Re: [boost] [review] Review of Exception begins today

From: Gennadiy Rozental (rogeeff_at_[hidden])
Date: 2007-10-03 19:38:36

Tobias Schwinger <tschwinger <at> isonews2.com> writes:

> 
> Emil Dotchevski wrote:
> >> I'm not keen on the use of operator<< to add the data to the exceptions.
> > 
> > I do share your concern, but consider that whatever we use for boost
> > exception should support easy composition, because it needs to work
> > when used in a throw expression directly:
> > 
> > throw my_error() <<
> >     error_info<tag_errno>(errno) <<
> >     error_info<tag_name>(name);
> > 
> > Instead of << we could use .add:
> > 
> > throw my_error().
> >     add(error_info<tag_errno>(errno)).
> >     add(error_info<tag_name>(name));
> > 
> > This isn't bad, but in my opinion the << syntax is better despite my
> > strong dislike for operator overloading.
> 
> Maybe a more or less obvious choice will do
> 
>     throw my_error() = error_info<tag>(whatever),
>         error_info<another_tag>(something_else) // ...

Why not use approach similar (if not based upon) named function parameters:

throw my_error().data(( tag_errno = errno, tag_name = name, .... ))

or for exception classes with trivial forwarding temaplte constructor

throw my_error(( tag_errno = errno, tag_name = name, .... ))

I also strongly in favor boost::optional instead of pointer result type.

Gennadiy