5 releases

Uses old Rust 2015

0.8.2 Oct 17, 2018
0.8.1 Aug 18, 2016
0.8.0 Aug 11, 2016
0.1.1 Jul 17, 2016
0.1.0 Jul 17, 2016

#1628 in Parser implementations

34 downloads per month

MIT license

3.5K SLoC

hjson-rust for serde

Build Status crate

Hjson Intro

  # specify rate in requests/second (because comments are helpful!)
  rate: 1000

  // prefer c-style comments?
  /* feeling old fashioned? */

  # did you notice that rate doesn't need quotes?
  hey: look ma, no quotes for strings either!

  # best of all
  notice: []
  anything: ?

  # yes, commas are optional!

The Rust implementation of Hjson is based on the Serde JSON Serialization Library. For other platforms see hjson.github.io.

This crate is a Rust library for parsing and generating Human JSON Hjson. It is built upon Serde, a high performance generic serialization framework.


This crate works with Cargo and can be found on crates.io with a Cargo.toml like:

serde = "*"
serde-hjson = "*"

From the Commandline

Install with cargo install hjson

Hjson, the Human JSON.

  hjson [options]
  hjson [options] <input>
  hjson (-h | --help)
  hjson (-V | --version)

  -h --help     Show this screen.
  -j            Output as formatted JSON.
  -c            Output as JSON.
  -V --version  Show version.


  • run hjson test.json > test.hjson to convert to Hjson
  • run hjson -j test.hjson > test.json to convert to JSON


extern crate serde;
extern crate serde_hjson;

use serde_hjson::{Map,Value};

fn main() {

    // Now let's look at decoding Hjson data

    let sample_text=r#"
        # specify rate in requests/second
        rate: 1000

    // Decode and unwrap.
    let mut sample: Map<String, Value> = serde_hjson::from_str(&sample_text).unwrap();

    // scope to control lifetime of borrow
        // Extract the rate
        let rate = sample.get("rate").unwrap().as_f64().unwrap();
        println!("rate: {}", rate);

        // Extract the array
        let array : &mut Vec<Value> = sample.get_mut("array").unwrap().as_array_mut().unwrap();
        println!("first: {}", array.get(0).unwrap());

        // Add a value

    // Encode to Hjson
    let sample2 = serde_hjson::to_string(&sample).unwrap();
    println!("Hjson:\n{}", sample2);


see Rust doc


see history.md


~126K SLoC