Is this PEP-able? fwhile

[Ian Kelly]

On Tue, Jun 25, 2013 at 1:21 AM, Chris Angelico <rosuav at gmail.com> wrote:
> On Tue, Jun 25, 2013 at 2:20 PM, Benjamin Kaplan
> <benjamin.kaplan at case.edu> wrote:
>> The reason I was given (which I promptly ignored, of course) is that
>> it's "best practice" to only have one exit point for a block of code.
>> Only one way of terminating your loop, only one "return" per function,
>> never use exceptions, etc. I think it originally came about as a way
>> to make sure that your clean-up code was called (and to make it easier
>> for code reviewers to make sure your clean up code was called) and
>> then started being passed around as a rule among programming teachers
>> who didn't have any experience outside the classroom.
>
> I've heard that "one exit point" rule before, too, but never any
> justification for it. Your explanation does at least make sense
> (albeit only in a language without even RAII), but I don't like silly
> rules like that :)

In my experience the sorts of people who preach "one exit point" are
also all about defining preconditions and postconditions and proving
that the postconditions follow from the preconditions.  I think that
the two are linked, because the "one exit point" rule makes those
sorts of proofs simpler.