Re: [boost] [python] can I stop iteration without exception being thrown?

From: Stefan Seefeld (seefeld_at_[hidden])
Date: 2008-06-11 07:26:12

Bruno Lalande wrote:
>>> Gennadiy Rozental wrote:
>>>       
>>>> This code causes an exception being thrown to stop iteration. I just
>>>> wonder if
>>>> there is means to avoid it.
>>>>
>>>>         
>>> Out of curiosity, what's the problem with code throwing an exception, as
>>> long as it is properly caught ?
>>>       
>> In general? Setting aside potential performance consequences, exceptions have to
>> be used only to report error conditions, not as end of loop indicator.
>>     
>
> Beside the fact that I completely agree with you (but probably because
> I'm a C++ developer), you have to be aware that Python and C++
> philosophies differ dramatically. On this precise point, while C++
> developers are attached to a well-defined balance between return codes
> and exceptions, Python has pushed the use of exceptions to an extreme.
> This often leads to things that are considered as worst practices
> and/or beginner mistakes in other languages, like the fact of stopping
> an iteration by throwing. In Python, the assertion that "exceptions
> should only handle errors" is unfortunately false.
>   

And even in C++...
Wasn't there some discussion on this list a little while ago about using 
exceptions to interrupt tree or graph traversals, being conceptually and 
technically easier than to check after each node for various conditions ?

FWIW,

       Stefan

-- 
      ...ich hab' noch einen Koffer in Berlin...