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

[Giampaolo Rodola']

On Sun, Jul 22, 2018 at 3:55 AM Steven D'Aprano <steve at pearwood.info> wrote:

> Indeed we do. But we also say:
>
> - we say "+" instead of "add"
> - we say "//" instead of "floor division"
> - we say "**" instead of "exponentiation"
> - we say "&" instead of "bitwise AND"
> - we say "f( ... )" instead of "call f with arguments ..."

[...]

I don't think that "+" is harder to read than

"standard_mathematics_operators_numeric_addition"


Please let's drop the argument that + - * / = and ? are the same. They
clearly are not. Anybody learned those symbols at elementary schools, all
programming languages have them and using math in programming is common
enough to justify a symbol over a keyword. "a + b" is literally just an
addition and nothing else. The "?" variants have multiple meanings,
spellings and implications:

- "a ?? b" means "b is chosen over a if a is None"

- "a ??= b" means "a is set to b if a is None"

- "a?.b" means "a.b is executed but only if a is not None"

- "a?[2] ?? 3" means "index 2 of list a is picked up if a is not None, else
use 3"

"a?.b"and "a?[2]" in particular go way beyond the mere "it's not pretty"
argument which, I concur, can be subjective, as you don't know where
evaluation stops. Even "a ??= b" goes beyond that as it introduces yet
another assignment operator (the third, as we now have = and :=). So again,
I don't think it's fair to dismiss the whole thing as "it's just another
symbol" or "it's like a + b".

As for bitwise operators: they are kinda obscure and low-levelish and when
I bump into them I still have to pause to reason what's going on. The
difference with ? though is that you basically have no other way to do the
same thing. Also they are much more rare and also are present in many other
languages since... forever.

-- 
Giampaolo - http://grodola.blogspot.com
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