[Python-ideas] PEP 505: None-aware operators

[Nicholas Chammas]

On Wed, Jul 25, 2018 at 9:20 PM Chris Angelico <rosuav at gmail.com> wrote:

> On Thu, Jul 26, 2018 at 11:02 AM, David Mertz <mertz at gnosis.cx> wrote:
> > That is disingenuous, I think.  Can this raise an AttributeError?
> >
> >     spam?.eggs?.bacon
> >
> > Of course it can! And this is exactly the pattern used in many examples
> in
> > the PEP and the discussion. So the PEP would create a situation where
> code
> > will raise AttributeError in a slightly—and subtly—different set of
> > circumstances than plain attribute access will.
>
> I don't understand. If it were to raise AttributeError, it would be
> because spam (or spam.eggs) isn't None, but doesn't have an attribute
> eggs (or bacon). Exactly the same as regular attribute access. How is
> it slightly different? Have I missed something?
>

That was my reaction, too.

    food = spam?.eggs?.bacon

Can be rewritten as:

    food = spam
    if spam is not None and spam.eggs is not None:
        food = spam.eggs.bacon

They both behave identically, no? Maybe I missed the point David was trying
to make.
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