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

[Rhodri James]

On 28/07/18 21:07, Abe Dillon wrote:
[>> = Me]
>> We could argue about how intuitive or not these operators are, but they
>> are used in other languages, so they clearly aren't completely unintuitive.
> 
> Other languages are other languages. Other languages use the "<condition> ?
> <expr_a> : <expr_b>" form of the the ternary operator. That doesn't mean we
> should adopt that into Python.

But it does and did mean that we should consider it when coming up with 
Python's version of the ternary operator.  *It isn't unintuitive* and 
neither is ??  None-aware operators may be bad for other reasons, but 
that argument doesn't wash.

>> Really?  Quick straw poll: how often do people care how in-place operators
>> are implemented?
> 
> The point I was trying to make is that it doesn't behave or compose like
> other expressions.

(This was about ??=, for context.)  Pardon?  It composes exactly like 
any other in-place operator.

[Abe previously wrote:]
 >>> val = person[0]?
 >>> val = person.name?
 >>
>> Um.  How is that supposed to parse?  "person[0]" has already been evaluated
>> by the time the "?" operator gets anywhere near it.
> 
> It parses by placing the '?' operator high in the order of operations; like
> I said. Do I really need to explain how order of operations works?

Apology elsewhere accepted, but yes, you do need to explain how merely 
being high precedence helps here.  Let's start small; please explain 
programmatically what

   name?

does as an expression.  Once we have that down, we can move on to

   person.(name?)

(parentheses for emphasis.)  Short of actual magic, I can't see how this 
is going to work.

-- 
Rhodri James *-* Kynesim Ltd