X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/1f445a01c8c073058ccd6ca6ceba8f527e6cbf15..dd6c674e3a33ac6d20faea751764aeafecdf34c2:/README.md?ds=inline diff --git a/README.md b/README.md index 69df9bc..0f1953d 100644 --- a/README.md +++ b/README.md @@ -1,291 +1,160 @@ -![Black Logo](https://raw.githubusercontent.com/ambv/black/master/docs/_static/logo2-readme.png) +![Black Logo](https://raw.githubusercontent.com/psf/black/main/docs/_static/logo2-readme.png) +

The Uncompromising Code Formatter

-Build Status -Documentation Status -Coverage Status -License: MIT -PyPI -Code style: black +Actions Status +Actions Status +Documentation Status +Coverage Status +License: MIT +PyPI +Downloads +conda-forge +Code style: black

> “Any color you like.” +_Black_ is the uncompromising Python code formatter. By using it, you agree to cede +control over minutiae of hand-formatting. In return, _Black_ gives you speed, +determinism, and freedom from `pycodestyle` nagging about formatting. You will save time +and mental energy for more important matters. + +Blackened code looks the same regardless of the project you're reading. Formatting +becomes transparent after a while and you can focus on the content instead. + +_Black_ makes code review faster by producing the smallest diffs possible. -*Black* is the uncompromising Python code formatter. By using it, you -agree to cease control over minutiae of hand-formatting. In return, -*Black* gives you speed, determinism, and freedom from `pycodestyle` -nagging about formatting. You will save time and mental energy for -more important matters. +Try it out now using the [Black Playground](https://black.vercel.app). Watch the +[PyCon 2019 talk](https://youtu.be/esZLCuWs_2Y) to learn more. -Blackened code looks the same regardless of the project you're reading. -Formatting becomes transparent after a while and you can focus on the -content instead. +--- -*Black* makes code review faster by producing the smallest diffs -possible. +**[Read the documentation on ReadTheDocs!](https://black.readthedocs.io/en/stable)** +--- -## Installation and Usage +## Installation and usage ### Installation -*Black* can be installed by running `pip install black`. It requires -Python 3.6.0+ to run but you can reformat Python 2 code with it, too. +_Black_ can be installed by running `pip install black`. It requires Python 3.6.2+ to +run. If you want to format Python 2 code as well, install with +`pip install black[python2]`. +If you can't wait for the latest _hotness_ and want to install from GitHub, use: + +`pip install git+git://github.com/psf/black` ### Usage To get started right away with sensible defaults: -``` +```sh black {source_file_or_directory} ``` -### Command line options - -Black doesn't provide many options. You can list them by running -`black --help`: - -```text -black [OPTIONS] [SRC]... - -Options: - -l, --line-length INTEGER Where to wrap around. [default: 88] - --check Don't write back the files, just return the - status. Return code 0 means nothing would - change. Return code 1 means some files would be - reformatted. Return code 123 means there was an - internal error. - --fast / --safe If --fast given, skip temporary sanity checks. - [default: --safe] - --version Show the version and exit. - --help Show this message and exit. -``` - -*Black* is a well-behaved Unix-style command-line tool: -* it does nothing if no sources are passed to it; -* 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 - used). - - -### NOTE: This is an early pre-release - -*Black* can already successfully format itself and the standard library. -It also sports a decent test suite. However, it is still very new. -Things will probably be wonky for a while. This is made explicit by the -"Alpha" trove classifier, as well as by the "a" in the version number. -What this means for you is that **until the formatter becomes stable, -you should expect some formatting to change in the future**. - -Also, as a temporary safety measure, *Black* will check that the -reformatted code still produces a valid AST that is equivalent to the -original. This slows it down. If you're feeling confident, use -``--fast``. - - -## The *Black* code style - -*Black* reformats entire files in place. It is not configurable. It -doesn't take previous formatting into account. It doesn't reformat -blocks that start with `# fmt: off` and end with `# fmt: on`. It also -recognizes [YAPF](https://github.com/google/yapf)'s block comments to -the same effect, as a courtesy for straddling code. - - -### How *Black* wraps lines - -*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. - -As for vertical whitespace, *Black* tries to render one full expression -or simple statement per line. If this fits the allotted line length, -great. -```py3 -# in: +You can run _Black_ as a package if running it as a script doesn't work: -l = [1, - 2, - 3, -] - -# out: - -l = [1, 2, 3] +```sh +python -m black {source_file_or_directory} ``` -If not, *Black* will look at the contents of the first outer matching -brackets and put that in a separate indented line. -```py3 -# in: +Further information can be found in our docs: -l = [[n for n in list_bosses()], [n for n in list_employees()]] +- [Usage and Configuration](https://black.readthedocs.io/en/stable/usage_and_configuration/index.html) -# out: +### NOTE: This is a beta product -l = [ - [n for n in list_bosses()], [n for n in list_employees()] -] -``` +_Black_ is already [successfully used](https://github.com/psf/black#used-by) by many +projects, small and big. Black has a comprehensive test suite, with efficient parallel +tests, and our own auto formatting and parallel Continuous Integration runner. However, +_Black_ is still beta. Things will probably be wonky for a while. This is made explicit +by the "Beta" trove classifier, as well as by the "b" in the version number. What this +means for you is that **until the formatter becomes stable, you should expect some +formatting to change in the future**. That being said, no drastic stylistic changes are +planned, mostly responses to bug reports. -If that still doesn't fit the bill, it will decompose the internal -expression further using the same rule, indenting matching brackets -every time. If the contents of the matching brackets pair are -comma-separated (like an argument list, or a dict literal, and so on) -then *Black* will first try to keep them on the same line with the -matching brackets. If that doesn't work, it will put all of them in -separate lines. -```py3 -# in: - -def very_important_function(template: str, *variables, file: os.PathLike, debug: bool = False): - """Applies `variables` to the `template` and writes to `file`.""" - with open(file, 'w') as f: - ... - -# out: - -def very_important_function( - template: str, - *variables, - file: os.PathLike, - debug: bool = False, -): - """Applies `variables` to the `template` and writes to `file`.""" - with open(file, 'w') as f: - ... -``` +Also, as a safety measure which slows down processing, _Black_ will check that the +reformatted code still produces a valid AST that is effectively equivalent to the +original (see the +[Pragmatism](https://black.readthedocs.io/en/stable/the_black_code_style/current_style.html#ast-before-and-after-formatting) +section for details). If you're feeling confident, use `--fast`. -You might have noticed that closing brackets are always dedented and -that a trailing comma is always added. Such formatting produces smaller -diffs; when you add or remove an element, it's always just one line. -Also, having the closing bracket dedented provides a clear delimiter -between two distinct sections of the code that otherwise share the same -indentation level (like the arguments list and the docstring in the -example above). - - -### Line length - -You probably noticed the peculiar default line length. *Black* defaults -to 88 characters per line, which happens to be 10% over 80. This number -was found to produce significantly shorter files than sticking with 80 -(the most popular), or even 79 (used by the standard library). In -general, [90-ish seems like the wise choice](https://youtu.be/wf-BqAjZb8M?t=260). - -If you're paid by the line of code you write, you can pass -`--line-length` with a lower number. *Black* will try to respect that. -However, sometimes it won't be able to without breaking other rules. In -those rare cases, auto-formatted code will exceed your allotted limit. - -You can also increase it, but remember that people with sight disabilities -find it harder to work with line lengths exceeding 100 characters. -It also adversely affects side-by-side diff review on typical screen -resolutions. Long lines also make it harder to present code neatly -in documentation or talk slides. - -If you're using Flake8, you can bump `max-line-length` to 88 and forget -about it. Alternatively, use [Bugbear](https://github.com/PyCQA/flake8-bugbear)'s -B950 warning instead of E501 and keep the max line length at 80 which -you are probably already using. You'd do it like this: -```ini -[flake8] -max-line-length = 80 -... -select = C,E,F,W,B,B950 -ignore = E501 -``` +## The _Black_ code style -You'll find *Black*'s own .flake8 config file is configured like this. -If you're curious about the reasoning behind B950, Bugbear's documentation -explains it. The tl;dr is "it's like highway speed limits, we won't -bother you if you overdo it by a few km/h". +_Black_ is a PEP 8 compliant opinionated formatter. _Black_ reformats entire files in +place. Style configuration options are deliberately limited and rarely added. It doesn't +take previous formatting into account (see [Pragmatism](#pragmatism) for exceptions). +Our documentation covers the current _Black_ code style, but planned changes to it are +also documented. They're both worth taking a look: -### Empty lines +- [The _Black_ Code Style: Current style](https://black.readthedocs.io/en/stable/the_black_code_style/current_style.html) +- [The _Black_ Code Style: Future style](https://black.readthedocs.io/en/stable/the_black_code_style/future_style.html) -*Black* avoids spurious vertical whitespace. This is in the spirit of -PEP 8 which says that in-function vertical whitespace should only be -used sparingly. One exception is control flow statements: *Black* will -always emit an extra empty line after ``return``, ``raise``, ``break``, -``continue``, and ``yield``. This is to make changes in control flow -more prominent to readers of your code. +Please refer to this document before submitting an issue. What seems like a bug might be +intended behaviour. -*Black* will allow single empty lines left by the original editors, -except when they're added within parenthesized expressions. Since such -expressions are always reformatted to fit minimal space, this whitespace -is lost. +### Pragmatism -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 put those empty lines also -between the function definition and any standalone comments that -immediately precede the given function. If you want to comment on the -entire function, use a docstring or put a leading comment in the function -body. +Early versions of _Black_ used to be absolutist in some respects. They took after its +initial author. This was fine at the time as it made the implementation simpler and +there were not many users anyway. Not many edge cases were reported. As a mature tool, +_Black_ does make some exceptions to rules it otherwise holds. +- [The _Black_ code style: Pragmatism](https://black.readthedocs.io/en/stable/the_black_code_style/current_style.html#pragmatism) -### Trailing commas +Please refer to this document before submitting an issue just like with the document +above. What seems like a bug might be intended behaviour. -*Black* will add trailing commas to expressions that are split -by comma where each element is on its own line. This includes function -signatures. +## Configuration -Unnecessary trailing commas are removed if an expression fits in one -line. This makes it 1% more likely that your line won't exceed the -allotted line length limit. Moreover, in this scenario, if you added -another argument to your call, you'd probably fit it in the same line -anyway. That doesn't make diffs any larger. +_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`/`--force-exclude`/`--extend-exclude` patterns for your +project. -One exception to removing trailing commas is tuple expressions with -just one element. In this case *Black* won't touch the single trailing -comma as this would unexpectedly change the underlying data type. Note -that this is also the case when commas are used while indexing. This is -a tuple in disguise: ```numpy_array[3, ]```. +You can find more details in our documentation: -One exception to adding trailing commas is function signatures -containing `*`, `*args`, or `**kwargs`. In this case a trailing comma -is only safe to use on Python 3.6. *Black* will detect if your file is -already 3.6+ only and use trailing commas in this situation. If you -wonder how it knows, it looks for f-strings and existing use of trailing -commas in function signatures that have stars in them. In other words, -if you'd like a trailing comma in this situation and *Black* didn't -recognize it was safe to do so, put it there manually and *Black* will -keep it. +- [The basics: Configuration via a file](https://black.readthedocs.io/en/stable/usage_and_configuration/the_basics.html#configuration-via-a-file) +And if you're looking for more general configuration documentation: -## Editor integration +- [Usage and Configuration](https://black.readthedocs.io/en/stable/usage_and_configuration/index.html) -* Visual Studio Code: [joslarson.black-vscode](https://marketplace.visualstudio.com/items?itemName=joslarson.black-vscode) -* Emacs: [proofit404/blacken](https://github.com/proofit404/blacken) +**Pro-tip**: If you're asking yourself "Do I need to configure anything?" the answer is +"No". _Black_ is all about sensible defaults. Applying those defaults will have your +code in compliance with many other _Black_ formatted projects. -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)). -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. +## Used by -Vim and Atom/Nuclide integration is planned by the author, others will -require external contributions. +The following notable open-source projects trust _Black_ with enforcing a consistent +code style: pytest, tox, Pyramid, Django Channels, Hypothesis, attrs, SQLAlchemy, +Poetry, PyPA applications (Warehouse, Bandersnatch, Pipenv, virtualenv), pandas, Pillow, +every Datadog Agent Integration, Home Assistant, Zulip. -Patches welcome! ✨ 🍰 ✨ +The following organizations use _Black_: Facebook, Dropbox, Mozilla, Quora, Duolingo. +Are we missing anyone? Let us know. ## Testimonials -**Dusty Phillips**, [writer](https://smile.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=dusty+phillips): +**Mike Bayer**, [author of `SQLAlchemy`](https://www.sqlalchemy.org/): -> Black is opinionated so you don't have to be. +> I can't think of any single tool in my entire programming career that has given me a +> bigger productivity increase by its introduction. I can now do refactorings in about +> 1% of the keystrokes that it would have taken me previously when we had no way for +> code to format itself. -**Hynek Schlawack**, [creator of `attrs`](http://www.attrs.org/), core -developer of Twisted and CPython: +**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. + +**Hynek Schlawack**, [creator of `attrs`](https://www.attrs.org/), core developer of +Twisted and CPython: > An auto-formatter that doesn't suck is all I want for Xmas! @@ -293,156 +162,66 @@ developer of Twisted and CPython: > At least the name is good. -**Kenneth Reitz**, creator of [`requests`](http://python-requests.org/) -and [`pipenv`](https://docs.pipenv.org/): +**Kenneth Reitz**, creator of [`requests`](http://python-requests.org/) and +[`pipenv`](https://readthedocs.org/projects/pipenv/): > This vastly improves the formatting of our code. Thanks a ton! - ## Show your style Use the badge in your project's README.md: -```markdown -[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black) +```md +[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black) ``` -Looks like this: [![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/psf/black +``` + +Looks like this: +[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black) ## License MIT +## Contributing -## Contributing to Black - -In terms of inspiration, *Black* is about as configurable as *gofmt* and -*rustfmt* are. This is deliberate. - -Bug reports and fixes are always welcome! However, before you suggest a -new feature or configuration knob, ask yourself why you want it. If it -enables better integration with some workflow, fixes an inconsistency, -speeds things up, and so on - go for it! On the other hand, if your -answer is "because I don't like a particular formatting" then you're not -ready to embrace *Black* yet. Such changes are unlikely to get accepted. -You can still try but prepare to be disappointed. - -More details can be found in [CONTRIBUTING](CONTRIBUTING.md). - - -## Change Log - -### 18.3a5 (unreleased) +Welcome! Happy to see you willing to make the project better. You can get started by +reading this: -* fixed 18.3a4 regression: don't crash and burn on empty lines with - trailing whitespace (#80) +- [Contributing: The basics](https://black.readthedocs.io/en/latest/contributing/the_basics.html) +You can also take a look at the rest of the contributing docs or talk with the +developers: -### 18.3a4 +- [Contributing documentation](https://black.readthedocs.io/en/latest/contributing/index.html) +- [Chat on Discord](https://discord.gg/RtVdv86PrH) -* `# fmt: off` and `# fmt: on` are implemented (#5) +## Change log -* automatic detection of deprecated Python 2 forms of print statements - and exec statements in the formatted file (#49) +The log has become rather long. It moved to its own file. -* use proper spaces for complex expressions in default values of typed - function arguments (#60) +See [CHANGES](https://black.readthedocs.io/en/latest/change_log.html). -* only return exit code 1 when --check is used (#50) - -* don't remove single trailing commas from square bracket indexing - (#59) - -* don't omit whitespace if the previous factor leaf wasn't a math - operator (#55) - -* omit extra space in kwarg unpacking if it's the first argument (#46) - -* omit extra space in [Sphinx auto-attribute comments](http://www.sphinx-doc.org/en/stable/ext/autodoc.html#directive-autoattribute) - (#68) - - -### 18.3a3 - -* don't remove single empty lines outside of bracketed expressions - (#19) - -* added ability to pipe formatting from stdin to stdin (#25) - -* restored ability to format code with legacy usage of `async` as - a name (#20, #42) - -* even better handling of numpy-style array indexing (#33, again) - - -### 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) - (#21) - -* ignore empty bracket pairs while splitting. This avoids very weirdly - looking formattings (#34, #35) - -* remove a trailing comma if there is a single argument to a call - -* if top level functions were separated by a comment, don't put four - empty lines after the upper function - -* fixed unstable formatting of newlines with imports - -* fixed unintentional folding of post scriptum standalone comments - into last statement if it was a simple statement (#18, #28) - -* fixed missing space in numpy-style array indexing (#33) - -* fixed spurious space after star-based unary expressions (#31) - - -### 18.3a1 - -* added `--check` - -* only put trailing commas in function signatures and calls if it's - safe to do so. If the file is Python 3.6+ it's always safe, otherwise - only safe if there are no `*args` or `**kwargs` used in the signature - or call. (#8) - -* fixed invalid spacing of dots in relative imports (#6, #13) - -* fixed invalid splitting after comma on unpacked variables in for-loops - (#23) - -* fixed spurious space in parenthesized set expressions (#7) - -* fixed spurious space after opening parentheses and in default - arguments (#14, #17) - -* fixed spurious space after unary operators when the operand was - a complex expression (#15) - - -### 18.3a0 - -* first published version, Happy 🍰 Day 2018! - -* alpha quality +## Authors -* date-versioned (see: https://calver.org/) +The author list is quite long nowadays, so it lives in its own file. +See [AUTHORS.md](./AUTHORS.md) -## Authors +## Code of Conduct -Glued together by [Łukasz Langa](mailto:lukasz@langa.pl). +Everyone participating in the _Black_ project, and in particular in the issue tracker, +pull requests, and social media activity, is expected to treat other people with respect +and more generally to follow the guidelines articulated in the +[Python Community Code of Conduct](https://www.python.org/psf/codeofconduct/). -Maintained with [Carol Willing](mailto:carolcode@willingconsulting.com) -and [Carl Meyer](mailto:carl@oddbird.net). +At the same time, humor is encouraged. In fact, basic familiarity with Monty Python's +Flying Circus is expected. We are not savages. -Multiple contributions by: -* [Artem Malyshev](mailto:proofit404@gmail.com) -* [Daniel M. Capella](mailto:polycitizen@gmail.com) -* [Eli Treuherz](mailto:eli.treuherz@cgi.com) -* Hugo van Kemenade -* [Mika⠙](mailto:mail@autophagy.io) -* [Osaetin Daniel](mailto:osaetindaniel@gmail.com) +And if you _really_ need to slap somebody, do it with a fish while dancing.