ometa Flan {
  id = letter:t letterOrDigit+:ts -> (t+ts.join('')),
  nonletter = ('!' | '$' | '%' | '^' | '&' | '*' |
               '+' | '~' | '<' | '>' | '=' | '?' | '#' | ',' | '.' | '/'):s -> s,
  declaretoken = '@' (id | nonletter+):t -> t
}

Flan.matchAll('@hello', 'declaretoken')