mlookup globalEnv _ (Just m) =
case elookup globalEnv m of
Just env' -> env'
- Nothing -> error ("undefined module name: " ++ show m)
+ Nothing -> error ("Interp: undefined module name: " ++ show m)
qlookup :: Menv -> Venv -> (Mname,Var) -> Value
qlookup globalEnv env (m,k) =