X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/eb5d175c9cd3c14a0731f8afd0cc5a18264353e7..e506c46f7b44e788dfd279e9a474af83e4e03eca:/docs/the_black_code_style/future_style.md?ds=sidebyside diff --git a/docs/the_black_code_style/future_style.md b/docs/the_black_code_style/future_style.md index fab4bca..b2cdca2 100644 --- a/docs/the_black_code_style/future_style.md +++ b/docs/the_black_code_style/future_style.md @@ -19,20 +19,33 @@ with make_context_manager1() as cm1, make_context_manager2() as cm2, make_contex ... # nothing to split on - line too long ``` -So _Black_ will eventually format it like this: +So _Black_ will, when we implement this, 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 ``` -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. +Although when the target version is Python 3.9 or higher, _Black_ uses parentheses +instead in `--preview` mode (see below) 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 @@ -50,71 +63,51 @@ 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 newlines in the beginning of code blocks +### Improved line breaks -_Black_ will remove newlines in the beginning of new code blocks, i.e. when the -indentation level is increased. For example: +For assignment expressions, _Black_ now prefers to split and wrap the right side of the +assignment instead of left side. For example: ```python -def my_func(): - - print("The line above me will be deleted!") +some_dict[ + "with_a_long_key" +] = some_looooooooong_module.some_looooooooooooooong_function_name( + first_argument, second_argument, third_argument +) ``` will be changed to: ```python -def my_func(): - print("The line above me will be deleted!") +some_dict["with_a_long_key"] = ( + some_looooooooong_module.some_looooooooooooooong_function_name( + first_argument, second_argument, third_argument + ) +) ``` -This new feature will be applied to **all code blocks**: `def`, `class`, `if`, `for`, -`while`, `with`, `case` and `match`. - ### Improved parentheses management -_Black_ will format parentheses around return annotations similarly to other sets of -parentheses. For example: - -```python -def foo() -> (int): - ... - -def foo() -> looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong: - ... -``` - -will be changed to: - -```python -def foo() -> int: - ... - - -def foo() -> ( - looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong -): - ... -``` - -And, extra parentheses in `await` expressions and `with` statements are removed. For -example: +For dict literals with long values, they are now wrapped in parentheses. Unnecessary +parentheses are now removed. For example: ```python -with ((open("bla.txt")) as f, open("x")): - ... - -async def main(): - await (asyncio.sleep(1)) +my_dict = { + my_dict = { + "a key in my dict": a_very_long_variable + * and_a_very_long_function_call() + / 100000.0, + "another key": (short_value), +} ``` will be changed to: ```python -with open("bla.txt") as f, open("x"): - ... - - -async def main(): - await asyncio.sleep(1) +my_dict = { + "a key in my dict": ( + a_very_long_variable * and_a_very_long_function_call() / 100000.0 + ), + "another key": short_value, +} ```