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# A small experiment that demonstrates graphivz painting of parsers. The parser
# here has been taken from the example/ip_parser.rb
#
$:.unshift File.dirname(__FILE__) + "/../lib"
require 'parslet'
module IPv4
include Parslet
# 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(:ipv4) {
(dec_octet >> str('.') >> dec_octet >> str('.') >>
dec_octet >> str('.') >> dec_octet).as(:ipv4)
}
rule(:dec_octet) {
str('25') >> match("[0-5]") |
str('2') >> match("[0-4]") >> digit |
str('1') >> digit >> digit |
match('[1-9]') >> digit |
digit
}
rule(:digit) {
match('[0-9]')
}
end
# Must be used in concert with IPv4
module IPv6
include Parslet
rule(:colon) { str(':') }
rule(:dcolon) { colon >> colon }
# h16 :
def h16r(times)
(h16 >> colon).repeat(times, times)
end
# : h16
def h16l(times)
(colon >> h16).repeat(0,times)
end
# A 128-bit IPv6 address is divided into eight 16-bit pieces. Each piece is
# represented numerically in case-insensitive hexadecimal, using one to four
# hexadecimal digits (leading zeroes are permitted). The eight encoded
# pieces are given most-significant first, separated by colon characters.
# Optionally, the least-significant two pieces may instead be represented in
# IPv4 address textual format. A sequence of one or more consecutive
# zero-valued 16-bit pieces within the address may be elided, omitting all
# their digits and leaving exactly two consecutive colons in their place to
# mark the elision.
rule(:ipv6) {
(
(
h16r(6) |
dcolon >> h16r(5) |
h16.maybe >> dcolon >> h16r(4) |
(h16 >> h16l(1)).maybe >> dcolon >> h16r(3) |
(h16 >> h16l(2)).maybe >> dcolon >> h16r(2) |
(h16 >> h16l(3)).maybe >> dcolon >> h16r(1) |
(h16 >> h16l(4)).maybe >> dcolon
) >> ls32 |
(h16 >> h16l(5)).maybe >> dcolon >> h16 |
(h16 >> h16l(6)).maybe >> dcolon
).as(:ipv6)
}
rule(:h16) {
hexdigit.repeat(1,4)
}
rule(:ls32) {
(h16 >> colon >> h16) |
ipv4
}
rule(:hexdigit) {
digit | match("[a-fA-F]")
}
end
class IPP < Parslet::Parser
include IPv4
include IPv6
rule(:ipp) { ipv4 | ipv6 }
root :ipp
end
require 'parslet/graphviz'
IPP.graph(pdf: 'ip.pdf')
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