import qualified Data.Map as Map
from Data.Func import $
+import Data.Maybe
import Data.Either
+import Data.Functor
+import Control.Applicative
+import Control.Monad
import Control.Monad.State
+import Control.Monad.Identity
+import Control.Monad.Trans
import StdMisc
+from StdFunc import id, const
+import StdString
+import StdList
+
+from Text import class Text(concat), instance Text String
import AST
-from parse import :: ParserOutput
-from yard import :: Error
+from parse import :: ParserOutput, :: Error
:: Gamma :== 'Map'.Map String Type
-:: Env a :== State Gamma a
+:: Env a :== StateT Gamma (Either SemError) a
+
+//we need to redefine this even though it is in Control.Monad.State
+instance MonadTrans (StateT Gamma) where
+ liftT m = StateT \s-> m >>= \a-> return (a, s)
+
+get = gets id
+
+instance toString SemError where
+ toString (ParseError p e) = concat [
+ toString p,"SemError: ParseError: ", e]
+ toString (Error e) = "SemError: " +++ e
+ toString (UnifyErrorStub t1 t2) = toString (UnifyError {line=0,col=0} t1 t2)
+ toString (UnifyError p t1 t2) = concat [
+ toString p,
+ "SemError: Cannot unify types. Expected: ",
+ toString t1, ". Given: ", toString t2]
+
+putIdent :: String Type -> Env Void
+putIdent i t = gets ('Map'.get i) >>= \mt -> case mt of
+ Nothing = modify ('Map'.put i t)
+ Just t2 = unify t t2 >>= \t3-> modify ('Map'.put i t3)
+
+sem :: AST -> SemOutput
+sem (AST vd fd) = case evalStateT m 'Map'.newMap of
+ Left e = Left [e]
+ Right (vds, fds) = Right (AST vds fds)
+where
+ m :: Env (([VarDecl], [FunDecl]))
+ m = (mapM semVarDecl vd) >>= \vds ->
+ mapM semFunDecl fd >>= \fds ->
+ pure (vds, fds)
+
+splitEithers :: [Either a b] -> Either [a] [b]
+splitEithers [] = Right []
+splitEithers [Right x:xs] = splitEithers xs >>= \rest->Right [x:rest]
+splitEithers xs = Left $ [x\\(Left x)<-xs]
-sem :: ParserOutput -> SemOutput
-sem (Left p) = Left p
-sem (Right (AST vd fd)) = Right $ AST vd fd
-// foldM semVarDecl vd
-// >>= \gamma ->foldM typecheck gamma fd
+semFunDecl :: FunDecl -> Env FunDecl
+semFunDecl f = pure f
semVarDecl :: VarDecl -> Env VarDecl
-semVarDecl (Vardecl pos type ident expr) = undef
-
+semVarDecl (VarDecl pos type ident ex) = unify type ex
+ >>= \t-> putIdent ident t >>| (pure $ VarDecl pos t ident ex)
+
+typeExpr :: Expr -> Env Type
+typeExpr (IntExpr _ _) = pure IntType
+typeExpr (CharExpr _ _) = pure CharType
+typeExpr (BoolExpr _ _) = pure BoolType
+typeExpr (Op1Expr p UnNegation expr) = unify BoolType expr
+typeExpr (Op1Expr p UnMinus expr) = unify IntType expr
+typeExpr (TupleExpr p (e1, e2)) = typeExpr e1
+ >>= \t1-> typeExpr e2 >>= \t2-> pure $ TupleType (t1, t2)
+//Int
+typeExpr (Op2Expr p e1 BiPlus e2) = unify IntType e1 >>| unify IntType e2
+typeExpr (Op2Expr p e1 BiMinus e2) = unify IntType e1 >>| unify IntType e2
+typeExpr (Op2Expr p e1 BiTimes e2) = unify IntType e1 >>| unify IntType e2
+typeExpr (Op2Expr p e1 BiDivide e2) = unify IntType e1 >>| unify IntType e2
+typeExpr (Op2Expr p e1 BiMod e2) = unify IntType e1 >>| unify IntType e2
+//bool, char of int
+typeExpr (Op2Expr p e1 BiEquals e2) = undef
+typeExpr (Op2Expr p e1 BiUnEqual e2) = undef
+//char of int
+typeExpr (Op2Expr p e1 BiLesser e2) = undef
+typeExpr (Op2Expr p e1 BiGreater e2) = undef
+typeExpr (Op2Expr p e1 BiLesserEq e2) = undef
+typeExpr (Op2Expr p e1 BiGreaterEq e2) = undef
+//bool
+typeExpr (Op2Expr p e1 BiAnd e2) = undef
+typeExpr (Op2Expr p e1 BiOr e2) = undef
+//a
+typeExpr (Op2Expr p e1 BiCons e2) = undef
+//typeExpr (FunExpr Pos FunCall) = undef
+//typeExpr (EmptyListExpr Pos) = undef
+//typeExpr (VarExpr Pos VarDef) = undef //when checking var-expr, be sure to put the infered type
+ //in the context
+
+class unify a :: Type a -> Env Type
+
+instance unify Expr where
+ unify (_ ->> _) e = liftT $ Left $ ParseError (extrPos e)
+ "Expression cannot be a higher order function. Yet..."
+ unify VoidType e = liftT $ Left $ ParseError (extrPos e)
+ "Expression cannot be a Void type."
+ unify (IdType _) e = liftT $ Left $ ParseError (extrPos e)
+ "Expression cannot be an polymorf type."
+ unify VarType e = typeExpr e
+ //we have to cheat to decorate the error, can be done nicer?
+ unify t e = StateT $ \s0 -> let res = runStateT m s0 in case res of
+ Left err = Left $ decErr e err
+ Right t = Right t //note, t :: (Type, Gamma)
+ where m = typeExpr e >>= \tex-> unify t tex
+
+instance unify Type where
+ unify IntType IntType = pure IntType
+ unify BoolType BoolType = pure BoolType
+ unify CharType CharType = pure CharType
+ unify t1 t2 = liftT $ Left $ UnifyError zero t1 t2
+
+instance zero Pos where
+ zero = {line=0,col=0}
+
+decErr :: Expr SemError -> SemError
+decErr e (UnifyError _ t1 t2) = UnifyError (extrPos e) t1 t2
+decErr e (ParseError _ s) = ParseError (extrPos e) s
+decErr e err = err
+dc2 :: Expr (Either SemError a) -> Either SemError a
+dc2 e (Right t) = Right t
+dc2 e (Left err) = Left err
-
+extrPos :: Expr -> Pos
+extrPos (VarExpr p _) = p
+extrPos (Op2Expr p _ _ _) = p
+extrPos (Op1Expr p _ _) = p
+extrPos (IntExpr p _) = p
+extrPos (CharExpr p _) = p
+extrPos (BoolExpr p _) = p
+extrPos (FunExpr p _) = p
+extrPos (EmptyListExpr p) = p
+extrPos (TupleExpr p _) = p
\ No newline at end of file
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