]> git.madduck.net Git - etc/vim.git/blobdiff - docs/the_black_code_style/future_style.md

madduck's git repository

Every one of the projects in this repository is available at the canonical URL git://git.madduck.net/madduck/pub/<projectpath> — see each project's metadata for the exact URL.

All patches and comments are welcome. Please squash your changes to logical commits before using git-format-patch and git-send-email to patches@git.madduck.net. If you'd read over the Git project's submission guidelines and adhered to them, I'd be especially grateful.

SSH access, as well as push access can be individually arranged.

If you use my repositories frequently, consider adding the following snippet to ~/.gitconfig and using the third clone URL listed for each project:

[url "git://git.madduck.net/madduck/"]
  insteadOf = madduck:

Upgrade isort (#3534)
[etc/vim.git] / docs / the_black_code_style / future_style.md
index 8d159e9b0a21cf0890934b56f48e8f1931901ca6..7a0b2d8f07aadf56a39fe289a5e3e9e5fc65235d 100644 (file)
@@ -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
 
@@ -50,27 +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)
+```