# pyjson5

A Python implementation of the JSON5 data format.

[JSON5](https://json5.org) extends the
[JSON](http://www.json.org) data interchange format to make it
slightly more usable as a configuration language:

* JavaScript-style comments (both single and multi-line) are legal.

* Object keys may be unquoted if they are legal ECMAScript identifiers

* Objects and arrays may end with trailing commas.

* Strings can be single-quoted, and multi-line string literals are allowed.

There are a few other more minor extensions to JSON; see the above page for
the full details.

This project implements a reader and writer implementation for Python;
where possible, it mirrors the
[standard Python JSON API](https://docs.python.org/library/json.html)
package for ease of use.

There is one notable difference from the JSON api: the `load()` and
`loads()` methods support optionally checking for (and rejecting) duplicate
object keys; pass `allow_duplicate_keys=False` to do so (duplicates are
allowed by default).

This is an early release. It has been reasonably well-tested, but it is
**SLOW**. It can be 1000-6000x slower than the C-optimized JSON module,
and is 200x slower (or more) than the pure Python JSON module.

## Known issues

* Did I mention that it is **SLOW**?

* The implementation follows Python3's `json` implementation where
  possible. This means that the `encoding` method to `dump()` is
  ignored, and unicode strings are always returned.

* The `cls` keyword argument that `json.load()`/`json.loads()` accepts
  to specify a custom subclass of ``JSONDecoder`` is not and will not be
  supported, because this implementation uses a completely different
  approach to parsing strings and doesn't have anything like the
  `JSONDecoder` class.

* The `cls` keyword argument that `json.dump()`/`json.dumps()` accepts
  is also not supported, for consistency with `json5.load()`. The `default`
  keyword *is* supported, though, and might be able to serve as a
  workaround.

## Running the tests
To run the tests, setup a venv and install the required dependencies with
`pip install -e '.[dev]'`, then run the tests with `python setup.py test`.


## Version History / Release Notes

* v0.9.6 (2021-06-21)
    * Bump development status classifier to 5 - Production/Stable, which
      the library feels like it is at this point. If I do end up significantly
      reworking things to speed it up and/or to add round-trip editing,
      that'll likely be a 2.0. If this version has no reported issues,
      I'll likely promote it to 1.0.
    * Also bump the tested Python versions to 2.7, 3.8 and 3.9, though
      earlier Python3 versions will likely continue to work as well.
    * [GitHub issue #46](https://github.dpranke/pyjson5/issues/36)
      Fix incorrect serialization of custom subtypes
    * Make it possible to run the tests if `hypothesis` isn't installed.

* v0.9.5 (2020-05-26)
    * Miscellaneous non-source cleanups in the repo, including setting
      up GitHub Actions for a CI system. No changes to the library from
      v0.9.4, other than updating the version.

* v0.9.4 (2020-03-26)
    * [GitHub pull #38](https://github.com/dpranke/pyjson5/pull/38)
      Fix from fredrik@fornwall.net for dumps() crashing when passed
      an empty string as a key in an object.

* v0.9.3 (2020-03-17)
    * [GitHub pull #35](https://github.com/dpranke/pyjson5/pull/35)
      Fix from pastelmind@ for dump() not passing the right args to dumps().
    * Fix from p.skouzos@novafutur.com to remove the tests directory from
      the setup call, making the package a bit smaller.

* v0.9.2 (2020-03-02)
    * [GitHub pull #34](https://github.com/dpranke/pyjson5/pull/34)
      Fix from roosephu@ for a badly formatted nested list.

* v0.9.1 (2020-02-09)
    * [GitHub issue #33](https://github.com/dpranke/pyjson5/issues/33):
       Fix stray trailing comma when dumping an object with an invalid key.

* v0.9.0 (2020-01-30)
    * [GitHub issue #29](https://github.com/dpranke/pyjson5/issues/29):
       Fix an issue where objects keys that started with a reserved
       word were incorrectly quoted.
    * [GitHub issue #30](https://github.com/dpranke/pyjson5/issues/30):
       Fix an issue where dumps() incorrectly thought a data structure
       was cyclic in some cases.
    * [GitHub issue #32](https://github.com/dpranke/pyjson5/issues/32):
       Allow for non-string keys in dicts passed to ``dump()``/``dumps()``.
       Add an ``allow_duplicate_keys=False`` to prevent possible
       ill-formed JSON that might result.

* v0.8.5 (2019-07-04)
    * [GitHub issue #25](https://github.com/dpranke/pyjson5/issues/25):
      Add LICENSE and README.md to the dist.
    * [GitHub issue #26](https://github.com/dpranke/pyjson5/issues/26):
      Fix printing of empty arrays and objects with indentation, fix
      misreporting of the position on parse failures in some cases.

* v0.8.4 (2019-06-11)
    * Updated the version history, too.

* v0.8.3 (2019-06-11)
    * Tweaked the README, bumped the version, forgot to update the version
      history :).

* v0.8.2 (2019-06-11)
    * Actually bump the version properly, to 0.8.2.

* v0.8.1 (2019-06-11)
    * Fix bug in setup.py that messed up the description. Unfortunately,
      I forgot to bump the version for this, so this also identifies as 0.8.0.

* v0.8.0 (2019-06-11)
    * Add `allow_duplicate_keys=True` as a default argument to
      `json5.load()`/`json5.loads()`. If you set the key to `False`, duplicate
      keys in a single dict will be rejected. The default is set to `True`
      for compatibility with `json.load()`, earlier versions of json5, and
      because it's simply not clear if people would want duplicate checking
      enabled by default.

* v0.7 (2019-03-31)
    * Changes dump()/dumps() to not quote object keys by default if they are
      legal identifiers. Passing `quote_keys=True` will turn that off
      and always quote object keys.
    * Changes dump()/dumps() to insert trailing commas after the last item
      in an array or an object if the object is printed across multiple lines
      (i.e., if `indent` is not None). Passing `trailing_commas=False` will
      turn that off.
    * The `json5.tool` command line tool now supports the `--indent`,
      `--[no-]quote-keys`, and `--[no-]trailing-commas` flags to allow
      for more control over the output, in addition to the existing
      `--as-json` flag.
    * The `json5.tool` command line tool no longer supports reading from
      multiple files, you can now only read from a single file or
      from standard input.
    * The implementation no longer relies on the standard `json` module
      for anything. The output should still match the json module (except
      as noted above) and discrepancies should be reported as bugs.

* v0.6.2 (2019-03-08)
    * Fix [GitHub issue #23](https://github.com/dpranke/pyjson5/issues/23) and
      pass through unrecognized escape sequences.

* v0.6.1 (2018-05-22)
    * Cleaned up a couple minor nits in the package.

* v0.6.0 (2017-11-28)
    * First implementation that attempted to implement 100% of the spec.

* v0.5.0 (2017-09-04)
    * First implementation that supported the full set of kwargs that
      the `json` module supports.
