Add optional chaining of attributes

Ideas
1

Hey everyone!

Other languages have the concept of optional chaining (javascript/swift maybe more). It enables developers to easily access nested attributes that might be null. Example of how it could be used.

from typing import Optional
class B:
    data: Optional[bool]

class A:
    container: Optional[B]

a = A()
if data := a?.container?.data:
    ...

To do something similar today.

try:
    if data := a.container.data:
        ...
except (NameError, AttributeError) as e:
    pass

Is this something to consider as an addition to python or has it already been discussed?

2 Likes
2
5 Likes
3

Maybe it’s worth giving it another go, with a reduced scope? AFAIR the most controversial part was the None aware index access ?[ ]. The ?. and ?? operators do provide quite a lot of value on there own.
?[ ] could always be done at a later point.

2 Likes
4

That’s up to you and/or anyone else who wants to write a new PEP to propose that subset of operators.

1 Like
5

I need to read up on my PEP 1 to move forward with this it seems :slight_smile:

6

As PEP 505 suggests three new operators and that might be a bit much for a single PEP would it be better to create separate PEPs for null coalescing and null aware member access? Or if I move forward with this keep it in a single PEP for these two suggestions?

7

It’s up to you and anyone else who wants to take this on. Since PEP 505 was technically deferred you could ask to be made a co-author and resuscitate the PEP. Otherwise you have to ask yourself if you think a single PEP has a better chance of being accepted than two separate PEPs?

1 Like