[Python-Dev] PEP 572: Assignment Expressions

[Steven D'Aprano]

On Mon, Apr 23, 2018 at 03:36:10PM -0700, Guido van Rossum wrote:
> Using 'as' was debated extensively on python-ideas. I don't like it for
> several reasons:
[...]

For what it is worth, I was one of the original proponents of the "as" 
syntax, but at this point I am no longer going to argue for it. I'm 
satisfied that using "as" has disadvantages, and that := is an 
acceptable alternative.

While I haven't changed my mind that putting the expression first and 
the target second is better, I'm satisfied that it is not so much better 
that it is worth extending this enormous discussion even further.

In other words, as far as I am concerned, I am happy to take the syntax 
as decided: "expr as name" is rejected and "name := expr" is acceptable.

I'm also satisfied that *at least for now* we should stick to only 
allowing simple names. We can always loosen the restriction later and 
allow arbitrarily complex targets at a later date, but we can't easily 
change our mind and prohibit them.



-- 
Steve