[Python-Dev] PEP 572 and assert
17.07.18 18:48, Guido van Rossum ????:
> On Tue, Jul 17, 2018 at 8:28 AM, Serhiy Storchaka <storchaka at gmail.com
> <mailto:storchaka at gmail.com>> wrote:
> Should not the assert statement introduce an implicit lexical scope
> for preventing leaking variables?
> I don't see why. As Chris said, side effects in asserts are nothing new
> and this PEP is not the one to do something about it.
This side effect is new. No other expressions that can be used in
asserts leaked local variables before. The only exception is list
comprehensions in Python 2, and this was fixed in Python 3.
We can't make the assignment expression itself creating its own scope,
because this will invalidate its purpose. But the problem with assert
ccould be solved by making assert creating a new lexical scope.
assert expr, msg
could be translated to
if __debug__ and not (lambda: expr)():
if __debug__ and not expr: