[Python-Dev] PEP 409 update [was: PEP 409 - final?]

[Yury Selivanov]

Re "raise ValueError from ..."

So what does it mean now?  Just resetting __cause__ to make __context__ printed?  Can you show the down-to-earth snippet of code where such syntax would be useful?

Speaking of Zen of Python - I think this stuff contradicts with it more than it follows.

On 2012-02-02, at 10:43 PM, Ethan Furman wrote:

> Tim Delaney wrote:
>> In that case, would the best syntax be:
>>    raise Exception() from Ellipsis
>> or:
>>    raise Exception() from ...
>> ? I kinda like the second - it feels more self-descriptive to me than "from Ellipsis" - but there's the counter-argument that it could look like noise, and I think would require a grammar change to allow it there.
> 
>    raise Exception() from ...
> 
> is... well, I am now gleeful --  especially since I went to my fresh copy of Python 3.3.0a0 and did this:
> 
> --> ...
> Ellipsis
> 
> --> raise ValueError from ...
> Traceback (most recent call last):
>  File "<stdin>", line 1, in <module>
> ValueError
> 
> Have I said lately how much I *love* Python?
> 
> ~Ethan~
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