This is an Elixir version of a parser for the Fallout 4 Pipboy protocol. It's also a chance to learn more about Elixir. My more complete implementation in Ruby can be found here, along with details on the protocol itself.

The Elixir version successfully parses messages from a binary stream, and will additionally parse messages of type 3 into full data updates.

Elixir's binary pattern matching turned out to be a stellar choice, and made parsing the binary stream far easier than Ruby. No surprise given Erlang's roots.

I also (for better or for worse) got to learn a little bit about macros.

PipParser takes input from STDIN. Below, we pipe a captured binary dump of some Pipboy traffic to PipParser.

$ mix run -e PipParser.run < test.bin
%PipUpdate{contents: "$General", id: 32140, type: :string}
%PipUpdate{contents: 72, id: 32156, type: :sint32}
%PipUpdate{contents: "Locations Discovered", id: 32155, type: :string}
%PipUpdate{contents: true, id: 32157, type: :bool}
%PipUpdate{contents: {[{32156, "value"}, {32155, "text"},
   {32157, "showIfZero"}], []}, id: 32154, type: :dict_update}
%PipUpdate{contents: 19, id: 32160, type: :sint32}
%PipUpdate{contents: "Locations Cleared", id: 32159, type: :string}
%PipUpdate{contents: true, id: 32161, type: :bool}
%PipUpdate{contents: {[{32160, "value"}, {32159, "text"},
   {32161, "showIfZero"}], []}, id: 32158, type: :dict_update}
%PipUpdate{contents: 24, id: 32164, type: :sint32}
%PipUpdate{contents: "Days Passed", id: 32163, type: :string}

A set of macros to provide short-hand syntax for various data types relevant to the Pipboy binary protocol (uint8, float32, etc).

A custom Stream that pulls from STDIN, then extracts and emits tuples representing individual messages.

Parsing functions for parsing Pipboy messages of type 3 a.k.a. data updates. Data updates are the most interesting form of data the Pipboy sends, and also the most complicated to parse.

Small examples of these parsing functions can be found in the tests (pip_update_test.exs).

Right now there's a single run function in PipParser that shows a pipeline streaming data from STDIN, selecting messages of type 3, parsing the data upates, and printing them.