<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/stable/?badge=stable"><img alt="Documentation Status" src="http://readthedocs.org/projects/black/badge/?version=stable"></a>
+<a href="https://black.readthedocs.io/en/stable/?badge=stable"><img alt="Documentation Status" src="https://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/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/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)**
### Command line options
-Black doesn't provide many options. You can list them by running
+*Black* doesn't provide many options. You can list them by running
`black --help`:
```text
Options:
-l, --line-length INTEGER Where to wrap around. [default: 88]
+ --py36 Allow using Python 3.6-only syntax on all input
+ files. This will put trailing commas in function
+ signatures and calls also after *args and
+ **kwargs. [default: per-file auto-detection]
+ --pyi Format all input files like typing stubs
+ regardless of file extension (useful when piping
+ source on standard input).
+ -S, --skip-string-normalization
+ Don't normalize string quotes or prefixes.
--check Don't write the files back, just return the
status. Return code 0 means nothing would
change. Return code 1 means some files would be
for each file on stdout.
--fast / --safe If --fast given, skip temporary sanity checks.
[default: --safe]
+ --include TEXT A regular expression that matches files and
+ directories that should be included on
+ recursive searches. On Windows, use forward
+ slashes for directories. [default: \.pyi?$]
+ --exclude TEXT A regular expression that matches files and
+ directories that should be excluded on
+ recursive searches. On Windows, use forward
+ slashes for directories. [default:
+ build/|buck-out/|dist/|_build/|\.git/|\.hg/|
+ \.mypy_cache/|\.tox/|\.venv/]
-q, --quiet Don't emit non-error messages to stderr. Errors
are still emitted, silence those with
2>/dev/null.
+ -v, --verbose Also emit messages to stderr about files
+ that were not changed or were ignored due to
+ --exclude=.
--version Show the version and exit.
+ --config PATH Read configuration from PATH.
--help Show this message and exit.
```
imports cannot fit in the allotted length, it's always split into one
element per line. This minimizes diffs as well as enables readers of
code to find which commit introduced a particular entry. This also
-makes *Black* compatible with [isort](https://pypi.org/p/isort/). Use
-`multi_line_output=3`, `include_trailing_comma=True`,
-`force_grid_wrap=0`, and `line_length=88` in your isort config.
+makes *Black* compatible with [isort](https://pypi.org/p/isort/) with
+the following configuration.
+
+<details>
+<summary>A compatible `.isort.cfg`</summary>
+
+```
+[settings]
+multi_line_output=3
+include_trailing_comma=True
+force_grid_wrap=0
+combine_as_imports=True
+line_length=88
+```
+The equivalent command line is:
+```
+$ isort --multi-line=3 --trailing-comma --force-grid-wrap=0 --combine-as --line-width=88 [ file.py ]
+```
+</details>
### Line length
It will also insert proper spacing before and after function definitions.
It's one line before and after inner functions and two lines before and
-after module-level functions. *Black* will not put empty lines between
-function/class definitions and standalone comments that immediately precede
-the given function/class.
+after module-level functions and classes. *Black* will not put empty
+lines between function/class definitions and standalone comments that
+immediately precede the given function/class.
+
+*Black* will enforce single empty lines between a class-level docstring
+and the first following field or method. This conforms to
+[PEP 257](https://www.python.org/dev/peps/pep-0257/#multi-line-docstrings).
+
+*Black* won't insert empty lines after function docstrings unless that
+empty line is required due to an inner function starting immediately
+after.
### Trailing commas
key. My recommendation here is to keep using whatever is faster to type
and let *Black* handle the transformation.
+If you are adopting *Black* in a large project with pre-existing string
+conventions (like the popular ["single quotes for data, double quotes for
+human-readable strings"](https://stackoverflow.com/a/56190)), you can
+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
Some popular APIs, like ORMs, use call chaining. This API style is known
as a [fluent interface](https://en.wikipedia.org/wiki/Fluent_interface).
-*Black* formats those treating dots that follow a call or an indexing
+*Black* formats those by treating dots that follow a call or an indexing
operation like a very low priority delimiter. It's easier to show the
behavior than to explain it. Look at the example:
```py3
* 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`.
+ - 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.
Configuration:
* `g:black_fast` (defaults to `0`)
* `g:black_linelength` (defaults to `88`)
+* `g:black_skip_string_normalization` (defaults to `0`)
* `g:black_virtualenv` (defaults to `~/.vim/black`)
To install with [vim-plug](https://github.com/junegunn/vim-plug):
create a virtualenv manually and point `g:black_virtualenv` to it.
The plugin will use it.
+To run *Black* on save, add the following line to `.vimrc` or `init.vim`:
+
+```
+autocmd BufWritePre *.py execute ':Black'
+```
+
**How to get Vim with Python 3.6?**
On Ubuntu 17.10 Vim comes with Python 3.6 by default.
On macOS with Homebrew run: `brew install vim --with-python3`.
### Visual Studio Code
-Use [joslarson.black-vscode](https://marketplace.visualstudio.com/items?itemName=joslarson.black-vscode).
+Use the [Python extension](https://marketplace.visualstudio.com/items?itemName=ms-python.python)
+([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! ✨ 🍰 ✨
Any tool that can pipe code through *Black* using its stdio mode (just
-[use `-` as the file name](http://www.tldp.org/LDP/abs/html/special-chars.html#DASHREF2)).
+[use `-` as the file name](https://www.tldp.org/LDP/abs/html/special-chars.html#DASHREF2)).
The formatted code will be returned on stdout (unless `--check` was
passed). *Black* will still emit messages on stderr but that shouldn't
affect your use case.
rev: stable
hooks:
- id: black
- args: [--line-length=88, --safe]
- python_version: python3.6
+ 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 `python_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
*Black* remembers files it has already formatted, unless the `--diff` flag is used or
code is passed via standard input. This information is stored per-user. The exact
-location of the file depends on the black version and the system on which black
+location of the file depends on the *Black* version and the system on which *Black*
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
**Dusty Phillips**, [writer](https://smile.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=dusty+phillips):
-> Black is opinionated so you don't have to be.
+> *Black* is opinionated so you don't have to be.
**Hynek Schlawack**, [creator of `attrs`](http://www.attrs.org/), core
developer of Twisted and CPython:
[](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: [](https://github.com/ambv/black)
MIT
-## Contributing to Black
+## Contributing to *Black*
In terms of inspiration, *Black* is about as configurable as *gofmt*.
This is deliberate.
## Change Log
-### 18.5b1 (unreleased)
+### 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
+
+* hotfix: don't output human-facing information on stdout (#299)
+
+* hotfix: don't output cake emoji on non-zero return code (#300)
+
+
+### 18.6b0
+
+* added `--include` and `--exclude` (#270)
+
+* added `--skip-string-normalization` (#118)
+
+* added `--verbose` (#283)
+
+* the header output in `--diff` now actually conforms to the unified diff spec
+
+* fixed long trivial assignments being wrapped in unnecessary parentheses (#273)
+
+* fixed unnecessary parentheses when a line contained multiline strings (#232)
+
+* fixed stdin handling not working correctly if an old version of Click was
+ used (#276)
+
+* *Black* now preserves line endings when formatting a file in place (#258)
+
+
+### 18.5b1
+
+* added `--pyi` (#249)
+
+* added `--py36` (#249)
* Python grammar pickle caches are stored with the formatting caches, making
*Black* work in environments where site-packages is not user-writable (#192)
+* *Black* now enforces a PEP 257 empty line after a class-level docstring
+ (and/or fields) and the first method
+
* fixed invalid code produced when standalone comments were present in a trailer
that was omitted from line splitting on a large expression (#237)
* fixed unstable formatting when inline comments were moved around in
a trailer that was omitted from line splitting on a large expression
- (#238)
+ (#238)
+
+* fixed extra empty line between a class declaration and the first
+ method if no class docstring or fields are present (#219)
+
+* fixed extra empty line between a function signature and an inner
+ function or inner class (#196)
+
### 18.5b0
* generalized star expression handling, including double stars; this
fixes multiplication making expressions "unsafe" for trailing commas (#132)
-* Black no longer enforces putting empty lines behind control flow statements
+* *Black* no longer enforces putting empty lines behind control flow statements
(#90)
-* Black now splits imports like "Mode 3 + trailing comma" of isort (#127)
+* *Black* now splits imports like "Mode 3 + trailing comma" of isort (#127)
* fixed comment indentation when a standalone comment closes a block (#16, #32)
(#75)
* fixed handling of standalone comments within nested bracketed
- expressions; Black will no longer produce super long lines or put all
+ expressions; *Black* will no longer produce super long lines or put all
standalone comments at the end of the expression (#22)
* fixed 18.3a4 regression: don't crash and burn on empty lines with
trailing whitespace (#80)
* fixed 18.3a4 regression: `# yapf: disable` usage as trailing comment
- would cause Black to not emit the rest of the file (#95)
+ would cause *Black* to not emit the rest of the file (#95)
-* when CTRL+C is pressed while formatting many files, Black no longer
+* when CTRL+C is pressed while formatting many files, *Black* no longer
freaks out with a flurry of asyncio-related exceptions
* only allow up to two empty lines on module level and only single empty
### 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)**
projects / etc / vim.git / blobdiff