Re: [boost] Any interest in trap_exceptions functionality?

Subject: Re: [boost] Any interest in trap_exceptions functionality?
From: Andy Venikov (avenikov_at_[hidden])
Date: 2010-08-02 12:36:12

David Abrahams wrote:
> At Fri, 30 Jul 2010 16:21:13 -0400,
> Andy Venikov wrote:
>>    I recently took a crack at this task and came up with a generic way 
>> to trap exception.
>>
>> Here's a brief API:
>>
>> trap_exceptions(<list-of-exception-handlers>);
> 
> I think there's something like this in Boost.Python, and, IIUC, in
> Boost.Test as well.  Ah, yes.  I suggest you review this thread:
> http://www.mail-archive.com/[e-mail]/msg05179.html

Thanks for the link, it shows that there's an interest in something like 
that.

If I understand that thread correctly, boost.Python provides a way to 
dynamically register exception translators (which for all intents and 
purposes are just handlers)for different types of exceptions.

While I think that it's somewhat similar to trap_exceptions, the 
purposes are very different. Boost.Python.exception_transator is totally 
dynamic, hence the need to use virtual functions and "new". You also 
have to use the "register" mechanism to register all your handlers 
individually. I understand that this approach is a must where you may 
have dynamic components like in Boost.Python and Boos.Test, but when you 
are simply trying to re-factor your code so that the resulting binary is 
the same, but the source is organized better, I think a static approach 
is more fitting. If I didn't have a requirement to support function 
pointers, then the result of trap_exceptions could've been just a type:

trap_exceptions<...list of exception handling functor types...>::type

Even with function pointers, their type and their number is known and 
queriable (they are stored in a tuple<>). The only indirection here is 
the function call itself. When functors are used, there's no indirection 
whatsoever.

Thanks,
     Andy.