Added some expression typechecking

[cc1516.git] / sem.icl

diff --git a/sem.icl b/sem.icl
index fc8614b..6e177ec 100644 (file)
--- a/sem.icl
+++ b/sem.icl
@@ -9,10 +9,12 @@ import Control.Applicative
 import Control.Monad
 import Control.Monad.State
 import Control.Monad.Identity
+import Math.Random
 import Control.Monad.Trans
 import StdMisc
-from StdFunc import id, const
+from StdFunc import id, const, o
 import StdString
+import StdTuple
 import StdList
 
 from Text import class Text(concat), instance Text String
@@ -20,7 +22,7 @@ from Text import class Text(concat), instance Text String
 import AST
 from parse import :: ParserOutput, :: Error
 
-:: Gamma :== 'Map'.Map String Type
+:: Gamma :== ('Map'.Map String Type, [String])
 :: Env a :== StateT Gamma (Either SemError) a
 
 //we need to redefine this even though it is in Control.Monad.State
@@ -29,23 +31,33 @@ instance MonadTrans (StateT Gamma) where
 
 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]
+getRandomStream :: Int -> [String]
+getRandomStream i = genIdents $ filter (isAlpha o toChar) (genRandInt i)
+       where
+               genIdents r = let (ic, r) = splitAt 5 r in [toString ic: genIdents r]
+
+freshIdent :: Gamma -> (String, Gamma)
+freshIdent (st, [ident:rest]) = case 'Map'.get ident st of
+       Nothing = (ident, (st, rest))
+       _ = freshIdent (st, rest)
 
 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)
+putIdent i t = gets (\(st, r)->'Map'.get i st) >>= \mt -> case mt of
+    Nothing = modify (\(st, r)->('Map'.put i t st, r))
+    Just t2 = unify t t2 >>= \t3-> modify (\(st, r)->('Map'.put i t3 st, r))
+
+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]
 
 sem :: AST -> SemOutput
-sem (AST vd fd) = case evalStateT m 'Map'.newMap of
+sem (AST vd fd) = case evalStateT m ('Map'.newMap, getRandomStream 0) of
     Left e = Left [e]
     Right (vds, fds) = Right (AST vds fds)
 where 
@@ -54,6 +66,8 @@ where
         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]
@@ -81,22 +95,25 @@ 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
+typeExpr (Op2Expr p e1 BiEquals e2) = typeExpr e1 >>= \t1 -> unify t1 e2 
+    >>| pure BoolType //todo, actually check t1 in Char,Bool,Int
+typeExpr (Op2Expr p e1 BiUnEqual e2) = typeExpr (Op2Expr p e1 BiEquals e2)
 //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
+typeExpr (Op2Expr p e1 BiLesser e2) = typeExpr e1 >>= \t1 -> unify t1 e2 
+    >>| pure BoolType //todo, actually check t1 in Char, Int
+typeExpr (Op2Expr p e1 BiGreater e2) = typeExpr (Op2Expr p e1 BiLesser e2)
+typeExpr (Op2Expr p e1 BiLesserEq e2) = typeExpr (Op2Expr p e1 BiLesser e2)
+typeExpr (Op2Expr p e1 BiGreaterEq e2) = typeExpr (Op2Expr p e1 BiLesser e2)
 //bool
-typeExpr (Op2Expr p e1 BiAnd e2) = undef
-typeExpr (Op2Expr p e1 BiOr e2) = undef
+typeExpr (Op2Expr p e1 BiAnd e2) = unify BoolType e1 >>| unify BoolType e2
+typeExpr (Op2Expr p e1 BiOr e2) = unify BoolType e1 >>| unify BoolType e2
 //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
+typeExpr (Op2Expr p e1 BiCons e2) = typeExpr e1 >>= \t1-> typeExpr e2 
+    >>= \t2-> unify (ListType t1) t2
+//typeExpr (FunExpr p FunCall) = undef
+typeExpr (EmptyListExpr p) = pure $ ListType IntType //we'll need quantified types
+//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
 
@@ -118,6 +135,7 @@ instance unify Type where
        unify IntType IntType = pure IntType
        unify BoolType BoolType = pure BoolType
        unify CharType CharType = pure CharType
+    unify (ListType t1) (ListType t2) = unify t1 t2
        unify t1 t2 = liftT $ Left $ UnifyError zero t1 t2
 
 instance zero Pos where