code: func yaml_parser_parse_flow_mapping_value(parser *yaml_parser_t, event *yaml_event_t, empty bool) bool {
  	token := peek_token(parser)
  	if token == nil {
  		return false
  	}
  	if empty {
  		parser.state = yaml_PARSE_FLOW_MAPPING_KEY_STATE
  		return yaml_parser_process_empty_scalar(parser, event, token.start_mark)
  	}
  	if token.typ == yaml_VALUE_TOKEN {
  		skip_token(parser)
  		token = peek_token(parser)
  		if token == nil {
  			return false
  		}
  		if token.typ != yaml_FLOW_ENTRY_TOKEN && token.typ != yaml_FLOW_MAPPING_END_TOKEN {
  			parser.states = append(parser.states, yaml_PARSE_FLOW_MAPPING_KEY_STATE)
  			return yaml_parser_parse_node(parser, event, false, false)
  		}
  	}
  	parser.state = yaml_PARSE_FLOW_MAPPING_KEY_STATE
  	return yaml_parser_process_empty_scalar(parser, event, token.start_mark)
  }
docs: // Parse the productions:
  // flow_mapping_entry   ::= flow_node | KEY flow_node? (VALUE flow_node?)?
  //                                   *                  ***** *
  //