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
  20 from Text import class Text(concat), instance Text String
  21
  22 import AST
  23 from parse import :: ParserOutput, :: Error
  24
  25 :: Gamma :== ('Map'.Map String Type, [String])
  26 :: Env a :== StateT Gamma (Either SemError) a
  27 //StateT (Gamma -> Either SemError (a, Gamma))
  28
  29 //we need to redefine this even though it is in Control.Monad.State
  30 instance MonadTrans (StateT Gamma) where
  31     liftT m = StateT \s-> m >>= \a-> return (a, s)
  32
  33 get = gets id
  34
  35 getRandomStream :: Int -> [String]
  36 getRandomStream i = genIdents $ filter (isAlpha o toChar) (genRandInt i)
  37         where
  38                 genIdents r = let (ic, r2) = splitAt 5 r in [toString ic: genIdents r2]
  39
  40 freshIdent :: Env String
  41 freshIdent = get >>= \(st, [ident:rest])-> put (st, rest)
  42     >>| case 'Map'.get ident st of
  43         Nothing = pure ident
  44         _       = freshIdent
  45
  46 putIdent :: String Type -> Env Void
  47 putIdent i t = gets (\(st, r)->'Map'.get i st) >>= \mt -> case mt of
  48     Nothing = modify (\(st, r)->('Map'.put i t st, r))
  49     Just t2 = unify t t2 >>= \t3-> modify (\(st, r)->('Map'.put i t3 st, r))
  50
  51 instance toString SemError where
  52         toString (ParseError p e) = concat [
  53                 toString p,"SemError: ParseError: ", e]
  54         toString (Error e) = "SemError: " +++ e
  55         toString (UnifyError p t1 t2) = concat [
  56                 toString p,
  57                 "SemError: Cannot unify types. Expected: ",
  58                 toString t1, ". Given: ", toString t2]
  59     toString (FieldSelectorError p t fs) = concat [
  60         toString p,
  61         "SemError: Cannot select ", toString fs, " from type: ",
  62         toString t]
  63         toString (OperatorError p o t) = concat [
  64                 toString p,
  65                 "SemError: No ", toString o, " for type ",
  66                 toString t]
  67
  68 sem :: AST -> SemOutput
  69 sem (AST vd fd) = case runStateT m ('Map'.newMap, getRandomStream 1) of
  70     Left e = Left [e]
  71     Right ((vds, fds), gamma) = Right ((AST vds fds), gamma)
  72 where
  73     m :: Env ([VarDecl], [FunDecl])
  74     m = (mapM semVarDecl vd) >>= \vds ->
  75         mapM semFunDecl fd >>= \fds ->
  76         pure (vds, fds)
  77
  78 semFunDecl :: FunDecl -> Env FunDecl
  79 semFunDecl f = pure f
  80
  81 semVarDecl :: VarDecl -> Env VarDecl
  82 semVarDecl (VarDecl pos type ident ex) = unify type ex
  83     >>= \t-> putIdent ident t >>| (pure $ VarDecl pos t ident ex)
  84
  85 typeOp2 :: Expr Expr Op2 [Type] -> Env Type
  86 typeOp2 e1 e2 op ts = typeExpr e1 >>= \t1-> typeExpr e2 >>= \t2->
  87         unify t1 t2     >>= \t3->if (isMember t3 ts) (pure t3)
  88                 (liftT $ Left $ OperatorError (extrPos e1) op t3)
  89
  90 typeExpr :: Expr -> Env Type
  91 typeExpr (IntExpr _ _) = pure IntType
  92 typeExpr (CharExpr _ _) = pure CharType
  93 typeExpr (BoolExpr _ _) = pure BoolType
  94 typeExpr (Op1Expr p UnNegation expr) = unify BoolType expr
  95 typeExpr (Op1Expr p UnMinus expr) = unify IntType expr
  96 typeExpr (TupleExpr p (e1, e2)) = typeExpr e1
  97     >>= \t1-> typeExpr e2 >>= \t2-> pure $ TupleType (t1, t2)
  98 typeExpr (Op2Expr p e1 op e2)
  99 | isMember op [BiPlus, BiMinus, BiTimes, BiDivide, BiMod] =
 100         typeOp2 e1 e2 op [IntType]
 101 | isMember op [BiEquals, BiUnEqual] =
 102         typeOp2 e1 e2 op [IntType, BoolType, CharType]
 103 | isMember op [BiLesser, BiGreater, BiLesserEq, BiGreaterEq] =
 104         typeOp2 e1 e2 op [IntType, CharType]
 105 | isMember op [BiAnd, BiOr] =
 106         typeOp2 e1 e2 op [BoolType]
 107 | op == BiCons = typeExpr e1 >>= \t1-> typeExpr e2
 108         >>= \t2-> unify (ListType t1) t2
 109 typeExpr (EmptyListExpr p) = freshIdent >>= \frsh-> let t = IdType frsh in
 110     putIdent frsh t >>| pure t
 111 typeExpr (FunExpr p (FunCall fid args)) = undef
 112 //ignore field selectors
 113 typeExpr (VarExpr p (VarDef ident fs)) = gets (\(st, r)->'Map'.get ident st)
 114         >>= \mt->case mt of
 115             Nothing = let t = IdType ident in putIdent ident t >>| pure t
 116             Just t = unify t fs
 117
 118 class unify a :: Type a -> Env Type
 119
 120 instance unify [FieldSelector] where
 121     unify t [] = pure t
 122     unify (ListType t) [FieldHd:fs] = unify t fs
 123     unify t=:(ListType _) [FieldTl:fs] = unify t fs
 124     unify (TupleType (t, _)) [FieldFst:fs] = unify t fs
 125     unify (TupleType (_, t)) [FieldSnd:fs] = unify t fs
 126     unify t [fs:_] = liftT $ Left $ FieldSelectorError zero t fs
 127
 128 instance unify Expr where
 129         unify (_ ->> _) e = liftT $ Left $ ParseError (extrPos e)
 130                         "Expression cannot be a higher order function. Yet..."
 131         unify VoidType e = liftT $ Left $ ParseError (extrPos e)
 132                         "Expression cannot be a Void type."
 133         unify (IdType _) e = liftT $ Left $ ParseError (extrPos e)
 134                         "Expression cannot be an polymorf type."
 135     unify VarType e = typeExpr e
 136     unify (IdType i) e = undef
 137     //we have to cheat to decorate the error, can be done nicer?
 138     unify t e = StateT $ \s0 -> let res = runStateT m s0 in case res of
 139         Left err = Left $ decErr e err
 140         Right t = Right t //note, t :: (Type, Gamma)
 141     where m = typeExpr e >>= \tex-> unify t tex
 142
 143 replace :: String Type -> Env Void
 144 replace ident type = get >>= \(st, fr)->put ('Map'.fromList $
 145                 map (itupdate ident type) ('Map'.toList st), fr)
 146         where
 147                 itupdate :: String Type (String, Type) -> (String, Type)
 148                 itupdate ident newtype ov=:(key, IdType type) = if (ident == type)
 149                         (key, newtype) ov
 150                 itupdate ident newtype (key, TupleType (t1, t2))
 151                 # (_, t1) = itupdate ident newtype (key, t1)
 152                 # (_, t2) = itupdate ident newtype (key, t2)
 153                 = (key, TupleType (t1, t2))
 154                 itupdate ident newtype (key, ListType t1)
 155                 # (_, t1) = itupdate ident newtype (key, t1)
 156                 = (key, ListType t1)
 157                 itupdate _ _ k = k
 158
 159 instance unify Type where
 160         unify IntType IntType = pure IntType
 161         unify BoolType BoolType = pure BoolType
 162         unify CharType CharType = pure CharType
 163     unify (IdType i) t=:(IdType j) = replace i t >>| pure t
 164     unify t (IdType i) = unify (IdType i) t
 165     unify (IdType i) t = replace i t >>| pure t
 166     unify (ListType t1) (ListType t2) = unify t1 t2 >>| (pure $ ListType t1)
 167         unify t1 t2 = liftT $ Left $ UnifyError zero t1 t2
 168
 169 instance zero Pos where
 170         zero = {line=0,col=0}
 171
 172 decErr :: Expr SemError -> SemError
 173 decErr e (UnifyError _ t1 t2) = UnifyError (extrPos e) t1 t2
 174 decErr e (FieldSelectorError _ t fs) = FieldSelectorError (extrPos e) t fs
 175 decErr e (ParseError _ s) = ParseError (extrPos e) s
 176 decErr e err = err
 177
 178 dc2 :: Expr (Either SemError a) -> Either SemError a
 179 dc2 e (Right t) = Right t
 180 dc2 e (Left err) = Left err
 181
 182 extrPos :: Expr -> Pos
 183 extrPos (VarExpr p _) = p
 184 extrPos (Op2Expr p _ _ _) = p
 185 extrPos (Op1Expr p _ _) = p
 186 extrPos (IntExpr p _) = p
 187 extrPos (CharExpr p _) = p
 188 extrPos (BoolExpr p _) = p
 189 extrPos (FunExpr p _) = p
 190 extrPos (EmptyListExpr p) = p
 191 extrPos (TupleExpr p _) = p
 192
 193 instance toString Gamma where
 194         toString (mp, _) = concat
 195                 [concat [k, ": ", toString v, "\n"]\\(k, v) <- 'Map'.toList mp]
 196
 197
 198 // class free a :: a -> Env [a]