[boost] [review] Exception - result

From: Tobias Schwinger (tschwinger_at_[hidden])
Date: 2007-11-07 05:10:34

I'm pleased to announce that the Exception library has been accepted 
into boost. Thanks to all formal and informal reviewers and to Emil 
Dotchevski for the library!

Summary of possible improvements:
=================================

Design
------

Nearly all reviewers made suggestions for syntactic improvements. The 
"tag(value) syntax" (as suggested by John Torjo) for instance provides 
sufficient syntactic sugar and seems lightweight to implement.

Suggested features in this area are (those are implementable on top of 
the current design - but will keep users from reinventing the wheel if 
provided by the library):
- Support for grouping information, and
- support for generating stack traces.

I personally still have a bad feeling about 'enable_error_info' - let's 
just revisit and discuss it on the list before changing 
boost::throw_exception.

The related discussions about clone/rethrow support is still ongoing.

Documentation
-------------

Best practices for the catch-site should be clarified in the documentation.

Same goes for using the same tag multiple types with one exception object.

Other comments should be addressed (I won't put much energy into 
summarizing documentation comments, guessing most of them might have 
been taken care of, already).

Deployment
----------

There was a suggestion (from Pavel Vozenilek) to put #ifdef around the 
code of boost::exception that could be put into a separate translation 
unit. There should probably also be a 'build' directory and a Jamfile so 
there is smooth integration with the Boost build system.

Of course, Jamfiles for test/examples should be added.

Implementation
--------------

Several reviewers noted that the library is rather allocation-heavy. It 
pretty much comes down to shared_ptr overuse (causing many unnecessary 
allocations of small objects and synchronized instructions to be 
executed) though not in performance critical code possibly affecting 
other threads and future allocations.

--
Tobias Schwinger
- Review Manager -