See https://www.python.org/dev/peps/pep-0505/
On 26 March 2018 at 14:56, Cammil Taank <cta...@gmail.com> wrote: > Given the arguments you've raised, I am now inclined to agree with you. > > However, for completeness of the discussion, I want to indicate the primary > intended use case: > > def fn(x=None): > if not x: > x = some_complex_or_runtime_dependent_result() > > For me this appears quite frequently. Admittedly the condition should likely > be `x is None`. > > > On 26 March 2018 at 14:41, Steven D'Aprano <st...@pearwood.info> wrote: >> >> On Mon, Mar 26, 2018 at 01:48:34PM +0100, Cammil Taank wrote: >> > Hi, >> > >> > I find a common idiom in Python is: >> > >> > x = x or 'some other value' >> >> I don't find it very common. I don't think I've ever used it or seen it. >> I've occasionally used: >> >> spam = eggs or 'something' >> >> but mostly I use: >> >> result = function(eggs or 'something') >> >> (and even that is quite unusual). But others may use it more often. >> >> >> > This is highly reminiscent of the problem inplace operators solve. >> >> Not really: the other augmented operators all connect to ordinary >> operators that can be overloaded. But `or` is special, it's a >> short-cutting operator that is treated specially by the interpreter. >> >> And even if x is mutable, there's no way to make this an in-place >> operation. After `x = x or y`, there are only two possibilities: >> >> - x is still a reference to whatever it was before the operation; >> - or x now refers to the same object as y. >> >> So this is very different behaviour to (say) += and the other augmented >> operators. >> >> >> > Would it be a good idea to consider an inplace operator for this, >> > perhaps: >> > >> > x or= 'some other value' >> >> Mixing a keyword with a symbol like that looks really weird. >> >> Others may disagree, but to me, this pattern isn't common enough to >> justify specialist syntax. I might be a little less negative if the >> syntax didn't look so strange to me. >> >> But only a little. >> >> >> -- >> Steve >> _______________________________________________ >> Python-ideas mailing list >> Python-ideas@python.org >> https://mail.python.org/mailman/listinfo/python-ideas >> Code of Conduct: http://python.org/psf/codeofconduct/ > > > > _______________________________________________ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/ > _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
