code: def mark(self):
          '''Mark the line and column information of the result of this parser.'''
          def pos(text, index):
              return ParseError.loc_info(text, index)
  
          @Parser
          def mark_parser(text, index):
              res = self(text, index)
              if res.status:
                  return Value.success(res.index, (pos(text, index), res.value, pos(text, res.index)))
              else:
                  return res  # failed.
          return mark_parsef mark(self):
          '''Mark the line and column information of the result of this parser.'''
          def pos(text, index):
              return ParseError.loc_info(text, index)
  
          @Parser
          def mark_parser(text, index):
              res = self(text, index)
              if res.status:
                  return Value.success(res.index, (pos(text, index), res.value, pos(text, res.index)))
              else:
                  return res  # failed.
          return mark_parser
docs: Mark the line and column information of the result of this parser.