X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/4bb7bf2bdc95a8035ccf167023a7044e5f8e5ef6..d4a85643a465f5fae2113d07d22d021d4af4795a:/docs/the_black_code_style/future_style.md diff --git a/docs/the_black_code_style/future_style.md b/docs/the_black_code_style/future_style.md index 8d159e9..17b7eef 100644 --- a/docs/the_black_code_style/future_style.md +++ b/docs/the_black_code_style/future_style.md @@ -23,10 +23,10 @@ So _Black_ will eventually format it like this: ```py3 with \ - make_context_manager(1) as cm1, \ - make_context_manager(2) as cm2, \ - make_context_manager(3) as cm3, \ - make_context_manager(4) as cm4 \ + make_context_manager1() as cm1, \ + make_context_manager2() as cm2, \ + make_context_manager3() as cm3, \ + make_context_manager4() as cm4 \ : ... # backslashes and an ugly stranded colon ``` @@ -34,6 +34,19 @@ with \ Although when the target version is Python 3.9 or higher, _Black_ will use parentheses instead since they're allowed in Python 3.9 and higher. +An alternative to consider if the backslashes in the above formatting are undesirable is +to use {external:py:obj}`contextlib.ExitStack` to combine context managers in the +following way: + +```python +with contextlib.ExitStack() as exit_stack: + cm1 = exit_stack.enter_context(make_context_manager1()) + cm2 = exit_stack.enter_context(make_context_manager2()) + cm3 = exit_stack.enter_context(make_context_manager3()) + cm4 = exit_stack.enter_context(make_context_manager4()) + ... +``` + ## Preview style Experimental, potentially disruptive style changes are gathered under the `--preview` @@ -50,27 +63,92 @@ limit. Line continuation backslashes are converted into parenthesized strings. Unnecessary parentheses are stripped. The stability and status of this feature is tracked in [this issue](https://github.com/psf/black/issues/2188). -### Removing trailing newlines after code block open +### Improved empty line management + +1. _Black_ will remove newlines in the beginning of new code blocks, i.e. when the + indentation level is increased. For example: + + ```python + def my_func(): + + print("The line above me will be deleted!") + ``` + + will be changed to: + + ```python + def my_func(): + print("The line above me will be deleted!") + ``` + + This new feature will be applied to **all code blocks**: `def`, `class`, `if`, + `for`, `while`, `with`, `case` and `match`. + +2. _Black_ will enforce empty lines before classes and functions with leading comments. + For example: + + ```python + some_var = 1 + # Leading sticky comment + def my_func(): + ... + ``` + + will be changed to: + + ```python + some_var = 1 -_Black_ will remove trailing newlines after code block openings. That means that the -following code: + + # Leading sticky comment + def my_func(): + ... + ``` + +### Improved parentheses management + +_Black_ will format parentheses around return annotations similarly to other sets of +parentheses. For example: ```python -def my_func(): +def foo() -> (int): + ... - print("The line above me will be deleted!") +def foo() -> looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong: + ... +``` + +will be changed to: + +```python +def foo() -> int: + ... - print("But the line above me won't!") + +def foo() -> ( + looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong +): + ... ``` -Will be changed to: +And, extra parentheses in `await` expressions and `with` statements are removed. For +example: ```python -def my_func(): - print("The line above me will be deleted!") +with ((open("bla.txt")) as f, open("x")): + ... - print("But the line above me won't!") +async def main(): + await (asyncio.sleep(1)) ``` -This new feature will be applied to **all code blocks**: `def`, `class`, `if`, `for`, -`while`, `with`, `case` and `match`. +will be changed to: + +```python +with open("bla.txt") as f, open("x"): + ... + + +async def main(): + await asyncio.sleep(1) +```