vassert_ = do
  val <- (TValExpr <$> expr_) <|> (pure TValNull)
  string ":"
  VAssert val <$> rel_ <*> many expr_
vassert_ = do
  val <- (TValExpr <$> expr_) <|> (pure TValNull)
  string ":"
  VAssert val <$> rel_ <*> many expr_
vassert_ = do
  val <- (TValExpr <$> expr_) <|> (pure TValNull)
  string ":"
  VAssert val <$> rel_ <*> many expr_