Abnf2

An ABNF parser generator

This version is a maintenance version from the now non-active ABNF developed by @vanstee

This version also relaxes the rules regarding ABNF file formats. The RFC requires that lines be separated by \r\n. This version also allows \n as an alternative in line with unix norms.

For an example of its usage in the wild, see the package ex_cldr; in particular the modules Cldr.Locale and Cldr.LanguageTag.Parser.

Example

iex(1)> parser = Abnf.load("priv/rfc5234.abnf")
Rfc5234
iex(2)> parser.parse(:rule, "DQUOTE = %x22\r\n")
[{:rule, "DQUOTE = %x22\r\n",
  [{:rulename, "DQUOTE",
    [{:ALPHA, "D", [{:literal, "D", []}]}, {:ALPHA, "Q", [{:literal, "Q", []}]},
     {:ALPHA, "U", [{:literal, "U", []}]}, {:ALPHA, "O", [{:literal, "O", []}]},
     {:ALPHA, "T", [{:literal, "T", []}]},
     {:ALPHA, "E", [{:literal, "E", []}]}]},
   {:"defined-as", " = ",
    [{:"c-wsp", " ", [{:WSP, " ", [{:SP, " ", [{:literal, " ", []}]}]}]},
     {:literal, "=", []},
     {:"c-wsp", " ", [{:WSP, " ", [{:SP, " ", [{:literal, " ", []}]}]}]}]},
   {:elements, "%x22",
    [{:alternation, "%x22",
      [{:concatenation, "%x22",
        [{:repetition, "%x22",
          [{:element, "%x22",
            [{:"num-val", "%x22",
              [{:literal, "%", []},
               {:"hex-val", "x22",
                [{:literal, "x", []},
                 {:HEXDIG, "2", [{:DIGIT, "2", [{:literal, "2", []}]}]},
                 {:HEXDIG, "2",
                  [{:DIGIT, "2", [{:literal, "2", []}]}]}]}]}]}]}]}]}]},
   {:"c-nl", "\r\n",
    [{:CRLF, "\r\n",
      [{:CR, "\r", [{:literal, "\r", []}]},
       {:LF, "\n", [{:literal, "\n", []}]}]}]}]}]

TODO

• [ ] Improve test coverage
• [ ] Log error messages during parsing
• [ ] Improve UX of parsing for specific rules
• [ ] Improve documentation

Installation

The package can be installed by:

1. Adding abnf2 to your list of dependencies in mix.exs:

   def deps do

    [{:abnf2, "~> 0.1.0"}]

   end