X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/04bce6ad2ecf38656149fd261f01f84699cf0b6a..b8e2ec728cc09d0f00829a9cffcb54da3efa5760:/docs/the_black_code_style/current_style.md diff --git a/docs/the_black_code_style/current_style.md b/docs/the_black_code_style/current_style.md index 3db49e2..0fb59fe 100644 --- a/docs/the_black_code_style/current_style.md +++ b/docs/the_black_code_style/current_style.md @@ -140,6 +140,8 @@ If you're reaching for backslashes, that's a clear signal that you can do better slightly refactor your code. I hope some of the examples above show you that there are many ways in which you can do it. +(labels/line-length)= + ### Line length You probably noticed the peculiar default line length. _Black_ defaults to 88 characters @@ -158,33 +160,35 @@ harder to work with line lengths exceeding 100 characters. It also adversely aff side-by-side diff review on typical screen resolutions. Long lines also make it harder to present code neatly in documentation or talk slides. -If you're using Flake8, you can bump `max-line-length` to 88 and mostly forget about it. -However, it's better if you use [Bugbear](https://github.com/PyCQA/flake8-bugbear)'s -B950 warning instead of E501, and bump the max line length to 88 (or the `--line-length` -you used for black), which will align more with black's _"try to respect -`--line-length`, but don't become crazy if you can't"_. You'd do it like this: - -```ini -[flake8] -max-line-length = 88 -... -select = C,E,F,W,B,B950 -extend-ignore = E203, E501 -``` +#### Flake8 -Explanation of why E203 is disabled can be found further in this documentation. And if -you're curious about the reasoning behind B950, -[Bugbear's documentation](https://github.com/PyCQA/flake8-bugbear#opinionated-warnings) -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". +If you use Flake8, you have a few options: -**If you're looking for a minimal, black-compatible flake8 configuration:** +1. Recommended is using [Bugbear](https://github.com/PyCQA/flake8-bugbear) and enabling + its B950 check instead of using Flake8's E501, because it aligns with Black's 10% + rule. Install Bugbear and use the following config: -```ini -[flake8] -max-line-length = 88 -extend-ignore = E203 -``` + ```ini + [flake8] + max-line-length = 80 + ... + select = C,E,F,W,B,B950 + extend-ignore = E203, E501 + ``` + + The rationale for E950 is explained in + [Bugbear's documentation](https://github.com/PyCQA/flake8-bugbear#opinionated-warnings). + +2. For a minimally compatible config: + + ```ini + [flake8] + max-line-length = 88 + extend-ignore = E203 + ``` + +An explanation of why E203 is disabled can be found in the [Slices section](#slices) of +this page. ### Empty lines @@ -194,7 +198,45 @@ that in-function vertical whitespace should only be used sparingly. _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. +space, this whitespace is lost. The other exception is that it will remove any empty +lines immediately following a statement that introduces a new indentation level. + +```python +# in: + +def foo(): + + print("All the newlines above me should be deleted!") + + +if condition: + + print("No newline above me!") + + print("There is a newline above me, and that's OK!") + + +class Point: + + x: int + y: int + +# out: + +def foo(): + print("All the newlines above me should be deleted!") + + +if condition: + print("No newline above me!") + + print("There is a newline above me, and that's OK!") + + +class Point: + x: int + y: int +``` 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 @@ -235,6 +277,8 @@ A pre-existing trailing comma informs _Black_ to always explode contents of the bracket pair into one item per line. Read more about this in the [Pragmatism](#pragmatism) section below. +(labels/strings)= + ### Strings _Black_ prefers double quotes (`"` and `"""`) over single quotes (`'` and `'''`). It @@ -406,6 +450,11 @@ file that are not enforced yet but might be in a future version of the formatter - use variable annotations instead of type comments, even for stubs that target older versions of Python. +### Line endings + +_Black_ will normalize line endings (`\n` or `\r\n`) based on the first line ending of +the file. + ## Pragmatism Early versions of _Black_ used to be absolutist in some respects. They took after its @@ -414,6 +463,8 @@ there were not many users anyway. Not many edge cases were reported. As a mature _Black_ does make some exceptions to rules it otherwise holds. This section documents what those exceptions are and why this is the case. +(labels/magic-trailing-comma)= + ### The magic trailing comma _Black_ in general does not take existing formatting into account. @@ -450,17 +501,19 @@ default by (among others) GitHub and Visual Studio Code, differentiates between r-strings and R-strings. The former are syntax highlighted as regular expressions while the latter are treated as true raw strings with no special semantics. +(labels/ast-changes)= + ### AST before and after formatting -When run with `--safe`, _Black_ checks that the code before and after is semantically -equivalent. This check is done by comparing the AST of the source with the AST of the -target. There are three limited cases in which the AST does differ: +When run with `--safe` (the default), _Black_ checks that the code before and after is +semantically equivalent. This check is done by comparing the AST of the source with the +AST of the target. There are three limited cases in which the AST does differ: 1. _Black_ cleans up leading and trailing whitespace of docstrings, re-indenting them if needed. It's been one of the most popular user-reported features for the formatter to fix whitespace issues with docstrings. While the result is technically an AST - difference, due to the various possibilities of forming docstrings, all realtime use - of docstrings that we're aware of sanitizes indentation and leading/trailing + difference, due to the various possibilities of forming docstrings, all real-world + uses of docstrings that we're aware of sanitize indentation and leading/trailing whitespace anyway. 1. _Black_ manages optional parentheses for some statements. In the case of the `del`