.Func import $
   5 import Data.Maybe
   6 import Data.Void
   7 import Data.Either
   8 import Data.Functor
   9 import Control.Applicative
  10 import Control.Monad
  11 import Control.Monad.State
  12 import Control.Monad.Identity
  13 import Math.Random
  14 import Control.Monad.Trans
  15 import StdMisc
  16 from StdFunc import id, const, o
  17 import StdString
  18 import StdTuple
  19 import StdList
  20 import StdBool
  21
  22 from Text import class Text(concat), instance Text String
  23
  24 import AST
  25 from parse import :: ParserOutput, :: Error
  26
  27 :: Gamma :== ('Map'.Map String Type, [String])
  28 :: Env a :== StateT Gamma (Either SemError) a
  29 //StateT (Gamma -> Either SemError (a, Gamma))
  30
  31 //we need to redefine this even though it is in Control.Monad.State
  32 instance MonadTrans (StateT Gamma) where
  33     liftT m = StateT \s-> m >>= \a-> return (a, s)
  34
  35 get = gets id
  36
  37 sem :: AST -> SemOutput
  38 sem (AST vd fd) = case runStateT m ('Map'.newMap, getRandomStream 1) of
  39     Left e = Left [e]
  40     Right ((vds, fds), gamma) = Right ((AST vds fds), gamma)
  41 where
  42     m :: Env ([VarDecl], [FunDecl])
  43     m = mapM semVarDecl vd >>= \vds ->
  44         mapM semFunDecl fd >>= \fds ->
  45         pure (vds, fds)
  46
  47 semFunDecl :: FunDecl -> Env FunDecl
  48 semFunDecl fd=:(FunDecl p f args mt vds stmts) =
  49     saveGamma >>= \gamma ->
  50     (case mt of
  51         Nothing = let t = IdType f in putIdent f t >>| pure t
  52         Just t = putIdent f t >>| pure t) >>= \ft ->
  53         matchFunctions args ft >>|
  54     mapM semVarDecl vds >>= \newvds->
  55     mapM_ (checkStmt $ resultType ft) stmts >>|
  56     restoreGamma gamma >>|
  57         pure (FunDecl p f args mt newvds stmts)
  58
  59 matchFunctions :: [String] Type -> Env Void
  60 matchFunctions [] (_ ->> _) = liftT $ Left $ Error "Niet genoeg argumentenerror"
  61 matchFunctions [] t = pure Void
  62 matchFunctions [x:xs] (t1 ->> t2) =
  63         modify (\(st, r)->('Map'.put x t1 st, r)) >>| matchFunctions xs t2
  64
  65 semVarDecl :: VarDecl -> Env VarDecl
  66 semVarDecl (VarDecl pos type ident ex) = unify type ex
  67     >>= \t-> putIdent ident t >>| (pure $ VarDecl pos t ident ex)
  68
  69 checkStmt ::Type Stmt -> Env Stmt
  70 checkStmt t (IfStmt c st se) = unify BoolType c >>| mapM (checkStmt t) st
  71     >>= \st1-> mapM (checkStmt t) se >>= \se1-> pure (IfStmt c st1 se1)
  72 checkStmt t w=:(WhileStmt c et) = unify BoolType c >>| mapM (checkStmt t) et
  73     >>= \et1-> pure w
  74 checkStmt t a=:(AssStmt (VarDef ident fs) e) = gets (\(st, r)->'Map'.get ident st)
  75     >>= \mt->case mt of
  76         Nothing = liftT $ Left $ UndeclaredVariableError zero ident
  77         Just t = unify t fs >>= \t1 -> unify t1 e >>| pure a
  78 checkStmt t r=:(FunStmt (FunCall f es)) = typeFun f es >>| pure r
  79 checkStmt VoidType r=:(ReturnStmt Nothing) = pure r
  80 checkStmt t r=:(ReturnStmt (Just e)) = unify t e >>| pure r
  81
  82 typeExpr :: Expr -> Env Type
  83 typeExpr (IntExpr _ _) = pure IntType
  84 typeExpr (CharExpr _ _) = pure CharType
  85 typeExpr (BoolExpr _ _) = pure BoolType
  86 typeExpr (Op1Expr p UnNegation expr) = unify BoolType expr
  87 typeExpr (Op1Expr p UnMinus expr) = unify IntType expr
  88 typeExpr (TupleExpr p (e1, e2)) = typeExpr e1
  89     >>= \t1-> typeExpr e2 >>= \t2-> pure $ TupleType (t1, t2)
  90 typeExpr (Op2Expr p e1 op e2)
  91 | isMember op [BiPlus, BiMinus, BiTimes, BiDivide, BiMod] =
  92         typeOp2 e1 e2 op [IntType] IntType
  93 | isMember op [BiEquals, BiUnEqual] =
  94         typeOp2 e1 e2 op [IntType, BoolType, CharType] BoolType
  95 | isMember op [BiLesser, BiGreater, BiLesserEq, BiGreaterEq] =
  96         typeOp2 e1 e2 op [IntType, CharType] BoolType
  97 | isMember op [BiAnd, BiOr] =
  98         typeOp2 e1 e2 op [BoolType] BoolType
  99 | op == BiCons = typeExpr e1 >>= \t1-> typeExpr e2
 100         >>= \t2-> unify (ListType t1) t2
 101 typeExpr (EmptyListExpr p) = freshIdent >>= \frsh-> let t = IdType frsh in
 102     putIdent frsh t >>| pure t
 103 typeExpr (FunExpr p (FunCall f es)) = typeFun f es
 104 typeExpr (VarExpr p (VarDef ident fs)) = gets (\(st, r)->'Map'.get ident st)
 105     >>= \mt->case mt of
 106         Nothing = liftT $ Left $ UndeclaredVariableError p ident
 107         Just t = unify t fs
 108 typeOp2 :: Expr Expr Op2 [Type] Type -> Env Type
 109 typeOp2 e1 e2 op ts ret = typeExpr e1 >>= \t1-> typeExpr e2 >>= \t2->
 110     unify t1 t2 >>= \t3->if (isMember t3 ts) (pure ret)
 111         (liftT $ Left $ OperatorError (extrPos e1) op t3)
 112
 113 buildFunctionType :: String [Expr] -> Env Type
 114 buildFunctionType frsh [] = let t = IdType frsh in putIdent frsh t >>| pure t
 115 buildFunctionType frsh [e:es] = (->>) <$> typeExpr e <*> buildFunctionType frsh es
 116
 117 unifyApp :: Type [Expr] -> Env Type
 118 unifyApp t [] = pure t
 119 unifyApp (tf1 ->> tf2) [t1:ts] = unify tf1 t1 >>| unifyApp tf2 ts
 120 unifyApp t1 t2 = liftT $ Left $ UnifyError zero t1 (IdType "[expressions, FIXME]")
 121
 122 typeFun :: String [Expr] -> Env Type
 123 typeFun f es = gets (\(st, r)->'Map'.get f st) >>= \mt-> case mt of
 124     Nothing = freshIdent >>= \frsh-> buildFunctionType frsh es
 125         >>= \ft-> putIdent f ft >>| (pure $ IdType frsh)
 126     Just t = unifyApp t es
 127
 128 resultType :: Type -> Type
 129 resultType (_ ->> t) = resultType t
 130 resultType t = t
 131
 132 class unify a :: Type a -> Env Type
 133
 134 instance unify [FieldSelector] where
 135     unify t [] = pure t
 136     unify (ListType t) [FieldHd:fs] = unify t fs
 137     unify t=:(ListType _) [FieldTl:fs] = unify t fs
 138     unify (TupleType (t, _)) [FieldFst:fs] = unify t fs
 139     unify (TupleType (_, t)) [FieldSnd:fs] = unify t fs
 140     unify t [fs:_] = liftT $ Left $ FieldSelectorError zero t fs
 141
 142 instance unify Expr where
 143         unify (_ ->> _) e = liftT $ Left $ ParseError (extrPos e)
 144                         "Expression cannot be a higher order function. Yet..."
 145         unify VoidType e = liftT $ Left $ ParseError (extrPos e)
 146                         "Expression cannot be a Void type."
 147         unify (IdType _) e = liftT $ Left $ ParseError (extrPos e)
 148                         "Expression cannot be an polymorf type."
 149     unify VarType e = typeExpr e
 150     //we have to cheat to decorate the error, can be done nicer?
 151     unify t e = StateT $ \s0 -> let res = runStateT m s0 in case res of
 152         Left err = Left $ decErr e err
 153         Right t = Right t //note, t :: (Type, Gamma)
 154     where m = typeExpr e >>= \tex-> unify t tex
 155
 156 instance unify Type where
 157         unify IntType IntType = pure IntType
 158         unify BoolType BoolType = pure BoolType
 159         unify CharType CharType = pure CharType
 160     unify (IdType i) t=:(IdType j) = replace i t >>| pure t
 161     unify t (IdType i) = unify (IdType i) t
 162     unify (IdType i) t = replace i t >>| pure t
 163     unify (ListType t1) (ListType t2) = unify t1 t2 >>| (pure $ ListType t1)
 164     unify (ta1 ->> ta2) (tb1 ->> tb2) = unify ta1 tb1 >>= \ta-> unify ta2 tb2
 165         >>= \tb-> pure (ta ->> tb)
 166         unify t1 t2 = liftT $ Left $ UnifyError zero t1 t2
 167
 168 instance zero Pos where
 169         zero = {line=0,col=0}
 170
 171 decErr :: Expr SemError -> SemError
 172 decErr e (UnifyError _ t1 t2) = UnifyError (extrPos e) t1 t2
 173 decErr e (FieldSelectorError _ t fs) = FieldSelectorError (extrPos e) t fs
 174 decErr e (ParseError _ s) = ParseError (extrPos e) s
 175 decErr e err = err
 176
 177 dc2 :: Expr (Either SemError a) -> Either SemError a
 178 dc2 e (Right t) = Right t
 179 dc2 e (Left err) = Left err
 180
 181 extrPos :: Expr -> Pos
 182 extrPos (VarExpr p _) = p
 183 extrPos (Op2Expr p _ _ _) = p
 184 extrPos (Op1Expr p _ _) = p
 185 extrPos (IntExpr p _) = p
 186 extrPos (CharExpr p _) = p
 187 extrPos (BoolExpr p _) = p
 188 extrPos (FunExpr p _) = p
 189 extrPos (EmptyListExpr p) = p
 190 extrPos (TupleExpr p _) = p
 191
 192 instance toString Gamma where
 193         toString (mp, _) = concat
 194                 [concat [k, ": ", toString v, "\n"]\\(k, v) <- 'Map'.toList mp]
 195
 196 getRandomStream :: Int -> [String]
 197 getRandomStream i = genIdents $ filter (isAlpha o toChar) (genRandInt i)
 198     where
 199         genIdents r = let (ic, r2) = splitAt 5 r in [toString ic: genIdents r2]
 200
 201 freshIdent :: Env String
 202 freshIdent = get >>= \(st, [ident:rest])-> put (st, rest)
 203     >>| case 'Map'.get ident st of
 204         Nothing = pure ident
 205         _       = freshIdent
 206
 207 putIdent :: String Type -> Env Void
 208 putIdent i t = gets (\(st, r)->'Map'.get i st) >>= \mt -> case mt of
 209     Nothing = modify (\(st, r)->('Map'.put i t st, r))
 210     Just t2 = unify t t2 >>= \t3-> modify (\(st, r)->('Map'.put i t3 st, r))
 211
 212 replace :: String Type -> Env Void
 213 replace ident type = get >>= \(st, fr)->put ('Map'.fromList $
 214         map (itupdate ident type) ('Map'.toList st), fr)
 215     where
 216         itupdate :: String Type (String, Type) -> (String, Type)
 217         itupdate ident newtype ov=:(key, IdType type) = if (ident == type)
 218             (key, newtype) ov
 219         itupdate ident newtype (key, TupleType (t1, t2))
 220         # (_, t1) = itupdate ident newtype (key, t1)
 221         # (_, t2) = itupdate ident newtype (key, t2)
 222         = (key, TupleType (t1, t2))
 223         itupdate ident newtype (key, ListType t1)
 224         # (_, t1) = itupdate ident newtype (key, t1)
 225         = (key, ListType t1)
 226         itupdate _ _ k = k
 227
 228 instance toString SemError where
 229     toString (ParseError p e) = concat [
 230         toString p,"SemError: ParseError: ", e]
 231     toString (Error e) = "SemError: " +++ e
 232     toString (UnifyError p t1 t2) = concat [
 233         toString p,
 234         "SemError: Cannot unify types. Expected: ",
 235         toString t1, ". Given: ", toString t2]
 236     toString (FieldSelectorError p t fs) = concat [
 237         toString p,
 238         "SemError: Cannot select ", toString fs, " from type: ",
 239         toString t]
 240     toString (OperatorError p o t) = concat [
 241         toString p,
 242         "SemError: No ", toString o, " for type ",
 243         toString t]
 244     toString (UndeclaredVariableError p ident) = concat [
 245         toString p, "SemError: identifier: ", ident, " undefined."]
 246
 247 saveGamma :: Env Gamma
 248 saveGamma = get
 249
 250 restoreGamma :: Gamma -> Env Void
 251 restoreGamma g = put g