<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="https://black.readthedocs.io/en/stable/_static/license.svg"></a>
<a href="https://pypi.python.org/pypi/black"><img alt="PyPI" src="https://black.readthedocs.io/en/stable/_static/pypi.svg"></a>
+<a href="http://pepy.tech/project/black"><img alt="Downloads" src="http://pepy.tech/badge/black"></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>
*Black* makes code review faster by producing the smallest diffs
possible.
+Try it out now using the [Black Playground](https://black.now.sh).
+
---
*Contents:* **[Installation and usage](#installation-and-usage)** |
-**[The *Black* code style](#the-black-code-style)** |
+**[Code style](#the-black-code-style)** |
+**[pyproject.toml](#pyprojecttoml)** |
**[Editor integration](#editor-integration)** |
**[Version control integration](#version-control-integration)** |
**[Ignoring unmodified files](#ignoring-unmodified-files)** |
**[Testimonials](#testimonials)** |
**[Show your style](#show-your-style)** |
-**[License](#license)** |
**[Contributing](#contributing-to-black)** |
**[Change Log](#change-log)** |
**[Authors](#authors)**
that were not changed or were ignored due to
--exclude=.
--version Show the version and exit.
+ --config PATH Read configuration from PATH.
--help Show this message and exit.
```
pass `--skip-string-normalization` on the command line. This is meant as
an adoption helper, avoid using this for new projects.
+### Numeric literals
+
+*Black* standardizes most numeric literals to use lowercase letters: `0xab`
+instead of `0XAB` and `1e10` instead of `1E10`. Python 2 long literals are
+styled as `2L` instead of `2l` to avoid confusion between `l` and `1`. In
+Python 3.6+, *Black* adds underscores to long numeric literals to aid
+readability: `100000000` becomes `100_000_000`.
### Line breaks & binary operators
* use `float` instead of `Union[int, float]`.
+## pyproject.toml
+
+*Black* is able to read project-specific default values for its
+command line options from a `pyproject.toml` file. This is
+especially useful for specifying custom `--include` and `--exclude`
+patterns for your project.
+
+**Pro-tip**: If you're asking yourself "Do I need to configure anything?"
+the answer is "No". *Black* is all about sensible defaults.
+
+
+### What on Earth is a `pyproject.toml` file?
+
+[PEP 518](https://www.python.org/dev/peps/pep-0518/) defines
+`pyproject.toml` as a configuration file to store build system
+requirements for Python projects. With the help of tools
+like [Poetry](https://poetry.eustace.io/) or
+[Flit](https://flit.readthedocs.io/en/latest/) it can fully replace the
+need for `setup.py` and `setup.cfg` files.
+
+
+### Where *Black* looks for the file
+
+By default *Black* looks for `pyproject.toml` starting from the common
+base directory of all files and directories passed on the command line.
+If it's not there, it looks in parent directories. It stops looking
+when it finds the file, or a `.git` directory, or a `.hg` directory,
+or the root of the file system, whichever comes first.
+
+If you're formatting standard input, *Black* will look for configuration
+starting from the current working directory.
+
+You can also explicitly specify the path to a particular file that you
+want with `--config`. In this situation *Black* will not look for any
+other file.
+
+If you're running with `--verbose`, you will see a blue message if
+a file was found and used.
+
+
+### Configuration format
+
+As the file extension suggests, `pyproject.toml` is a [TOML](https://github.com/toml-lang/toml) file. It contains separate
+sections for different tools. *Black* is using the `[tool.black]`
+section. The option keys are the same as long names of options on
+the command line.
+
+Note that you have to use single-quoted strings in TOML for regular
+expressions. It's the equivalent of r-strings in Python. Multiline
+strings are treated as verbose regular expressions by Black. Use `[ ]`
+to denote a significant space character.
+
+<details>
+<summary>Example `pyproject.toml`</summary>
+
+```toml
+[tool.black]
+line-length = 88
+py36 = true
+include = '\.pyi?$'
+exclude = '''
+/(
+ \.git
+ | \.hg
+ | \.mypy_cache
+ | \.tox
+ | \.venv
+ | _build
+ | buck-out
+ | build
+ | dist
+
+ # The following are specific to Black, you probably don't want those.
+ | blib2to3
+ | tests/data
+)/
+'''
+```
+
+</details>
+
+### Lookup hierarchy
+
+Command-line options have defaults that you can see in `--help`.
+A `pyproject.toml` can override those defaults. Finally, options
+provided by the user on the command line override both.
+
+*Black* will only ever use one `pyproject.toml` file during an entire
+run. It doesn't look for multiple files, and doesn't compose
+configuration from different levels of the file hierarchy.
+
+
## Editor integration
### Emacs
- Name: Black
- Description: Black is the uncompromising Python code formatter.
- Program: <install_location_from_step_2>
- - Arguments: $FilePath$
+ - Arguments: `$FilePath$`
5. Format the currently opened file by selecting `Tools -> External Tools -> black`.
- Alternatively, you can set a keyboard shortcut by navigating to `Preferences -> Keymap -> External Tools -> External Tools - Black`.
+6. Optionally, run Black on every file save:
+
+ 1. Make sure you have the [File Watcher](https://plugins.jetbrains.com/plugin/7177-file-watchers) plugin installed.
+ 2. Go to `Preferences -> Tools -> File Watchers` and click `+` to add a new watcher:
+ - Name: Black
+ - File type: Python
+ - Scope: Project Files
+ - Program: <install_location_from_step_2>
+ - Arguments: `$FilePath$`
+ - Output paths to refresh: `$FilePathRelativeToProjectRoot$`
+ - Working directory: `$ProjectFileDir$`
### Vim
Commands and shortcuts:
-* `,=` or `:Black` to format the entire file (ranges not supported);
+* `:Black` to format the entire file (ranges not supported);
* `:BlackUpgrade` to upgrade *Black* inside the virtualenv;
* `:BlackVersion` to get the current version of *Black* inside the
virtualenv.
To run *Black* on save, add the following line to `.vimrc` or `init.vim`:
```
-autocmd BufWritePost *.py execute ':Black'
+autocmd BufWritePre *.py execute ':Black'
```
**How to get Vim with Python 3.6?**
### Visual Studio Code
Use the [Python extension](https://marketplace.visualstudio.com/items?itemName=ms-python.python)
-([instructions](https://code.visualstudio.com/docs/python/editing#_formatting))
-or [joslarson.black-vscode](https://marketplace.visualstudio.com/items?itemName=joslarson.black-vscode).
+([instructions](https://code.visualstudio.com/docs/python/editing#_formatting)).
### SublimeText 3
Use [blackcellmagic](https://github.com/csurfer/blackcellmagic).
+### Python Language Server
+
+If your editor supports the [Language Server Protocol](https://langserver.org/)
+(Atom, Sublime Text, Visual Studio Code and many more), you can use
+the [Python Language Server](https://github.com/palantir/python-language-server) with the
+[pyls-black](https://github.com/rupert/pyls-black) plugin.
+
+
+### Atom/Nuclide
+
+Use [atom-black](https://github.com/hauntsaninja/atom-black).
+
+
### Other editors
-Atom/Nuclide integration is planned by the author, others will
-require external contributions.
+Other editors will require external contributions.
Patches welcome! ✨ 🍰 ✨
rev: stable
hooks:
- id: black
- args: [--line-length=88, --safe]
language_version: python3.6
```
Then run `pre-commit install` and you're ready to go.
-`args` in the above config is optional but shows you how you can change
-the line length if you really need to. If you're already using Python
-3.7, switch the `language_version` accordingly. Finally, `stable` is a tag
-that is pinned to the latest release on PyPI. If you'd rather run on
-master, this is also an option.
+Avoid using `args` in the hook. Instead, store necessary configuration
+in `pyproject.toml` so that editors and command-line usage of Black all
+behave consistently for your project. See *Black*'s own `pyproject.toml`
+for an example.
+
+If you're already using Python 3.7, switch the `language_version`
+accordingly. Finally, `stable` is a tag that is pinned to the latest
+release on PyPI. If you'd rather run on master, this is also an option.
## Ignoring unmodified files
is run. The file is non-portable. The standard location on common operating systems
is:
-* Windows: `C:\\Users\<username>\AppData\Local\black\black\Cache\<version>\cache.<line-length>.pickle`
-* macOS: `/Users/<username>/Library/Caches/black/<version>/cache.<line-length>.pickle`
-* Linux: `/home/<username>/.cache/black/<version>/cache.<line-length>.pickle`
+* Windows: `C:\\Users\<username>\AppData\Local\black\black\Cache\<version>\cache.<line-length>.<file-mode>.pickle`
+* macOS: `/Users/<username>/Library/Caches/black/<version>/cache.<line-length>.<file-mode>.pickle`
+* Linux: `/home/<username>/.cache/black/<version>/cache.<line-length>.<file-mode>.pickle`
+
+`file-mode` is an int flag that determines whether the file was formatted as 3.6+ only,
+as .pyi, and whether string normalization was omitted.
## Testimonials
[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)
```
+Using the badge in README.rst:
+```
+.. image:: https://img.shields.io/badge/code%20style-black-000000.svg
+ :target: https://github.com/ambv/black
+```
+
Looks like this: [![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)
## Change Log
+### 18.8b0
+
+* adjacent string literals are now correctly split into multiple lines (#463)
+
+* numeric literals are now formatted by *Black* (#452, #461, #464, #469):
+
+ * numeric literals are normalized to include `_` separators on Python 3.6+ code
+
+ * code with `_` in numeric literals is recognized as Python 3.6+
+
+ * most letters in numeric literals are lowercased (e.g., in `1e10` or `0xab`)
+
+* cache is now populated when `--check` is successful for a file which speeds up
+ consecutive checks of properly formatted unmodified files (#448)
+
+* fixed parsing of `__future__` imports with renames (#389)
+
+* fixed scope of `# fmt: off` when directly preceding `yield` and other nodes (#385)
+
+* note: the Vim plugin stopped registering ``,=`` as a default chord as it turned out
+ to be a bad idea (#415)
+
+* fixed formatting of lambda expressions with default arguments (#468)
+
+
+### 18.6b4
+
+* hotfix: don't freeze when multiple comments directly precede `# fmt: off` (#371)
+
+
+### 18.6b3
+
+* typing stub files (`.pyi`) now have blank lines added after constants (#340)
+
+* `# fmt: off` and `# fmt: on` are now much more dependable:
+
+ * they now work also within bracket pairs (#329)
+
+ * they now correctly work across function/class boundaries (#335)
+
+ * they now work when an indentation block starts with empty lines or misaligned
+ comments (#334)
+
+* made Click not fail on invalid environments; note that Click is right but the
+ likelihood we'll need to access non-ASCII file paths when dealing with Python source
+ code is low (#277)
+
+* fixed improper formatting of f-strings with quotes inside interpolated
+ expressions (#322)
+
+* fixed unnecessary slowdown when long list literals where found in a file
+
+* fixed unnecessary slowdown on AST nodes with very many siblings
+
+* fixed cannibalizing backslashes during string normalization
+
+* fixed a crash due to symbolic links pointing outside of the project directory (#338)
+
+
### 18.6b2
+* added `--config` (#65)
+
+* added `-h` equivalent to `--help` (#316)
+
* fixed improper unmodified file caching when `-S` was used
+* fixed extra space in string unpacking (#305)
+
+* fixed formatting of empty triple quoted strings (#313)
+
+* fixed unnecessary slowdown in comment placement calculation on lines without
+ comments
+
### 18.6b1
### 18.3a2
* changed positioning of binary operators to occur at beginning of lines
- instead of at the end, following [a recent change to PEP8](https://github.com/python/peps/commit/c59c4376ad233a62ca4b3a6060c81368bd21e85b)
+ instead of at the end, following [a recent change to PEP 8](https://github.com/python/peps/commit/c59c4376ad233a62ca4b3a6060c81368bd21e85b)
(#21)
* ignore empty bracket pairs while splitting. This avoids very weirdly
Maintained with [Carol Willing](mailto:carolcode@willingconsulting.com),
[Carl Meyer](mailto:carl@oddbird.net),
+[Jelle Zijlstra](mailto:jelle.zijlstra@gmail.com),
[Mika Naylor](mailto:mail@autophagy.io), and
[Zsolt Dollenstein](mailto:zsol.zsol@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)
* [Luka Sterbic](mailto:luka.sterbic@gmail.com)
* [Miguel Gaiowski](mailto:miggaiowski@gmail.com)
+* [Miroslav Shubernetskiy](mailto:miroslav@miki725.com)
+* [Neraste](neraste.herr10@gmail.com)
* [Osaetin Daniel](mailto:osaetindaniel@gmail.com)
* [Peter Bengtsson](mailto:mail@peterbe.com)
* [Stavros Korokithakis](mailto:hi@stavros.io)
* [Sunil Kapil](mailto:snlkapil@gmail.com)
* [Vishwas B Sharma](mailto:sharma.vishwas88@gmail.com)
-
----
-
-*Contents:*
-**[Installation and Usage](#installation-and-usage)** |
-**[The *Black* code style](#the-black-code-style)** |
-**[Editor integration](#editor-integration)** |
-**[Version control integration](#version-control-integration)** |
-**[Ignoring unmodified files](#ignoring-unmodified-files)** |
-**[Testimonials](#testimonials)** |
-**[Show your style](#show-your-style)** |
-**[License](#license)** |
-**[Contributing](#contributing-to-black)** |
-**[Change Log](#change-log)** |
-**[Authors](#authors)**