ipv4address.citrus

grammar IPv4Address
  # A host identified by an IPv4 literal address is represented in
  # dotted-decimal notation (a sequence of four decimal numbers in the
  # range 0 to 255, separated by "."), as described in [RFC1123] by
  # reference to [RFC0952].  Note that other forms of dotted notation may
  # be interpreted on some platforms, as described in Section 7.4, but
  # only the dotted-decimal form of four octets is allowed by this
  # grammar.
  rule IPv4address
    (dec-octet '.' dec-octet '.' dec-octet '.' dec-octet) {
      def version; 4 end
    }
  end

  rule dec-octet
      '25' [0-5]        # 250-255
    | '2' [0-4] DIGIT   # 200-249
    | '1' DIGIT DIGIT   # 100-199
    | [1-9] DIGIT       # 10-99
    | DIGIT             # 0-9
  end

  rule DIGIT
    [0-9]
  end
end