<p align="center">
<a href="https://travis-ci.org/ambv/black"><img alt="Build Status" src="https://travis-ci.org/ambv/black.svg?branch=master"></a>
-<a href="http://black.readthedocs.io/en/latest/?badge=latest"><img alt="Documentation Status" src="http://readthedocs.org/projects/black/badge/?version=latest"></a>
+<a href="http://black.readthedocs.io/en/stable/?badge=stable"><img alt="Documentation Status" src="http://readthedocs.org/projects/black/badge/?version=stable"></a>
<a href="https://coveralls.io/github/ambv/black?branch=master"><img alt="Coverage Status" src="https://coveralls.io/repos/github/ambv/black/badge.svg?branch=master"></a>
-<a href="https://github.com/ambv/black/blob/master/LICENSE"><img alt="License: MIT" src="http://black.readthedocs.io/en/latest/_static/license.svg"></a>
-<a href="https://pypi.python.org/pypi/black"><img alt="PyPI" src="http://black.readthedocs.io/en/latest/_static/pypi.svg"></a>
+<a href="https://github.com/ambv/black/blob/master/LICENSE"><img alt="License: MIT" src="http://black.readthedocs.io/en/stable/_static/license.svg"></a>
+<a href="https://pypi.python.org/pypi/black"><img alt="PyPI" src="http://black.readthedocs.io/en/stable/_static/pypi.svg"></a>
<a href="https://github.com/ambv/black"><img alt="Code style: black" src="https://img.shields.io/badge/code%20style-black-000000.svg"></a>
</p>
* it will read from standard input and write to standard output if `-`
is used as the filename;
* it only outputs messages to users on standard error;
-* exits with code 0 unless an internal error occured (or `--check` was
+* exits with code 0 unless an internal error occurred (or `--check` was
used).
*Black* ignores previous formatting and applies uniform horizontal
and vertical whitespace to your code. The rules for horizontal
-whitespace are pretty obvious and can be summarized as: do whatever
-makes `pycodestyle` happy. The coding style used by *Black* can be
-viewed as a strict subset of PEP 8.
+whitespace can be summarized as: do whatever makes `pycodestyle` happy.
+The coding style used by *Black* can be viewed as a strict subset of
+PEP 8.
As for vertical whitespace, *Black* tries to render one full expression
or simple statement per line. If this fits the allotted line length,
and `'''`). It will replace the latter with the former as long as it
does not result in more backslash escapes than before.
+*Black* also standardizes string prefixes, making them always lowercase.
+On top of that, if your code is already Python 3.6+ only or it's using
+the `unicode_literals` future import, *Black* will remove `u` from the
+string prefix as it is meaningless in those scenarios.
+
The main reason to standardize on a single form of quotes is aesthetics.
Having one kind of quotes everywhere reduces reader distraction.
It will also enable a future version of *Black* to merge consecutive
- `for (...) in (...):`
- `assert (...), (...)`
- `from X import (...)`
+- assignments like:
+ - `target = (...)`
+ - `target: type = (...)`
+ - `some, *un, packing = (...)`
+ - `augmented += (...)`
In those cases, parentheses are removed when the entire statement fits
in one line, or if the inner expression doesn't have any delimiters to
by calling `:BlackUpgrade` and restarting Vim.
If you need to do anything special to make your virtualenv work and
-install *Black* (for example you want to run a version from master), just
+install *Black* (for example you want to run a version from master),
create a virtualenv manually and point `g:black_virtualenv` to it.
The plugin will use it.
Use [sublack plugin](https://github.com/jgirardet/sublack).
+### IPython Notebook Magic
+
+Use [blackcellmagic](https://github.com/csurfer/blackcellmagic).
+
### Other editors
Atom/Nuclide integration is planned by the author, others will
## Change Log
+### 18.5a0 (unreleased)
+
+* slices are now formatted according to PEP 8 (#178)
+
+* parentheses are now also managed automatically on the right-hand side
+ of assignments and return statements (#140)
+
+* math operators now use their respective priorities for delimiting multiline
+ expressions (#148)
+
+* empty parentheses in a class definition are now removed (#145, #180)
+
+* string prefixes are now standardized to lowercase and `u` is removed
+ on Python 3.6+ only code and Python 2.7+ code with the `unicode_literals`
+ future import (#188, #198, #199)
+
+* fixed an invalid trailing comma sometimes left in imports (#185)
+
+* fixed non-deterministic formatting when multiple pairs of removable parentheses
+ were used (#183)
+
+* fixed not splitting long from-imports with only a single name
+
+* fixed Python 3.6+ file discovery by also looking at function calls with
+ unpacking. This fixed non-deterministic formatting if trailing commas
+ where used both in function signatures with stars and function calls
+ with stars but the former would be reformatted to a single line.
+
+
### 18.4a4
* don't populate the cache on `--check` (#175)
Multiple contributions by:
* [Anthony Sottile](mailto:asottile@umich.edu)
* [Artem Malyshev](mailto:proofit404@gmail.com)
+* [Christian Heimes](mailto:christian@python.org)
* [Daniel M. Capella](mailto:polycitizen@gmail.com)
* [Eli Treuherz](mailto:eli.treuherz@cgi.com)
* Hugo van Kemenade
* [Ivan Katanić](mailto:ivan.katanic@gmail.com)
+* [Jelle Zijlstra](mailto:jelle.zijlstra@gmail.com)
* [Jonas Obrist](mailto:ojiidotch@gmail.com)
* [Osaetin Daniel](mailto:osaetindaniel@gmail.com)
+* [Sunil Kapil](mailto:snlkapil@gmail.com)
* [Vishwas B Sharma](mailto:sharma.vishwas88@gmail.com)