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