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 StdMisc
  14 from StdFunc import id, const, o
  15 import StdString
  16 import StdTuple
  17 import StdList
  18
  19 from Text import class Text(concat), instance Text String
  20
  21 import AST
  22 from parse import :: ParserOutput, :: Error
  23
  24 :: Gamma :== ('Map'.Map String Type, [String])
  25 :: Env a :== (State Gamma (Either SemError a))
  26
  27 get = state $ \s -> (s,s)
  28
  29 getRandomStream :: Int -> [String]
  30 getRandomStream i = genIdents $ filter (isAlpha o toChar) (genRandInt i)
  31         where
  32                 genIdents r = let (ic, r) = splitAt 5 r in [toString ic: genIdents r]
  33
  34 freshIdent :: Gamma -> (String, Gamma)
  35 freshIdent (st, [ident:rest]) = case 'Map'.get ident st of
  36         Nothing = (ident, (st, rest))
  37         _ = freshIdent (st, rest)
  38
  39 putIdent :: String Type -> Env Void
  40 putIdent i t = gets (\(st, r)->'Map'.get i st) >>= \mt -> case mt of
  41     Nothing = pure <$> modify (\(st, r)->('Map'.put i t st, r))
  42     Just t2 = unify t t2 >>= \r -> case r of
  43         Left e  = pure $ Left e
  44         Right t3 = pure <$> modify (\(st, r)->('Map'.put i t3 st, r))
  45
  46 instance toString SemError where
  47         toString (ParseError p e) = concat [
  48                 toString p,"SemError: ParseError: ", e]
  49         toString (Error e) = "SemError: " +++ e
  50         toString (UnifyErrorStub t1 t2) = toString (UnifyError {line=0,col=0} t1 t2)
  51         toString (UnifyError p t1 t2) = concat [
  52                 toString p,
  53                 "SemError: Cannot unify types. Expected: ",
  54                 toString t1, ". Given: ", toString t2]
  55
  56 sem :: AST -> SemOutput
  57 sem (AST vd fd)
  58 # (eithervds, gamma) = runState (mapM semVarDecl vd) ('Map'.newMap, getRandomStream 0)
  59 # (eitherfds, gamma) = runState (mapM semFunDecl fd) gamma
  60 = case splitEithers eithervds of
  61         (Left errs) = Left $ errs ++ [x\\(Left x)<-eitherfds]
  62         (Right vds) = case splitEithers eitherfds of
  63                 (Left errs) = Left errs
  64                 (Right fds) = Right $ AST vds fds
  65
  66 splitEithers :: [Either a b] -> Either [a] [b]
  67 splitEithers [] = Right []
  68 splitEithers [Right x:xs] = splitEithers xs >>= \rest->Right [x:rest]
  69 splitEithers xs = Left $ [x\\(Left x)<-xs]
  70
  71 semFunDecl :: FunDecl -> Env FunDecl
  72 semFunDecl f = pure $ Right f
  73
  74 semVarDecl :: VarDecl -> Env VarDecl
  75 semVarDecl vd=:(VarDecl pos type ident ex) = unify type ex
  76         >>= \et->case et of
  77                 Left err = pure $ Left err
  78                 Right t = putIdent ident t >>| pure (Right $ VarDecl pos t ident ex)
  79
  80 typeExpr :: Expr -> Env Type
  81 typeExpr (IntExpr _ _) = pure $ Right IntType
  82 typeExpr (CharExpr _ _) = pure $ Right CharType
  83 typeExpr (BoolExpr _ _) = pure $ Right BoolType
  84 typeExpr (Op1Expr p UnNegation expr) = unify BoolType expr
  85 typeExpr (Op1Expr p UnMinus expr) = unify IntType expr
  86 typeExpr (TupleExpr p (e1, e2)) = typeExpr e1
  87         >>= \ete1->typeExpr e2 >>= \ete2->pure (
  88                 ete1 >>= \te1->ete2 >>= \te2->Right $ TupleType (te1, te2))
  89 //Int
  90 typeExpr (Op2Expr p e1 BiPlus e2) = unify IntType e1 >>| unify IntType e2
  91 typeExpr (Op2Expr p e1 BiMinus e2) = unify IntType e1 >>| unify IntType e2
  92 typeExpr (Op2Expr p e1 BiTimes e2) = unify IntType e1 >>| unify IntType e2
  93 typeExpr (Op2Expr p e1 BiDivide e2) = unify IntType e1 >>| unify IntType e2
  94 typeExpr (Op2Expr p e1 BiMod e2) = unify IntType e1 >>| unify IntType e2
  95 //bool, char of int
  96 typeExpr (Op2Expr p e1 BiEquals e2) = undef
  97 typeExpr (Op2Expr p e1 BiUnEqual e2) = undef
  98 //char of int
  99 typeExpr (Op2Expr p e1 BiLesser e2) = undef
 100 typeExpr (Op2Expr p e1 BiGreater e2) = undef
 101 typeExpr (Op2Expr p e1 BiLesserEq e2) = undef
 102 typeExpr (Op2Expr p e1 BiGreaterEq e2) = undef
 103 //bool
 104 typeExpr (Op2Expr p e1 BiAnd e2) = undef
 105 typeExpr (Op2Expr p e1 BiOr e2) = undef
 106 //a
 107 typeExpr (Op2Expr p e1 BiCons e2) = undef
 108 //typeExpr (FunExpr Pos FunCall) = undef
 109 //typeExpr (EmptyListExpr Pos) = undef
 110 //typeExpr (VarExpr Pos VarDef) = undef //when checking var-expr, be sure to
 111 //put the infered type
 112                                         //in the context
 113
 114 class unify a :: Type a -> Env Type
 115
 116 instance unify Expr where
 117         unify (_ ->> _) e = pure $ Left $ ParseError (extrPos e)
 118                         "Expression cannot be a higher order function. Yet..."
 119         unify VoidType e = pure $ Left $ ParseError (extrPos e)
 120                         "Expression cannot be a Void type."
 121         unify (IdType _) e = pure $ Left $ ParseError (extrPos e)
 122                         "Expression cannot be an polymorf type."
 123     unify VarType e = typeExpr e
 124         unify t e = typeExpr e
 125                 >>= \eithertype->case eithertype of
 126                         Left e = pure $ Left e
 127                         Right tex = unify t tex >>= \eitherun->case eitherun of
 128                                 Left err = pure $ Left $ decErr e err
 129                                 Right t = pure $ Right t
 130
 131 instance unify Type where
 132         unify IntType IntType = pure $ Right IntType
 133         unify BoolType BoolType = pure $ Right BoolType
 134         unify CharType CharType = pure $ Right CharType
 135         unify t1 t2 = pure $ Left $ UnifyError zero t1 t2
 136
 137 instance zero Pos where
 138         zero = {line=0,col=0}
 139
 140 decErr :: Expr SemError -> SemError
 141 decErr e (UnifyError _ t1 t2) = UnifyError (extrPos e) t1 t2
 142 decErr e (ParseError _ s) = ParseError (extrPos e) s
 143 decErr e err = err
 144
 145 extrPos :: Expr -> Pos
 146 extrPos (VarExpr p _) = p
 147 extrPos (Op2Expr p _ _ _) = p
 148 extrPos (Op1Expr p _ _) = p
 149 extrPos (IntExpr p _) = p
 150 extrPos (CharExpr p _) = p
 151 extrPos (BoolExpr p _) = p
 152 extrPos (FunExpr p _) = p
 153 extrPos (EmptyListExpr p) = p
 154 extrPos (TupleExpr p _) = p