# black
-[](https://travis-ci.org/ambv/black)
+[](https://travis-ci.org/ambv/black)   [](https://github.com/ambv/black)
> Any color you like.
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.
```
+`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*
great.
```py3
# in:
+
l = [1,
2,
3,
]
# out:
+
l = [1, 2, 3]
```
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()]
]
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,
bother you if you overdo it by a few km/h".
+### Empty lines
+
+*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.
+
+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.
+
+
### Editor integration
-There is currently no integration with any text editors. Vim and
+* Visual Studio Code: [joslarson.black-vscode](https://marketplace.visualstudio.com/items?itemName=joslarson.black-vscode)
+
+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.
+
+There is currently no integration with any other text editors. Vim and
Atom/Nuclide integration is planned by the author, others will require
external contributions.
> This vastly improves the formatting of our code. Thanks a ton!
+## Show your style
+
+Use the badge in your project's README.md:
+
+```markdown
+[](https://github.com/ambv/black)
+```
+
+Looks like this: [](https://github.com/ambv/black)
+
+
+
## Tests
Just 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.
+the Python 2 syntax at the same time.
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
## Change Log
+### 18.3a4 (unreleased)
+
+* automatic detection of deprecated Python 2 forms of print statements
+ and exec statements in the formatted file (#49)
+
+* 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)
+
+
### 18.3a3
* don't remove single empty lines outside of bracketed expressions
projects / etc / vim.git / blobdiff