[Python-Dev] Re: Accepting PEP 584: Add Union Operators To dict

Maybe it's more the `a ||= b` that acts like a `a = a or b` in Python? But then I don't think there is a confusion on Python side because languages with a || operator usually already has a simple | with a different meaning. Le jeu. 27 févr. 2020 à 00:28, Nick Coghlan a écrit :

On Thu., 27 Feb. 2020, 2:03 am Guido van Rossum, wrote:

...

On Wed, Feb 26, 2020 at 7:43 AM Claudio Jolowicz wrote:

...

In my experience, the expression `value |= other` is a common idiom across programming languages to provide a default for `value` if it is "unset".

Interesting. Can you point to specific examples of this? In what other languages have you seen this? (Not that it would make us change PEP 584, but if this appears common we could probably warn about it prominently in docs and tutorials.)

I was thinking that bash scripting might be an example, but I double checked, and that's spelled 'VAR="${$VAR:-default value}" '

make has 'VAR ?= "default value"'

C# uses "??=" for null coalescence on assignment.

So I've also never come across "|=" being used for this purpose.

Cheers, Nick.

_______________________________________________ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-leave@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/HMKYUZP5... Code of Conduct: http://python.org/psf/codeofconduct/

-- Antoine Rozo