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 >>= \fds1 ->
  45         mapM semFunDecl fds1 >>= \fds2 ->
  46         pure (vds, fds2)
  47
  48 semFunDecl :: FunDecl -> Env FunDecl
  49 semFunDecl fd=:(FunDecl p f args mt vds stmts) =
  50     (case mt of
  51         Nothing = genType args >>= \infft->putIdent f infft >>| pure infft
  52         Just t = putIdent f t >>| pure t) >>= \ft ->
  53     saveGamma >>= \gamma ->
  54         matchFunctions args ft >>= \tres->
  55     mapM semVarDecl vds >>= \newvds->
  56     mapM (checkStmt tres) stmts >>= \newstmts->
  57         pure IntType >>= \returntype->
  58         case mt of
  59                 Nothing = reconstructType args returntype
  60                 >>= \ftype->restoreGamma gamma
  61                         >>| putIdent f ftype >>| pure (
  62                         FunDecl p f args (Just ftype) newvds newstmts)
  63                 Just t = restoreGamma gamma
  64                         >>| pure (FunDecl p f args mt newvds newstmts)
  65
  66 reconstructType :: [String] Type -> Env Type
  67 reconstructType [] t = pure t
  68 reconstructType [x:xs] t = gets (\(st, r)->'Map'.get x st)
  69         >>= \mtype->case mtype of
  70                 Nothing = liftT $ Left $ Error "Not used ????"
  71                 Just type = reconstructType xs t >>= \resttype->pure (type ->> resttype)
  72
  73 genType :: [String] -> Env Type
  74 genType [] = freshIdent >>= \fi->pure $ IdType fi
  75 genType [x:xs] = liftM2 (->>) (freshIdent >>= \fi->pure $ IdType fi)
  76         (genType xs)
  77
  78 matchFunctions :: [String] Type -> Env Type
  79 matchFunctions [] (_ ->> _) = liftT $ Left $ Error "Not enough arguments"
  80 matchFunctions _ (VoidType ->> _) = liftT $ Left $ Error "Cannot have a void type in the middle of the function definition"
  81 matchFunctions [x:xs] (t1 ->> t2) =
  82         modify (\(st, r)->('Map'.put x t1 st, r)) >>| matchFunctions xs t2
  83 matchFunctions [] t = pure t
  84 matchFunctions _ t = liftT $ Left $ Error "Too much argumnts"
  85
  86 semVarDecl :: VarDecl -> Env VarDecl
  87 semVarDecl (VarDecl pos type ident ex) = unify type ex
  88     >>= \t-> putIdent ident t >>| (pure $ VarDecl pos t ident ex)
  89
  90 checkStmt ::Type Stmt -> Env Stmt
  91 checkStmt t (IfStmt c st se) = unify BoolType c >>| mapM (checkStmt t) st
  92     >>= \st1-> mapM (checkStmt t) se >>= \se1-> pure (IfStmt c st1 se1)
  93 checkStmt t w=:(WhileStmt c et) = unify BoolType c >>| mapM (checkStmt t) et
  94     >>= \et1-> pure w
  95 checkStmt t a=:(AssStmt (VarDef ident fs) e) = gets (\(st, r)->'Map'.get ident st)
  96     >>= \mt->case mt of
  97         Nothing = liftT $ Left $ UndeclaredVariableError zero ident
  98         Just t = unify t fs >>= \t1 -> unify t1 e >>| pure a
  99 checkStmt t r=:(FunStmt (FunCall f es)) = typeFun f es >>| pure r
 100 checkStmt VoidType r=:(ReturnStmt Nothing) = pure r
 101 checkStmt t r=:(ReturnStmt (Just e)) = unify t e >>| pure r
 102
 103 typeExpr :: Expr -> Env Type
 104 typeExpr (IntExpr _ _) = pure IntType
 105 typeExpr (CharExpr _ _) = pure CharType
 106 typeExpr (BoolExpr _ _) = pure BoolType
 107 typeExpr (Op1Expr p UnNegation expr) = unify BoolType expr
 108 typeExpr (Op1Expr p UnMinus expr) = unify IntType expr
 109 typeExpr (TupleExpr p (e1, e2)) = typeExpr e1
 110     >>= \t1-> typeExpr e2 >>= \t2-> pure $ TupleType (t1, t2)
 111 typeExpr (Op2Expr p e1 op e2)
 112 | isMember op [BiPlus, BiMinus, BiTimes, BiDivide, BiMod] =
 113         typeOp2 e1 e2 op [IntType] IntType
 114 | isMember op [BiEquals, BiUnEqual] =
 115         typeOp2 e1 e2 op [IntType, BoolType, CharType] BoolType
 116 | isMember op [BiLesser, BiGreater, BiLesserEq, BiGreaterEq] =
 117         typeOp2 e1 e2 op [IntType, CharType] BoolType
 118 | isMember op [BiAnd, BiOr] =
 119         typeOp2 e1 e2 op [BoolType] BoolType
 120 | op == BiCons = typeExpr e1 >>= \t1-> typeExpr e2
 121         >>= \t2-> unify (ListType t1) t2
 122 typeExpr (EmptyListExpr p) = freshIdent >>= \frsh-> let t = IdType frsh in
 123     putIdent frsh t >>| pure t
 124 typeExpr (FunExpr p (FunCall f es)) = typeFun f es
 125 typeExpr (VarExpr p (VarDef ident fs)) = gets (\(st, r)->'Map'.get ident st)
 126     >>= \mt->case mt of
 127         Nothing = liftT $ Left $ UndeclaredVariableError p ident
 128         Just t = unify t fs
 129
 130 typeOp2 :: Expr Expr Op2 [Type] Type -> Env Type
 131 typeOp2 e1 e2 op ts ret = typeExpr e1 >>= \t1-> typeExpr e2 >>= \t2->
 132     unify t1 t2 >>= \t3->if (isMember t3 ts) (pure ret)
 133         (liftT $ Left $ OperatorError (extrPos e1) op t3)
 134
 135 buildFunctionType :: String [Expr] -> Env Type
 136 buildFunctionType frsh [] = let t = IdType frsh in putIdent frsh t >>| pure t
 137 buildFunctionType frsh [e:es] = (->>) <$> typeExpr e <*> buildFunctionType frsh es
 138
 139 unifyApp :: Type [Expr] -> Env Type
 140 unifyApp t [] = pure t
 141 unifyApp (tf1 ->> tf2) [t1:ts] = unify tf1 t1 >>| unifyApp tf2 ts
 142 unifyApp t1 t2 = liftT $ Left $ UnifyError zero t1 (IdType "[expressions, FIXME]")
 143
 144 typeFun :: String [Expr] -> Env Type
 145 typeFun f es = gets (\(st, r)->'Map'.get f st) >>= \mt-> case mt of
 146     Nothing = freshIdent >>= \frsh-> buildFunctionType frsh es
 147         >>= \ft-> putIdent f ft >>| (pure $ IdType frsh)
 148     Just t = unifyApp t es
 149
 150 resultType :: Type -> Type
 151 resultType (_ ->> t) = resultType t
 152 resultType t = t
 153
 154 class unify a :: Type a -> Env Type
 155
 156 instance unify [FieldSelector] where
 157     unify t [] = pure t
 158     unify (ListType t) [FieldHd:fs] = unify t fs
 159     unify t=:(ListType _) [FieldTl:fs] = unify t fs
 160     unify (TupleType (t, _)) [FieldFst:fs] = unify t fs
 161     unify (TupleType (_, t)) [FieldSnd:fs] = unify t fs
 162     unify t [fs:_] = liftT $ Left $ FieldSelectorError zero t fs
 163
 164 instance unify Expr where
 165         unify (_ ->> _) e = liftT $ Left $ ParseError (extrPos e)
 166                         "Expression cannot be a higher order function. Yet..."
 167         unify VoidType e = liftT $ Left $ ParseError (extrPos e)
 168                         "Expression cannot be a Void type."
 169 //      unify (IdType _) e = liftT $ Left $ ParseError (extrPos e)
 170 //                      "Expression cannot be an polymorf type."
 171     unify VarType e = typeExpr e
 172     //we have to cheat to decorate the error, can be done nicer?
 173     unify t e = StateT $ \s0 -> let res = runStateT m s0 in case res of
 174         Left err = Left $ decErr e err
 175         Right t = Right t //note, t :: (Type, Gamma)
 176     where m = typeExpr e >>= \tex-> unify t tex
 177
 178 instance unify Type where
 179         unify IntType IntType = pure IntType
 180         unify BoolType BoolType = pure BoolType
 181         unify CharType CharType = pure CharType
 182     unify (IdType i) t=:(IdType j) = replace i t >>| pure t
 183     unify t (IdType i) = unify (IdType i) t
 184     unify (IdType i) t = replace i t >>| pure t
 185     unify (ListType t1) (ListType t2) = unify t1 t2 >>| (pure $ ListType t1)
 186     unify (ta1 ->> ta2) (tb1 ->> tb2) = unify ta1 tb1 >>= \ta-> unify ta2 tb2
 187         >>= \tb-> pure (ta ->> tb)
 188         unify t1 t2 = liftT $ Left $ UnifyError zero t1 t2
 189
 190 instance zero Pos where
 191         zero = {line=0,col=0}
 192
 193 decErr :: Expr SemError -> SemError
 194 decErr e (UnifyError _ t1 t2) = UnifyError (extrPos e) t1 t2
 195 decErr e (FieldSelectorError _ t fs) = FieldSelectorError (extrPos e) t fs
 196 decErr e (ParseError _ s) = ParseError (extrPos e) s
 197 decErr e err = err
 198
 199 dc2 :: Expr (Either SemError a) -> Either SemError a
 200 dc2 e (Right t) = Right t
 201 dc2 e (Left err) = Left err
 202
 203 extrPos :: Expr -> Pos
 204 extrPos (VarExpr p _) = p
 205 extrPos (Op2Expr p _ _ _) = p
 206 extrPos (Op1Expr p _ _) = p
 207 extrPos (IntExpr p _) = p
 208 extrPos (CharExpr p _) = p
 209 extrPos (BoolExpr p _) = p
 210 extrPos (FunExpr p _) = p
 211 extrPos (EmptyListExpr p) = p
 212 extrPos (TupleExpr p _) = p
 213
 214 instance toString Gamma where
 215         toString (mp, _) = concat
 216                 [concat [k, ": ", toString v, "\n"]\\(k, v) <- 'Map'.toList mp]
 217
 218 getRandomStream :: Int -> [String]
 219 getRandomStream i = genIdents $ filter (isAlpha o toChar) (genRandInt i)
 220     where
 221         genIdents r = let (ic, r2) = splitAt 5 r in [toString ic: genIdents r2]
 222
 223 freshIdent :: Env String
 224 freshIdent = get >>= \(st, [ident:rest])-> put (st, rest)
 225     >>| case 'Map'.get ident st of
 226         Nothing = pure ident
 227         _       = freshIdent
 228
 229 putIdent :: String Type -> Env Void
 230 putIdent i t = gets (\(st, r)->'Map'.get i st) >>= \mt -> case mt of
 231     Nothing = modify (\(st, r)->('Map'.put i t st, r))
 232     Just t2 = unify t t2 >>= \t3-> modify (\(st, r)->('Map'.put i t3 st, r))
 233
 234 replace :: String Type -> Env Void
 235 replace ident type = get >>= \(st, fr)->put ('Map'.fromList $
 236         map (itupdate ident type) ('Map'.toList st), fr)
 237     where
 238         itupdate :: String Type (String, Type) -> (String, Type)
 239         itupdate ident newtype ov=:(key, IdType type) = if (ident == type)
 240             (key, newtype) ov
 241         itupdate ident newtype (key, TupleType (t1, t2))
 242         # (_, t1) = itupdate ident newtype (key, t1)
 243         # (_, t2) = itupdate ident newtype (key, t2)
 244         = (key, TupleType (t1, t2))
 245         itupdate ident newtype (key, ListType t1)
 246         # (_, t1) = itupdate ident newtype (key, t1)
 247         = (key, ListType t1)
 248         itupdate _ _ k = k
 249
 250 instance toString SemError where
 251     toString (ParseError p e) = concat [
 252         toString p,"SemError: ParseError: ", e]
 253     toString (Error e) = "SemError: " +++ e
 254     toString (UnifyError p t1 t2) = concat [
 255         toString p,
 256         "SemError: Cannot unify types. Expected: ",
 257         toString t1, ". Given: ", toString t2]
 258     toString (FieldSelectorError p t fs) = concat [
 259         toString p,
 260         "SemError: Cannot select ", toString fs, " from type: ",
 261         toString t]
 262     toString (OperatorError p o t) = concat [
 263         toString p,
 264         "SemError: No ", toString o, " for type ",
 265         toString t]
 266     toString (UndeclaredVariableError p ident) = concat [
 267         toString p, "SemError: identifier: ", ident, " undefined."]
 268
 269 saveGamma :: Env Gamma
 270 saveGamma = get
 271
 272 restoreGamma :: Gamma -> Env Void
 273 restoreGamma (oldstate, _) = gets snd >>= \newr->put (oldstate, newr)