resMaybe :: Variant a => ArgRes (Maybe a)
resMaybe p = 
  catchComException
    (readVarError p >> return Nothing)
    (\ _ -> fmap Just (resVariant p))
resMaybe :: Variant a => ArgRes (Maybe a)
resMaybe p = 
  catchComException
    (readVarError p >> return Nothing)
    (\ _ -> fmap Just (resVariant p))
resMaybe p = 
  catchComException
    (readVarError p >> return Nothing)
    (\ _ -> fmap Just (resVariant p))