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 (UnifyErrorStub t1 t2) = toString (UnifyError {line=0,col=0} t1 t2)
  56         toString (UnifyError p t1 t2) = concat [
  57                 toString p,
  58                 "SemError: Cannot unify types. Expected: ",
  59                 toString t1, ". Given: ", toString t2]
  60
  61 sem :: AST -> SemOutput
  62 sem (AST vd fd) = case evalStateT m ('Map'.newMap, getRandomStream 1) of
  63     Left e = Left [e]
  64     Right ((vds, fds), gamma) = Right ((AST vds fds), gamma)
  65 where
  66     m :: Env (([VarDecl], [FunDecl]))
  67     m = (mapM semVarDecl vd) >>= \vds ->
  68         mapM semFunDecl fd >>= \fds ->
  69         pure (vds, fds)
  70
  71 semFunDecl :: FunDecl -> Env FunDecl
  72 semFunDecl f = pure f
  73
  74 semVarDecl :: VarDecl -> Env VarDecl
  75 semVarDecl (VarDecl pos type ident ex) = unify type ex
  76     >>= \t-> putIdent ident t >>| (pure $ VarDecl pos t ident ex)
  77
  78 typeExpr :: Expr -> Env Type
  79 typeExpr (IntExpr _ _) = pure IntType
  80 typeExpr (CharExpr _ _) = pure CharType
  81 typeExpr (BoolExpr _ _) = pure BoolType
  82 typeExpr (Op1Expr p UnNegation expr) = unify BoolType expr
  83 typeExpr (Op1Expr p UnMinus expr) = unify IntType expr
  84 typeExpr (TupleExpr p (e1, e2)) = typeExpr e1
  85     >>= \t1-> typeExpr e2 >>= \t2-> pure $ TupleType (t1, t2)
  86 //Int
  87 typeExpr (Op2Expr p e1 BiPlus e2) = unify IntType e1 >>| unify IntType e2
  88 typeExpr (Op2Expr p e1 BiMinus e2) = unify IntType e1 >>| unify IntType e2
  89 typeExpr (Op2Expr p e1 BiTimes e2) = unify IntType e1 >>| unify IntType e2
  90 typeExpr (Op2Expr p e1 BiDivide e2) = unify IntType e1 >>| unify IntType e2
  91 typeExpr (Op2Expr p e1 BiMod e2) = unify IntType e1 >>| unify IntType e2
  92 //bool, char of int
  93 typeExpr (Op2Expr p e1 BiEquals e2) = typeExpr e1 >>= \t1 -> unify t1 e2
  94     >>| pure BoolType //todo, actually check t1 in Char,Bool,Int
  95 typeExpr (Op2Expr p e1 BiUnEqual e2) = typeExpr (Op2Expr p e1 BiEquals e2)
  96 //char of int
  97 typeExpr (Op2Expr p e1 BiLesser e2) = typeExpr e1 >>= \t1 -> unify t1 e2
  98     >>| pure BoolType //todo, actually check t1 in Char, Int
  99 typeExpr (Op2Expr p e1 BiGreater e2) = typeExpr (Op2Expr p e1 BiLesser e2)
 100 typeExpr (Op2Expr p e1 BiLesserEq e2) = typeExpr (Op2Expr p e1 BiLesser e2)
 101 typeExpr (Op2Expr p e1 BiGreaterEq e2) = typeExpr (Op2Expr p e1 BiLesser e2)
 102 //bool
 103 typeExpr (Op2Expr p e1 BiAnd e2) = unify BoolType e1 >>| unify BoolType e2
 104 typeExpr (Op2Expr p e1 BiOr e2) = unify BoolType e1 >>| unify BoolType e2
 105 //a
 106 typeExpr (Op2Expr p e1 BiCons e2) = typeExpr e1 >>= \t1-> typeExpr e2
 107     >>= \t2-> unify (ListType t1) t2
 108 typeExpr (EmptyListExpr p) = freshIdent >>= \frsh-> let t = IdType frsh in
 109     putIdent frsh t >>| pure t
 110 //typeExpr (FunExpr p FunCall) = undef
 111 //typeExpr (VarExpr Pos VarDef) = undef //when checking var-expr, be sure to
 112     //put the infered type in the context
 113
 114 class unify a :: Type a -> Env Type
 115
 116 instance unify Expr where
 117         unify (_ ->> _) e = liftT $ Left $ ParseError (extrPos e)
 118                         "Expression cannot be a higher order function. Yet..."
 119         unify VoidType e = liftT $ Left $ ParseError (extrPos e)
 120                         "Expression cannot be a Void type."
 121         unify (IdType _) e = liftT $ Left $ ParseError (extrPos e)
 122                         "Expression cannot be an polymorf type."
 123     unify VarType e = typeExpr e
 124     //we have to cheat to decorate the error, can be done nicer?
 125     unify t e = StateT $ \s0 -> let res = runStateT m s0 in case res of
 126         Left err = Left $ decErr e err
 127         Right t = Right t //note, t :: (Type, Gamma)
 128     where m = typeExpr e >>= \tex-> unify t tex
 129
 130 //unify e (IdType i) = unify (IdType i) e
 131     //note, don't use putIdent as that will call unify again
 132     //unify (IdType i) e=:(IdType j) = modify (\(st, r)->('Map'.put j e st, r))
 133
 134 instance unify Type where
 135         unify IntType IntType = pure IntType
 136         unify BoolType BoolType = pure BoolType
 137         unify CharType CharType = pure CharType
 138     //unify (ListType t1) (ListType t2) = unify t1 t2
 139         unify t1 t2 = liftT $ Left $ UnifyError zero t1 t2
 140
 141 instance zero Pos where
 142         zero = {line=0,col=0}
 143
 144 decErr :: Expr SemError -> SemError
 145 decErr e (UnifyError _ t1 t2) = UnifyError (extrPos e) t1 t2
 146 decErr e (ParseError _ s) = ParseError (extrPos e) s
 147 decErr e err = err
 148
 149 dc2 :: Expr (Either SemError a) -> Either SemError a
 150 dc2 e (Right t) = Right t
 151 dc2 e (Left err) = Left err
 152
 153 extrPos :: Expr -> Pos
 154 extrPos (VarExpr p _) = p
 155 extrPos (Op2Expr p _ _ _) = p
 156 extrPos (Op1Expr p _ _) = p
 157 extrPos (IntExpr p _) = p
 158 extrPos (CharExpr p _) = p
 159 extrPos (BoolExpr p _) = p
 160 extrPos (FunExpr p _) = p
 161 extrPos (EmptyListExpr p) = p
 162 extrPos (TupleExpr p _) = p
 163
 164 instance toString Gamma where
 165         toString (mp, _) = concat
 166                 [concat [k, ": ", toString v, "\n"]\\(k, v) <- 'Map'.toList mp]