Format subscriptions in a PEP-8 compliant way (#178)

[etc/vim.git] / README.md

diff --git a/README.md b/README.md
index bc8977b7a9acff4b8a2a1de39b7abb49f3183fb2..31f92c91f14ab3f5f47af15bd561aa4b0994f148 100644 (file)
--- a/README.md
+++ b/README.md
@@ -302,6 +302,19 @@ This behaviour may raise ``W503 line break before binary operator`` warnings in
 style guide enforcement tools like Flake8. Since ``W503`` is not PEP 8 compliant,
 you should tell Flake8 to ignore these warnings.
 
+### Slices
+
+PEP 8 [recommends](https://www.python.org/dev/peps/pep-0008/#whitespace-in-expressions-and-statements)
+to treat ``:`` in slices as a binary operator with the lowest priority, and to
+leave an equal amount of space on either side, except if a parameter is omitted
+(e.g. ``ham[1 + 1 :]``). It also states that for extended slices, both ``:``
+operators have to have the same amount of spacing, except if a parameter is
+omitted (``ham[1 + 1 ::]``). *Black* enforces these rules consistently.
+
+This behaviour may raise ``E203 whitespace before ':'`` warnings in style guide
+enforcement tools like Flake8. Since ``E203`` is not PEP 8 compliant, you should
+tell Flake8 to ignore these warnings.
+
 ### Parentheses
 
 Some parentheses are optional in the Python grammar.  Any expression can