Re: Review: Boost Test Library

From: williamkempf_at_[hidden]
Date: 2001-02-13 16:57:23

Just a thought to spark others creativity...

I've been thinking a bit about the desire for catch_exceptions() to 
be able to handle "registered" exception types (during my breaks from
documenting the BTL, which should be done in a day or two for those 
who are helping me finalize this before submitting), and a trick 
suggested on a programming site I read in the past came to mind 
(sorry, I can't give exact credit here).  Error handling functions 
can be registered and called from catch blocks by using the following 
idiom:

bool handle_my_error_types()
{
   try
   {
      throw; // re-throw the last exception
   }
   catch (my_specific_error_type err)
   {
      // handle the error
      return true; // we handled the error
   }
   catch (...)
   {
      return false; // we didn't handle the error
   }
}

void example()
{
   try
   {
      // some code that throws
   }
   catch (...)
   {
      if (handle_my_error_types())
         cout << "handled" << endl;
      else
         cout << "unknown exception type" << endl;
   }
}

I think that this idiom could be used to allow test programs 
to "push" handlers for specific exception types that they used onto 
a "handler stack" that would be used by catch_exceptions().  This 
should allow for very specific reports about what exceptions are 
caught by the test framework, even though the framework is not aware 
of library defined exception types.

The one caveat is that (at the time I found this idiom at least) VC++ 
couldn't handle this (it tries to destruct the exceptions multiple 
times!).

Any thoughts or comments on the idea?

Bill Kempf