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 (AssStmt (VarDef ident fs) e) = undef
  96 checkStmt t r=:(FunStmt (FunCall f es)) = typeFun f es >>| pure r
  97 checkStmt VoidType r=:(ReturnStmt Nothing) = pure r
  98 checkStmt t r=:(ReturnStmt (Just e)) = unify t e >>| pure r
  99
 100 typeExpr :: Expr -> Env Type
 101 typeExpr (IntExpr _ _) = pure IntType
 102 typeExpr (CharExpr _ _) = pure CharType
 103 typeExpr (BoolExpr _ _) = pure BoolType
 104 typeExpr (Op1Expr p UnNegation expr) = unify BoolType expr
 105 typeExpr (Op1Expr p UnMinus expr) = unify IntType expr
 106 typeExpr (TupleExpr p (e1, e2)) = typeExpr e1
 107     >>= \t1-> typeExpr e2 >>= \t2-> pure $ TupleType (t1, t2)
 108 typeExpr (Op2Expr p e1 op e2)
 109 | isMember op [BiPlus, BiMinus, BiTimes, BiDivide, BiMod] =
 110         typeOp2 e1 e2 op [IntType] IntType
 111 | isMember op [BiEquals, BiUnEqual] =
 112         typeOp2 e1 e2 op [IntType, BoolType, CharType] BoolType
 113 | isMember op [BiLesser, BiGreater, BiLesserEq, BiGreaterEq] =
 114         typeOp2 e1 e2 op [IntType, CharType] BoolType
 115 | isMember op [BiAnd, BiOr] =
 116         typeOp2 e1 e2 op [BoolType] BoolType
 117 | op == BiCons = typeExpr e1 >>= \t1-> typeExpr e2
 118         >>= \t2-> unify (ListType t1) t2
 119 typeExpr (EmptyListExpr p) = freshIdent >>= \frsh-> let t = IdType frsh in
 120     putIdent frsh t >>| pure t
 121 typeExpr (FunExpr p (FunCall f es)) = typeFun f es
 122 typeExpr (VarExpr p (VarDef ident fs)) = gets (\(st, r)->'Map'.get ident st)
 123     >>= \mt->case mt of
 124         Nothing = liftT $ Left $ UndeclaredVariableError p ident
 125         Just t = unify t fs
 126
 127 typeOp2 :: Expr Expr Op2 [Type] Type -> Env Type
 128 typeOp2 e1 e2 op ts ret = typeExpr e1 >>= \t1-> typeExpr e2 >>= \t2->
 129     unify t1 t2 >>= \t3->if (isMember t3 ts) (pure ret)
 130         (liftT $ Left $ OperatorError (extrPos e1) op t3)
 131
 132 buildFunctionType :: String [Expr] -> Env Type
 133 buildFunctionType frsh [] = let t = IdType frsh in putIdent frsh t >>| pure t
 134 buildFunctionType frsh [e:es] = (->>) <$> typeExpr e <*> buildFunctionType frsh es
 135
 136 unifyApp :: Type [Expr] -> Env Type
 137 unifyApp t [] = pure t
 138 unifyApp (tf1 ->> tf2) [t1:ts] = unify tf1 t1 >>| unifyApp tf2 ts
 139 unifyApp t1 t2 = liftT $ Left $ UnifyError zero t1 (IdType "[expressions, FIXME]")
 140
 141 typeFun :: String [Expr] -> Env Type
 142 typeFun f es = gets (\(st, r)->'Map'.get f st) >>= \mt-> case mt of
 143     Nothing = freshIdent >>= \frsh-> buildFunctionType frsh es
 144         >>= \ft-> putIdent f ft >>| (pure $ IdType frsh)
 145     Just t = unifyApp t es
 146
 147 resultType :: Type -> Type
 148 resultType (_ ->> t) = resultType t
 149 resultType t = t
 150
 151 class unify a :: Type a -> Env Type
 152
 153 instance unify [FieldSelector] where
 154     unify t [] = pure t
 155     unify (ListType t) [FieldHd:fs] = unify t fs
 156     unify t=:(ListType _) [FieldTl:fs] = unify t fs
 157     unify (TupleType (t, _)) [FieldFst:fs] = unify t fs
 158     unify (TupleType (_, t)) [FieldSnd:fs] = unify t fs
 159     unify t [fs:_] = liftT $ Left $ FieldSelectorError zero t fs
 160
 161 instance unify Expr where
 162         unify (_ ->> _) e = liftT $ Left $ ParseError (extrPos e)
 163                         "Expression cannot be a higher order function. Yet..."
 164         unify VoidType e = liftT $ Left $ ParseError (extrPos e)
 165                         "Expression cannot be a Void type."
 166 //      unify (IdType _) e = liftT $ Left $ ParseError (extrPos e)
 167 //                      "Expression cannot be an polymorf type."
 168     unify VarType e = typeExpr e
 169     //we have to cheat to decorate the error, can be done nicer?
 170     unify t e = StateT $ \s0 -> let res = runStateT m s0 in case res of
 171         Left err = Left $ decErr e err
 172         Right t = Right t //note, t :: (Type, Gamma)
 173     where m = typeExpr e >>= \tex-> unify t tex
 174
 175 instance unify Type where
 176         unify IntType IntType = pure IntType
 177         unify BoolType BoolType = pure BoolType
 178         unify CharType CharType = pure CharType
 179     unify (IdType i) t=:(IdType j) = replace i t >>| pure t
 180     unify t (IdType i) = unify (IdType i) t
 181     unify (IdType i) t = replace i t >>| pure t
 182     unify (ListType t1) (ListType t2) = unify t1 t2 >>| (pure $ ListType t1)
 183     unify (ta1 ->> ta2) (tb1 ->> tb2) = unify ta1 tb1 >>= \ta-> unify ta2 tb2
 184         >>= \tb-> pure (ta ->> tb)
 185         unify t1 t2 = liftT $ Left $ UnifyError zero t1 t2
 186
 187 instance zero Pos where
 188         zero = {line=0,col=0}
 189
 190 decErr :: Expr SemError -> SemError
 191 decErr e (UnifyError _ t1 t2) = UnifyError (extrPos e) t1 t2
 192 decErr e (FieldSelectorError _ t fs) = FieldSelectorError (extrPos e) t fs
 193 decErr e (ParseError _ s) = ParseError (extrPos e) s
 194 decErr e err = err
 195
 196 dc2 :: Expr (Either SemError a) -> Either SemError a
 197 dc2 e (Right t) = Right t
 198 dc2 e (Left err) = Left err
 199
 200 extrPos :: Expr -> Pos
 201 extrPos (VarExpr p _) = p
 202 extrPos (Op2Expr p _ _ _) = p
 203 extrPos (Op1Expr p _ _) = p
 204 extrPos (IntExpr p _) = p
 205 extrPos (CharExpr p _) = p
 206 extrPos (BoolExpr p _) = p
 207 extrPos (FunExpr p _) = p
 208 extrPos (EmptyListExpr p) = p
 209 extrPos (TupleExpr p _) = p
 210
 211 instance toString Gamma where
 212         toString (mp, _) = concat
 213                 [concat [k, ": ", toString v, "\n"]\\(k, v) <- 'Map'.toList mp]
 214
 215 getRandomStream :: Int -> [String]
 216 getRandomStream i = genIdents $ filter (isAlpha o toChar) (genRandInt i)
 217     where
 218         genIdents r = let (ic, r2) = splitAt 5 r in [toString ic: genIdents r2]
 219
 220 freshIdent :: Env String
 221 freshIdent = get >>= \(st, [ident:rest])-> put (st, rest)
 222     >>| case 'Map'.get ident st of
 223         Nothing = pure ident
 224         _       = freshIdent
 225
 226 putIdent :: String Type -> Env Void
 227 putIdent i t = gets (\(st, r)->'Map'.get i st) >>= \mt -> case mt of
 228     Nothing = modify (\(st, r)->('Map'.put i t st, r))
 229     Just t2 = unify t t2 >>= \t3-> modify (\(st, r)->('Map'.put i t3 st, r))
 230
 231 replace :: String Type -> Env Void
 232 replace ident type = get >>= \(st, fr)->put ('Map'.fromList $
 233         map (itupdate ident type) ('Map'.toList st), fr)
 234     where
 235         itupdate :: String Type (String, Type) -> (String, Type)
 236         itupdate ident newtype ov=:(key, IdType type) = if (ident == type)
 237             (key, newtype) ov
 238         itupdate ident newtype (key, TupleType (t1, t2))
 239         # (_, t1) = itupdate ident newtype (key, t1)
 240         # (_, t2) = itupdate ident newtype (key, t2)
 241         = (key, TupleType (t1, t2))
 242         itupdate ident newtype (key, ListType t1)
 243         # (_, t1) = itupdate ident newtype (key, t1)
 244         = (key, ListType t1)
 245         itupdate _ _ k = k
 246
 247 instance toString SemError where
 248     toString (ParseError p e) = concat [
 249         toString p,"SemError: ParseError: ", e]
 250     toString (Error e) = "SemError: " +++ e
 251     toString (UnifyError p t1 t2) = concat [
 252         toString p,
 253         "SemError: Cannot unify types. Expected: ",
 254         toString t1, ". Given: ", toString t2]
 255     toString (FieldSelectorError p t fs) = concat [
 256         toString p,
 257         "SemError: Cannot select ", toString fs, " from type: ",
 258         toString t]
 259     toString (OperatorError p o t) = concat [
 260         toString p,
 261         "SemError: No ", toString o, " for type ",
 262         toString t]
 263     toString (UndeclaredVariableError p ident) = concat [
 264         toString p, "SemError: identifier: ", ident, " undefined."]
 265
 266 saveGamma :: Env Gamma
 267 saveGamma = get
 268
 269 restoreGamma :: Gamma -> Env Void
 270 restoreGamma (oldstate, _) = gets snd >>= \newr->put (oldstate, newr)