(original) (raw)
\[Serhiy Storchaka\]
> Sorry, this PEP was rewritten so many times that I missed your> \[Tim's\] Appendix.
>
>> while total != (total := total + term):
>> term \*= mx2 / (i\*(i+1))
>> i += 2
>> return total
>
> This code looks clever that the original while loop with a break in a
> middle. I like clever code. But it needs more mental efforts for
> understanding it.
>
> I admit that this is a good example.
>
> There is a tiny problem with it (and with rewriting a while loop as a
> for loop, as I like). Often the body contains not a single break. In
> this case the large part of cleverness is disappeared. :-(
[Ivan Pozdeev]
> It took me a few minutes to figure out that this construct actually
> checks term == 0.
> So, this example abuses the construct to do something it's not designed
> to do: perform an unrelated operation before checking the condition.
> (Cue attempts to squeeze ever mode code here.) I would fail it in review.
> This "clever" code is exactly what Perl burned itself on and what
> Python, being its antithesis, was specifically designed to avoid.
So you didn't read the PEP Appendix at all, and Serhiy did but apparently skipped reading what the PEP \_said\_ about that example. It was clearly identified as abuse: a case in which using assignment expressions made the code significantly WORSE. I gave examples of both "wins" and "losses" while staring at real code - I wasn't searching for "proof" that a pre-determined conclusion was justified.
So I wholly agree with you (Ivan) about that example - and that it struck Serhiy as a good example convinces me more than before that there's no overlap in the ways Serhiy and I view this part of the world ;-)
>
> So, this example abuses the construct to do something it's not designed
> to do: perform an unrelated operation before checking the condition.
> (Cue attempts to squeeze ever mode code here.) I would fail it in review.
>
> This "clever" code is exactly what Perl burned itself on and what
> Python, being its antithesis, was specifically designed to avoid.
So you didn't read the PEP Appendix at all, and Serhiy did but apparently skipped reading what the PEP \_said\_ about that example. It was clearly identified as abuse: a case in which using assignment expressions made the code significantly WORSE. I gave examples of both "wins" and "losses" while staring at real code - I wasn't searching for "proof" that a pre-determined conclusion was justified.
So I wholly agree with you (Ivan) about that example - and that it struck Serhiy as a good example convinces me more than before that there's no overlap in the ways Serhiy and I view this part of the world ;-)