Coming from Perl, I used to want this badly, but then I thought that there's absolutely nothing wrong with
m = re.match(...)
if m is not None:
pass
Now, I wonder what you meant saying that single-line version is less error-prone, because I don't think so. I believe they're exactly the same in this regard, except for a bizarre case when someone would bastardize the code by putting some irrelevant lines between the assignment and the comparison, obfuscating the logic.
Also, as I tend to use `if m is not None:` rather than just `if m:` (because I typically don't want to run all that subtle `__nonzero__` magic), it would - subjectively - look less pretty in the one-line version: `if (m := re.match(...)) is not None:`.
Use in the generator expressions to create aliases/shortcuts and avoid repetition is great, though. I love this use case.
Also, as I tend to use `if m is not None:` rather than just `if m:` (because I typically don't want to run all that subtle `__nonzero__` magic), it would - subjectively - look less pretty in the one-line version: `if (m := re.match(...)) is not None:`.
Use in the generator expressions to create aliases/shortcuts and avoid repetition is great, though. I love this use case.