[Python-ideas] Fwd: Null coalescing operator

[Eric Snow]

On Mon, Sep 12, 2016 at 3:13 PM, Paul Moore <p.f.moore at gmail.com> wrote:
> From previous explanations in this thread, that's *not* the behaviour at all.

Gah, you're right.  I knew better too.  The diversion back to PEP 463
crossed some wires in my brain. :)

>
> If I understand the proposal, f is actually intended to be equivalent to:
>
>     def f(spam):
>         spam_val = spam()
>         if spam_val is None:
>             return None
>         eggs_val = spam_val.eggs()
>         if eggs_val is None:
>             return None
>         return eggs_val.ham

...which is even less related to PEP 463.

>
> Personally, I find it pretty worrying that there's this persistent
> confusion over what the proposed syntax means. Sure, it's explained in
> the PEP and proposal, but if it gets implemented it'll be in the docs.
> And yet people don't seem to read any of those - and their intuition
> of what the construct does is wrong.

The tricky bit is the syntactic association with attribute lookup.
However, I don't think it's quite so confusing.  As noted above, my
confusion was mostly due to the recent mention of PEP 463.

-eric