try..except with empty exceptions

Rustom Mody rustompmody at gmail.com
Sat Apr 11 06:17:21 CEST 2015


On Saturday, April 11, 2015 at 9:17:16 AM UTC+5:30, Dave Angel wrote:
> On 04/10/2015 10:38 PM, Rustom Mody wrote:
> > On Saturday, April 11, 2015 at 7:53:31 AM UTC+5:30, Dave Angel wrote:
> >> On 04/10/2015 09:42 PM, Steven D'Aprano wrote:
> >>> On Sat, 11 Apr 2015 05:31 am, sohcahtoa82 wrote:
> >>>
> >>>> It isn't document because it is expected.  Why would the exception get
> >>>> caught if you're not writing code to catch it?  If you write a function
> >>>> and pass it a tuple of exceptions to catch, I'm not sure why you would
> >>>> expect it to catch an exception not in the tuple.  Just because the tuple
> >>>> is empty doesn't mean that it should catch *everything* instead.  That
> >>>> would be counter-intuitive.
> >>>
> >>> Really? I have to say, I expected it.
> >>>
> >>>
> >>
> >> I'm astounded at your expectation.  That's like saying a for loop on an
> >> empty list ought to loop on all possible objects in the universe.
> >
> > To work, this analogy should also have two python syntaxes like this:
> >
> > "Normal" for-loop:
> > for var in iterable:
> >    suite
> >
> > "Empty" for-loop:
> > for:
> >    suite
> >
> 
> That tells me nothing about your opinions.  What did you mean by the 
> phrase "to work"?

Your analogy is "for loop on an empty list ought to loop on all possible
objects in the universe"
This seemingly works as a demo of a ridiculous expectation
because there is only one pattern of for-loop
for var in iterable:

In the case of exceptions we have two patterns
except e-tuple:
and
except: 
with the second having a wildly different semantics from the first



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