operator :: Parser String
operator = do
  c <- Tok.opStart emptyDef
  cs <- many $ Tok.opLetter emptyDef
  return (c:cs)
operator :: Parser String
operator = do
  c <- Tok.opStart emptyDef
  cs <- many $ Tok.opLetter emptyDef
  return (c:cs)
operator = do
  c <- Tok.opStart emptyDef
  cs <- many $ Tok.opLetter emptyDef
  return (c:cs)