- unify t e = typeExpr e
- >>= \eithertype->case eithertype of
- Left e = pure $ Left e
- Right tex = unify t tex >>= \eitherun->case eitherun of
- Left err = pure $ Left $ decErr e err
- Right t = pure $ Right t
+ unify (IdType i) e = undef
+ //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
+
+replace :: String Type -> Env Void
+replace ident type = get >>= \(st, fr)->put ('Map'.fromList $
+ map (itupdate ident type) ('Map'.toList st), fr)
+ where
+ itupdate :: String Type (String, Type) -> (String, Type)
+ itupdate ident newtype ov=:(key, IdType type) = if (ident == type)
+ (key, newtype) ov
+ itupdate ident newtype (key, TupleType (t1, t2))
+ # (_, t1) = itupdate ident newtype (key, t1)
+ # (_, t2) = itupdate ident newtype (key, t2)
+ = (key, TupleType (t1, t2))
+ itupdate ident newtype (key, ListType t1)
+ # (_, t1) = itupdate ident newtype (key, t1)
+ = (key, ListType t1)
+ itupdate _ _ k = k