On 7/3/06, Emil Dotchevski <emildotchevski@hotmail.com> wrote:
I am not quite sure how to inerpret this... Is it "go ahead, we'll discuss the details during the formal review process"? Or is it complete lack of interest for adding such a library to Boost?
I just read through a good part of the documentation, and I see good potential uses for this library. I have a couple of concerns though, please see below...
Anyway... Here is the link to the documentation again:
http://www.revergestudios.com/exception/exception.htm
If you click "download", you'll get the source code, as well as an example and a test suite, complete with Boost Build jamfiles.
I haven't downloaded the files yet, but am planning to test them out soon. I have a few questions though, which you might be able to address: 1) use of dynamic_cast in the following snippet: catch( read_error & x ) { if( exception_info * xi = dynamic_cast<exception_info *>(&x) ) if( exception_errno * err = get_errno(*xi) ) ....; //err->code() is the captured errno. //err->strerror() is the corresponding error string. } Perhaps this will be a major barrier to adoption, since it reads more like a kludge than a way of exposing a well-thought about interface. This also seems like too much work for exception handling -- which seems harder to do than just creating my own exception class which derives from std::exception, and then a custom constructor that contains a copy of the information object that I know I want to be available from those that will be receiving the exception. Is there a good reason why you're not using a "composite-style" [see GoF composite pattern] exception if you intend to be able to add information as the exception is propagated through the try {} catch(...) {} blocks? 2) Have you considered using Boost.Fusion to create mappings of compile-time types to runtime values so that you can access the information objects in a type-safe manner? I'm not an expert about it, but it might be easier to do something like: catch (exception_info & x) { my_type temp = at_key<my_type>(x.objects); }; Wherein `x.objects` is a Boost.Fusion map, and allows you to map values to types? Perhaps you can come up with another way of avoiding the use of dynamic_cast<>() but with what you're trying to achieve, I think Boost.Fusion will definitely be able to help you out with the interface part. I think I have more questions, but I will reserve them when either the library gets scheduled for formal review, or when I actually get the time to test out the available implementation. But generally, on my part I am interested in this library. -- Dean Michael C. Berris C/C++ Software Architect Orange and Bronze Software Labs http://3w-agility.blogspot.com/ http://cplusplus-soup.blogspot.com/ Mobile: +639287291459 Email: dean [at] orangeandbronze [dot] com