ppbert

A simple command-line utility to pretty print structures encoded using Erlang's External Term Format. The input is read from stdin or a file and written to stdout, making ppbert a good candidate for shell pipelines.

At the moment, ppbert supports only a subset of the field types of the External Term Format:

Supported types:

• Small integers (tag: 97);
• Integers (tag: 98);
• Floating-point numbers (tags: 70, 99);
• Big integers (tags: 110, 111);
• Latin-1 atoms (tags: 100, 115);
• UTF-8 atoms (tags: 118, 119);
• Strings (tag: 107);
• Binaries (tag: 109);
• Tuples (tags: 104, 105);
• Lists (tags: 106, 108);
• Maps (tag: 116).

Usage

``` $ ppbert -h ppbert 0.2.2 Vincent Foley Pretty print structure encoded in Erlang's External Term Format

USAGE: ppbert [OPTIONS] []

FLAGS: -h, --help Prints help information -V, --version Prints version information

OPTIONS: -i, --indent-width -m, --max-terms-per-line

ARGS: ...

$ ppbert mini_dict.bert [ {host, "localhost"}, {port, 80}, { headers, [ { <<"X-Real-Ip">>, {127, 0, 0, 1} }, {<<"Keep-alive">>, true} ] } ]

$ printf "\x83\x77\x04atom" | ppbert atom ```

Performance

Ppbert is written in Rust and offers an appreciable performance gain over using Erlang's erlang:binary_to_term/1 and io:format/2.

```sh $ cat erl_ppbert

!/usr/bin/env escript

main(Args) -> lists:foreach(fun (Filename) -> {ok, Binary} = file:readfile(Filename), io:format("~p~n", [binaryto_term(Binary)]) end, Args).

$ du large.bert 96M large.bert

$ time ./erl_ppbert large.bert >/dev/null

real 1m10.968s user 0m49.644s sys 0m13.628s

$ time ppbert large.bert >/dev/null

real 0m6.902s user 0m6.116s sys 0m0.452s ```

Future work

• ~~Add flags to control the pretty printing (e.g., indentation width, number of basic values on a single line, etc.).~~
• Add a jq-like query language.
• ~~Write a man page.~~