Implementing multi-methods for C++ in GCC

[Joe Buck]

On Wed, Sep 29, 2004 at 09:58:48AM +0200, Lassi A.Tuura wrote:
> A few years ago I implemented multi-methods as a C++ library and it has 
> served us pretty well...
> 
> However the implementation also proves that it's very ugly to do 
> without compiler support.  So I would now like to pursue a proposal for 
> the standards committee.  I think I could make my case a bit stronger 
> if there also was an (experimental) implementation in some compiler.
> ...
> I'll work in parallel on a proposal to the standards committee.

I strongly suggest that you have at least a draft standard before you
start, and that you think seriously about corner cases and interaction
with other language features before you start coding (and let others try
to find flaws with it as well).  The fact that this hasn't always been
done has contributed to lots of problems with GCC extensions in the past,
and the implementation will be cleaner if you identify as many issues
as possible up front.