On 6/24/2018 7:25 PM, Guido van Rossum wrote:
I'd wager that the people who might be most horrified about it
the (b) scoping rule change
would be people who feel strongly that the change to the
comprehension scope rules in Python 3 is a big improvement,
I might not be one of those 'most horrified' by (b), but I increasingly don't like it, and I was at best -0 on the comprehension scope change. To me, iteration variable assignment in the current scope is a non-problem. So to me the change was mostly useless churn. Little benefit, little harm. And not worth fighting when others saw a benefit.
However, having made the change to nested scopes, I think we should stick with them. Or repeal them. (I believe there is another way to isolate iteration names -- see below). To me, (b) amounts to half repealing the nested scope change, making comprehensions half-fowl, half-fish chimeras.
Terry Jan Reedy