On Thu, Aug 2, 2018 at 12:04 AM, Jonathan Fine <jfine2358@gmail.com> wrote:
Hi Steve
Thank you for your reply.
We're discussing the abstract to PEP 505, which writes === The "None-aware attribute access" operator ?. ("maybe dot") evaluates the complete expression if the left hand side evaluates to a value that is not None ===
I gave (42).str as an example. I wrote
I don't see how to apply the prose in the abstract to this last example. The left hand side is not None, so we "evaluate the complete expression". On one reading, this is a recursion.
You wrote
The phrasing could be clearer.
I think the phrasing could be considerably improved (see below).
Since 42 is not None, it evaluates (42).str [...]
Based on this hint, here's what I think is a better statement. === Let `lhs` be the value of the left hand side, and RHS the code fragment on the right hand side. If `lhs` is None, then the whole expression is `None`. Otherwise, `lhs . RHS` gives the value of the whole expression. ===
Please would the experts tell me: Is it true? And if true, is it better? And can it be improved?
It may be true, but it isn't better IMO - especially not for the abstract. It's unnecessarily pedantic. The current wording isn't ambiguous, because infinite recursion makes no sense. MAYBE change it to "evaluate the rest of the expression", but I don't see a problem with the current wording. ChrisA