json.txt

# vim: set ts=4 sw=4 tw=0 et nocindent :

# 定义两个终结符
%token NUMBER
%token STRING

start: value                {get1}
     ;

value: object               {get1}
     | array                {get1}
     | STRING               {get_string}
     | NUMBER               {get_number}
     | 'true'               {get_true}
     | 'false'              {get_false}
     | 'null'               {get_null}
     ;

array: '[' array_items ']'                  {get_array}
     ;

array_items: array_items ',' value          {list_many}
           | value                          {list_one}
           |                                {list_empty}
           ;

object: '{' object_items '}'                {get_object}
      ;

object_items: object_items ',' item_pair    {list_many}
            | item_pair                     {list_one}
            |                               {list_empty}
            ;

item_pair: STRING ':' value                 {item_pair}
         ;

# 词法：忽略空白
@ignore [ \r\n\t]*

# 词法：忽略注释
@ignore //.*

# 词法：匹配 NUMBER 和 STRING
@match NUMBER [+-]?\d+(\.\d*)?
@match STRING "(?:\\.|[^"\\])*"