[boost] Re: Exceptions as streams

From: Jonathan Turkanis (technews_at_[hidden])
Date: 2004-02-09 23:00:38

"Geoff Leyland" <gley001_at_[hidden]> wrote in message
news:F830594E-5B79-11D8-B48C-000A95DB9BF6_at_ec.auckland.ac.nz...
> On 10/02/2004, at 2:36 PM, Jonathan Turkanis wrote:
>
> > Are you proposing a single new exception which overloads
operator<<,
> > for use in testing, or are you thinking of using it as a framework
for
> > user-define exceptions in situations where the programmer judges
that
> > low resources will not  be a problem?
>
> Well, I have a use case in which it helps me, which I explained in
the
> last post - and I can explain further if you like - and perhaps
there
> are others.
>
> I think that for testing and correctness Boost.Test type things and
and
> assertions are the right tools.
>
> I guess I am using it in a case:
>    where I judge that low resources will not be a problem;
>    where, if an another exception occurs in generating the
exception,
> well, bummer;
>    where it's not worth spending time on a nicer mechanism;
>    where I would like a semi-explanatory error message to be printed
on
> the console or saved;
>    where I do want the option of continuing with something (the next
> test), but I'm not really interested in rectifying the error.
>
> In my particular case, as I said, the errors usually come from the
user
> not getting an input file quite right (parseable, but not containing
> all the information I later need)

I got that part. I agree that there are times when the convenience of
using strings (or streams) might outweigh the other disadvantages we
discussed. But I think people trying to write reusable code will be
reluctant to define exceptions that are only appropriate for limited
circumstances. After all, part of the justification for introducing
exceptions was that code which is in a position to detect errors often
does not how to handle them appropriately, and some of the conditions
you mention above sound like judgement that the programmer trying to
handle exceptions might be in a better to make than the programmer wri
ting the code which throws the exceptions.

For small programs written by one person these issues are not so
important. (These are also the cases where you can get away with
thowing int or const char* ;-)

Best Regards,
Jonathan