recursive regexp pattern for JSON

json_matcher.rb

# coding: utf-8
# only works on 1.9+
# base idea is from:
#   - http://stackoverflow.com/questions/2583472/regex-to-validate-json
#   - http://www.slideshare.net/takesako/shibuyapm16-regexpjsonvalidator

module JsonMatcher

  NUMBER = /-? (?= [1-9]|0(?!\d) ) \d+ (\.\d+)? ([eE] [+-]? \d+)?/x
  BOOLEAN = /true | false | null/x
  STRING = /" ([^"\\\\]* | \\\\ ["\\\\bfnrt\/] | \\\\ u [0-9a-f]{4} )* "/x

  JS_NUMBER = /(?:-|\+)? (?=[1-9]|0(?!\d)) \d+ (\.\d+)? ([eE] [+-]? \d+)?/x
  JS_BOOLEAN = BOOLEAN
  JS_STRING_SINGLE_QUOTE = /' (?:\\'|\\\\|\r|\n|\s|[^\'])* '/x
  JS_STRING_DOUBLE_QUOTE = /
    " 
      (?:
        \\\\ |
        \\n |
        \\f |
        \\b |
        \\r |
        \\t |
        \\' |
        \\" |
        \\[0-8]{3} |
        \\x[0-9a-fA-F]{2} |
        \\u[0-9a-fA-F]{4} |
        \r |
        \n |
        \s |
        [^\"]
      )*
    "
  /x
  JS_STRING = /#{JS_STRING_SINGLE_QUOTE} | #{JS_STRING_DOUBLE_QUOTE}/x
  JS_BARE_STRING = /[0-9a-zA-Z_]+/

  
  # pattern of json
  JSON = /
    (?<json>
      (?<number>#{NUMBER}) |
      (?<boolean>#{BOOLEAN}) |
      (?<string>#{STRING}) |
      (?<array>
        \[ \s* \g<json> (?: \s* , \s* \g<json> )* \s* \]
      ) |
      (?<object>
        \{ \s* (?<pair> \g<string> \s* : \s* \g<json> ) (?: \s* , \s* \g<pair> )* \s* \}
      )
    )
  /x

  SPACE = /\r|\n|\s/x

  # pattern of JS expression which consists of combinatin of basic type value
  JS_EXP = /
    (?<jsexp>
      (?<number>#{JS_NUMBER}) |
      (?<boolean>#{JS_BOOLEAN}) |
      (?<string>#{JS_STRING}) |
      (?<array>
        \[ #{SPACE}* \g<jsexp> (?:#{SPACE}* , #{SPACE}* \g<jsexp>|#{SPACE}*,#{SPACE}*)* #{SPACE}* \]
      ) |
      (?<object>
        \{ 
          #{SPACE}* 
          (?<pair> 
            (?:#{JS_BARE_STRING}|#{JS_STRING})
            #{SPACE}* 
            : 
            #{SPACE}* 
            \g<jsexp>
          )
          (?: #{SPACE}* , #{SPACE}* \g<pair>)*
          #{SPACE}*
        \}
      )
    )
  /x

end

Thank you!