Re: Whether to raise exception or End_of_List function

[Ed Falis <efalis@mediaone.net>]

Larry Kilgallen wrote:
> 
> In article <slrn9vnh96.55u.randhol+abuse@kiuk0156.chembio.ntnu.no>, Preben Randhol <randhol+abuse@pvv.org> writes:
> 
> > My question is which is the better solution; Exception or a End_of_List
> > function and which would have fewer side effects?
> 
> Exceptions are supposed to be rare events.  In many applications
> reaching the end of a list is fully expected and not necessarily
> rare.
> 
> Exception processing can take significant overhead, since compiler
> implementors know it will be rare.

Personally, I'm inclined to follow the Eiffel DbC style by stating the
conditions for calling any routine, and those that are guaranteed on
return, rather than using exception processing as part of the normal
execution of the routine.  By using pragma Assert (available at least on
GNAT and the Averstar-based compilers), you can enable the assertions
during development, then turn them off for production.

- Ed