Add DebugVisitor.show() to documentation under utility functions

[etc/vim.git] / README.md

diff --git a/README.md b/README.md
index b3e69851965c409d0ec1c0ab24c712f597bde368..ac4caa19414773bf97caca88a6904f4302e3d0aa 100644 (file)
--- a/README.md
+++ b/README.md
@@ -1,8 +1,16 @@
-# black
+![Black Logo](https://raw.githubusercontent.com/ambv/black/master/docs/_static/logo2-readme.png)
+<h2 align="center">The Uncompromising Code Formatter</h2>

 
 

-[![Build Status](https://travis-ci.org/ambv/black.svg?branch=master)](https://travis-ci.org/ambv/black)
+<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="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"><img alt="Code style: black" src="https://img.shields.io/badge/code%20style-black-000000.svg"></a>
+</p>

 
 

-> Any color you like.
+> “Any color you like.”

 
 
 *Black* is the uncompromising Python code formatter.  By using it, you
 
 
 *Black* is the uncompromising Python code formatter.  By using it, you


@@ -19,43 +27,68 @@ content instead.
 possible.
 
 
 possible.
 
 

-## NOTE: This is an early pre-release
+## Installation and Usage

 
 

-*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**.
+### Installation

 
 

-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``.
+*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.

 
 
 
 

-## Usage
+### Usage

 
 

-*Black* can be installed by running `pip install black`.
+To get started right away with sensible defaults:

 
 ```
 
 ```

+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
 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 changed.
-                              Return code 1 means some files were reformatted.
-                              Return code 123 means there was an internal
-                              error.
+                              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.
 ```
 
   --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).

 
 

-## The philosophy behind *Black*
+
+### 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
 
 *Black* reformats entire files in place.  It is not configurable.  It
 doesn't take previous formatting into account.  It doesn't reformat


@@ -64,24 +97,27 @@ recognizes [YAPF](https://github.com/google/yapf)'s block comments to
 the same effect, as a courtesy for straddling code.
 
 
 the same effect, as a courtesy for straddling code.
 
 

-### How *Black* formats files
+### 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
 
 *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.
+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:
 
 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:

+

 l = [1,
      2,
      3,
 ]
 
 # out:
 l = [1,
      2,
      3,
 ]
 
 # out:

+

 l = [1, 2, 3]
 ```
 
 l = [1, 2, 3]
 ```
 


@@ -89,9 +125,11 @@ If not, *Black* will look at the contents of the first outer matching
 brackets and put that in a separate indented line.
 ```py3
 # in:
 brackets and put that in a separate indented line.
 ```py3
 # in:

+

 l = [[n for n in list_bosses()], [n for n in list_employees()]]
 
 # out:
 l = [[n for n in list_bosses()], [n for n in list_employees()]]
 
 # out:

+

 l = [
     [n for n in list_bosses()], [n for n in list_employees()]
 ]
 l = [
     [n for n in list_bosses()], [n for n in list_employees()]
 ]


@@ -106,16 +144,17 @@ matching brackets.  If that doesn't work, it will put all of them in
 separate lines.
 ```py3
 # in:
 separate lines.
 ```py3
 # in:

-def very_important_function(template: str, *variables, *, file: os.PathLike, debug: bool = False):
+
+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:
     """Applies `variables` to the `template` and writes to `file`."""
     with open(file, 'w') as f:
         ...
 
 # out:

+

 def very_important_function(
     template: str,
     *variables,
 def very_important_function(
     template: str,
     *variables,

-    *,

     file: os.PathLike,
     debug: bool = False,
 ):
     file: os.PathLike,
     debug: bool = False,
 ):


@@ -132,20 +171,6 @@ 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).
 
 indentation level (like the arguments list and the docstring in the
 example above).
 

-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.
-
-*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.
-
-That's it.  The rest of the whitespace formatting rules follow PEP 8 and
-are designed to keep `pycodestyle` quiet.
-

 
 ### Line length
 
 
 ### Line length
 


@@ -184,14 +209,124 @@ 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".
 
 
 bother you if you overdo it by a few km/h".
 
 

-### Editor integration
+### Empty lines
+
+*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.
+
+*Black* will allow single empty lines inside functions, and single and
+double empty lines on module level left by the original editors, except
+when they're within parenthesized expressions.  Since such expressions
+are always reformatted to fit minimal space, this whitespace is lost.
+
+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.
+
+
+### Trailing commas
+
+*Black* will add trailing commas to expressions that are split
+by comma where each element is on its own line.  This includes function
+signatures.
+
+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.

 
 

-There is currently no integration with any text editors. Vim and
-Atom/Nuclide integration is planned by the author, others will require
-external contributions.
+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, ]```.
+
+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.
+
+
+## Editor integration
+
+### Emacs
+
+Use [proofit404/blacken](https://github.com/proofit404/blacken).
+
+
+### Vim
+
+Commands and shortcuts:
+
+* `,=` or `: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_virtualenv` (defaults to `~/.vim/black`)
+
+To install, copy the plugin from [vim/plugin/black.vim](https://github.com/ambv/black/tree/master/vim/plugin/black.vim).
+Let me know if this requires any changes to work with Vim 8's builtin
+`packadd`, or Pathogen, or Vundle, and so on.
+
+This plugin **requires Vim 7.0+ built with Python 3.6+ support**.  It
+needs Python 3.6 to be able to run *Black* inside the Vim process which
+is much faster than calling an external command.
+
+On first run, the plugin creates its own virtualenv using the right
+Python version and automatically installs *Black*. You can upgrade it later
+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
+create a virtualenv manually and point `g:black_virtualenv` to it.
+The plugin will use it.
+
+**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`.
+When building Vim from source, use:
+`./configure --enable-python3interp=yes`. There's many guides online how
+to do this.
+
+
+### Visual Studio Code
+
+Use [joslarson.black-vscode](https://marketplace.visualstudio.com/items?itemName=joslarson.black-vscode).
+
+
+### Other editors
+
+Atom/Nuclide integration is planned by the author, others will
+require external contributions.

 
 Patches welcome! ✨ 🍰 ✨
 
 
 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)).
+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.
+
+This can be used for example with PyCharm's [File Watchers](https://www.jetbrains.com/help/pycharm/file-watchers.html).
+

 
 ## Testimonials
 
 
 ## Testimonials
 


@@ -214,25 +349,15 @@ and [`pipenv`](https://docs.pipenv.org/):
 > This vastly improves the formatting of our code. Thanks a ton!
 
 
 > This vastly improves the formatting of our code. Thanks a ton!
 
 

-## Tests
+## Show your style

 
 

-Just run:
+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)

 ```
 ```

-python setup.py test
-```
-
-## This tool requires Python 3.6.0+ to run

 
 

-But you can reformat Python 2 code with it, too.  *Black* is able to parse
-all of the new syntax supported on Python 3.6 but also *effectively all*
-the Python 2 syntax at the same time, as long as you're not using print
-statements.
-
-By making the code exclusively Python 3.6+, I'm able to focus on the
-quality of the formatting and re-use all the nice features of the new
-releases (check out [pathlib](https://docs.python.org/3/library/pathlib.html) or
-f-strings) instead of wasting cycles on Unicode compatibility, and so on.
+Looks like this: [![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)

 
 
 ## License
 
 
 ## License


@@ -240,7 +365,7 @@ f-strings) instead of wasting cycles on Unicode compatibility, and so on.
 MIT
 
 
 MIT
 
 

-## Contributing
+## Contributing to Black

 
 In terms of inspiration, *Black* is about as configurable as *gofmt* and
 *rustfmt* are.  This is deliberate.
 
 In terms of inspiration, *Black* is about as configurable as *gofmt* and
 *rustfmt* are.  This is deliberate.


@@ -253,13 +378,90 @@ 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.
 
 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
 
 
 ## Change Log
 

+### 18.3a5 (unreleased)
+
+* fixed 18.3a4 regression: don't crash and burn on empty lines with
+  trailing whitespace (#80)
+
+* only allow up to two empty lines on module level and only single empty
+  lines within functions (#74)
+
+
+### 18.3a4
+
+* `# fmt: off` and `# fmt: on` are implemented (#5)
+
+* automatic detection of deprecated Python 2 forms of print statements
+  and exec statements in the formatted file (#49)
+
+* use proper spaces for complex expressions in default values of typed
+  function arguments (#60)
+
+* 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`
 
 ### 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
 * fixed invalid spacing of dots in relative imports (#6, #13)
 
 * fixed invalid splitting after comma on unpacked variables in for-loops


@@ -286,3 +488,14 @@ You can still try but prepare to be disappointed.
 ## Authors
 
 Glued together by [Łukasz Langa](mailto:lukasz@langa.pl).
 ## Authors
 
 Glued together by [Łukasz Langa](mailto:lukasz@langa.pl).

+
+Maintained with [Carol Willing](mailto:carolcode@willingconsulting.com)
+and [Carl Meyer](mailto:carl@oddbird.net).
+
+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)