X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/2da2c15b2140c453abdf1487782ab700add83d67..f6393a20fc0f382c6bab545f8f60ec8e10d5e099:/README.md diff --git a/README.md b/README.md index 6970a2a..5bf6f06 100644 --- a/README.md +++ b/README.md @@ -148,7 +148,7 @@ about _Black_'s changes or will overwrite _Black_'s changes. A good example of t should be configured to neither warn about nor overwrite _Black_'s changes. Actual details on _Black_ compatible configurations for various tools can be found in -[compatible_configs](./docs/compatible_configs.md). +[compatible_configs](https://github.com/psf/black/blob/master/docs/compatible_configs.md). ### NOTE: This is a beta product @@ -238,6 +238,69 @@ def very_important_function( ... ``` +_Black_ prefers parentheses over backslashes, and will remove backslashes if found. + +```py3 +# in: + +if some_short_rule1 \ + and some_short_rule2: + ... + +# out: + +if some_short_rule1 and some_short_rule2: + ... + + +# in: + +if some_long_rule1 \ + and some_long_rule2: + ... + +# out: + +if ( + some_long_rule1 + and some_long_rule2 +): + ... + +``` + +Backslashes and multiline strings are one of the two places in the Python grammar that +break significant indentation. You never need backslashes, they are used to force the +grammar to accept breaks that would otherwise be parse errors. That makes them confusing +to look at and brittle to modify. This is why _Black_ always gets rid of them. + +If you're reaching for backslashes, that's a clear signal that you can do better if you +slightly refactor your code. I hope some of the examples above show you that there are +many ways in which you can do it. + +However there is one exception: `with` statements using multiple context managers. +Python's grammar does not allow organizing parentheses around the series of context +managers. + +We don't want formatting like: + +```py3 +with make_context_manager1() as cm1, make_context_manager2() as cm2, make_context_manager3() as cm3, make_context_manager4() as cm4: + ... # nothing to split on - line too long +``` + +So _Black_ will now 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 \ +: + ... # backslashes and an ugly stranded colon +``` + You might have noticed that closing brackets are always dedented and that a trailing comma is always added. Such formatting produces smaller diffs; when you add or remove an element, it's always just one line. Also, having the closing bracket dedented provides a @@ -823,6 +886,55 @@ default. On macOS with Homebrew run: `brew install vim`. When building Vim from use: `./configure --enable-python3interp=yes`. There's many guides online how to do this. +**I get an import error when using _Black_ from a virtual environment**: If you get an +error message like this: + +```text +Traceback (most recent call last): + File "", line 63, in + File "/home/gui/.vim/black/lib/python3.7/site-packages/black.py", line 45, in + from typed_ast import ast3, ast27 + File "/home/gui/.vim/black/lib/python3.7/site-packages/typed_ast/ast3.py", line 40, in + from typed_ast import _ast3 +ImportError: /home/gui/.vim/black/lib/python3.7/site-packages/typed_ast/_ast3.cpython-37m-x86_64-linux-gnu.so: undefined symbool: PyExc_KeyboardInterrupt +``` + +Then you need to install `typed_ast` and `regex` directly from the source code. The +error happens because `pip` will download [Python wheels](https://pythonwheels.com/) if +they are available. Python wheels are a new standard of distributing Python packages and +packages that have Cython and extensions written in C are already compiled, so the +installation is much more faster. The problem here is that somehow the Python +environment inside Vim does not match with those already compiled C extensions and these +kind of errors are the result. Luckily there is an easy fix: installing the packages +from the source code. + +The two packages that cause the problem are: + +- [regex](https://pypi.org/project/regex/) +- [typed-ast](https://pypi.org/project/typed-ast/) + +Now remove those two packages: + +```console +$ pip uninstall regex typed-ast -y +``` + +And now you can install them with: + +```console +$ pip install --no-binary :all: regex typed-ast +``` + +The C extensions will be compiled and now Vim's Python environment will match. Note that +you need to have the GCC compiler and the Python development files installed (on +Ubuntu/Debian do `sudo apt-get install build-essential python3-dev`). + +If you later want to update _Black_, you should do it like this: + +```console +$ pip install -U black --no-binary regex,typed-ast +``` + ### Visual Studio Code Use the @@ -1073,13 +1185,14 @@ other hand, if your answer is "because I don't like a particular formatting" the not ready to embrace _Black_ yet. Such changes are unlikely to get accepted. You can still try but prepare to be disappointed. -More details can be found in [CONTRIBUTING](CONTRIBUTING.md). +More details can be found in +[CONTRIBUTING](https://github.com/psf/black/blob/master/CONTRIBUTING.md). ## Change Log The log's become rather long. It moved to its own file. -See [CHANGES](CHANGES.md). +See [CHANGES](https://github.com/psf/black/blob/master/CHANGES.md). ## Authors