--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.
+
## 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):
+
+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,
):
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.
## Change Log
-### 18.3a2 (unreleased)
+### 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)