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

[Steven D'Aprano]

On Sun, Jul 29, 2018 at 06:32:19AM -0400, David Mertz wrote:
> On Sun, Jul 29, 2018, 2:00 AM Steven D'Aprano <steve at pearwood.info> wrote:
> 
> > Fine. So it takes them an extra day to learn one more operator. Big
> > deal. It is commonly believed to take ten years to master a field or
> > language. Amortize that one day over ten years and its virtually
> > nothing.
> >
> 
> This is where being wrong matters. The experience in this thread of most
> supporters failing to get the semantics right shows that this isn't an
> extra day to learn.

The difficulty one or two people had in coming up with a correct 
equivalent to none-aware operators on the spur of the moment is simply 
not relevant. Aside from whichever developers implements the feature, 
the rest of us merely *use* it, just as we already use import, 
comprehensions, yield from, operators, class inheritence, and other 
features which are exceedingly difficult to emulate precisely in pure 
Python code.

Even something as simple as the regular dot attribute lookup is 
difficult to emulate precisely. I doubt most people would be able to 
write a pure-Python version of getattr correctly the first time. Or even 
the fifth. I know I wouldn't.

I'm sure that you are fully aware that if this proposal is accepted, 
people will not need to reinvent the wheel by emulating these none-aware 
operators in pure Python, so your repeated argument that (allegedly) 
even the supporters can't implement it correctly is pure FUD. They won't 
have to implement it, that's the point.


-- 
Steve