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 StdMisc
  13 from StdFunc import id, const
  14 import StdString
  15 import StdList
  16
  17 from Text import class Text(concat), instance Text String
  18
  19 import AST
  20 from parse import :: ParserOutput, :: Error
  21
  22 :: Gamma :== 'Map'.Map String Type
  23 :: Env a :== (State Gamma (Either SemError a))
  24
  25 get = state $ \s -> (s,s)
  26
  27 putIdent :: String Type -> Env Void
  28 putIdent i t = gets ('Map'.get i) >>= \mt -> case mt of
  29     Nothing = pure <$> modify ('Map'.put i t)
  30     Just t2 = unify t t2 >>= \r -> case r of
  31         Left e  = pure $ Left e
  32         Right t3 = pure <$> modify ('Map'.put i t3)
  33
  34 instance toString SemError where
  35         toString (ParseError p e) = concat [
  36                 toString p,"SemError: ParseError: ", e]
  37         toString (Error e) = "SemError: " +++ e
  38         toString (UnifyErrorStub t1 t2) = toString (UnifyError {line=0,col=0} t1 t2)
  39         toString (UnifyError p t1 t2) = concat [
  40                 toString p,
  41                 "SemError: Cannot unify types. Expected: ",
  42                 toString t1, ". Given: ", toString t2]
  43
  44 sem :: AST -> SemOutput
  45 sem (AST vd fd)
  46 # (eithervds, gamma) = runState (mapM semVarDecl vd) 'Map'.newMap
  47 # (eitherfds, gamma) = runState (mapM semFunDecl fd) gamma
  48 = case splitEithers eithervds of
  49         (Left errs) = Left $ errs ++ [x\\(Left x)<-eitherfds]
  50         (Right vds) = case splitEithers eitherfds of
  51                 (Left errs) = Left errs
  52                 (Right fds) = Right $ AST vds fds
  53
  54 splitEithers :: [Either a b] -> Either [a] [b]
  55 splitEithers [] = Right []
  56 splitEithers [Right x:xs] = splitEithers xs >>= \rest->Right [x:rest]
  57 splitEithers xs = Left $ [x\\(Left x)<-xs]
  58
  59 semFunDecl :: FunDecl -> Env FunDecl
  60 semFunDecl f = pure $ Right f
  61
  62 semVarDecl :: VarDecl -> Env VarDecl
  63 semVarDecl vd=:(VarDecl pos type ident ex) = unify type ex
  64         >>= \et->case et of
  65                 Left err = pure $ Left err
  66                 Right t = putIdent ident t >>| pure (Right $ VarDecl pos t ident ex)
  67 //Right v
  68 //      //TODO ident in de environment
  69 //      Right e = Right $ pure vd
  70
  71 typeExpr :: Expr -> Env Type
  72 typeExpr (IntExpr _ _) = pure $ Right IntType
  73 typeExpr (CharExpr _ _) = pure $ Right CharType
  74 typeExpr (BoolExpr _ _) = pure $ Right BoolType
  75 typeExpr (Op1Expr p UnNegation expr) = unify BoolType expr
  76 typeExpr (Op1Expr p UnMinus expr) = unify IntType expr
  77 typeExpr (TupleExpr p (e1, e2)) = typeExpr e1
  78         >>= \ete1->typeExpr e2 >>= \ete2->pure (
  79                 ete1 >>= \te1->ete2 >>= \te2->Right $ TupleType (te1, te2))
  80 //typeExpr (Op2Expr Pos Expr Op2 Expr) = undef
  81 //typeExpr (FunExpr Pos FunCall) = undef
  82 //typeExpr (EmptyListExpr Pos) = undef
  83 //typeExpr (VarExpr Pos VarDef) = undef
  84
  85 class unify a :: Type a -> Env Type
  86
  87 instance unify Expr where
  88         unify (_ ->> _) e = pure $ Left $ ParseError (extrPos e)
  89                         "Expression cannot be a higher order function. Yet..."
  90         unify VoidType e = pure $ Left $ ParseError (extrPos e)
  91                         "Expression cannot be a Void type."
  92         unify (IdType _) e = pure $ Left $ ParseError (extrPos e)
  93                         "Expression cannot be an polymorf type."
  94         unify t e = typeExpr e
  95                 >>= \eithertype->case eithertype of
  96                         Left e = pure $ Left e
  97                         Right tex = unify t tex >>= \eitherun->case eitherun of
  98                                 Left err = pure $ Left $ decErr e err
  99                                 Right t = pure $ Right t
 100
 101 instance unify Type where
 102         unify IntType IntType = pure $ Right IntType
 103         unify BoolType BoolType = pure $ Right BoolType
 104         unify CharType CharType = pure $ Right CharType
 105         unify t1 t2 = pure $ Left $ UnifyError zero t1 t2
 106
 107 instance zero Pos where
 108         zero = {line=0,col=0}
 109
 110 decErr :: Expr SemError -> SemError
 111 decErr e (UnifyError _ t1 t2) = UnifyError (extrPos e) t1 t2
 112 decErr e (ParseError _ s) = ParseError (extrPos e) s
 113 decErr e err = err
 114
 115 extrPos :: Expr -> Pos
 116 extrPos (VarExpr p _) = p
 117 extrPos (Op2Expr p _ _ _) = p
 118 extrPos (Op1Expr p _ _) = p
 119 extrPos (IntExpr p _) = p
 120 extrPos (CharExpr p _) = p
 121 extrPos (BoolExpr p _) = p
 122 extrPos (FunExpr p _) = p
 123 extrPos (EmptyListExpr p) = p
 124 extrPos (TupleExpr p _) = p