On 12/03/12 11:40, Larry Evans wrote:
On 12/03/12 08:13, Per Karlström wrote: [snip]
I have been tinkering on a template library to ease the use of double dispatching. Now I know there are other techniques such as visitor patterns that might solve this problem in a more general way. However I believe that there are occasions when using double dispatch is a good way forward. I have some excerpts of example code at the end of this mail.
Of course if I somehow have missed a boost library that already handles this I would be happy to know about it. [snip]
There's multiple dispatch code here:
http://svn.boost.org/svn/boost/sandbox/variadic_templates/libs/composite_sto...
The predator_prey.cpp uses virtual functions for dispatching. The one_of_multiple_dispatch.test.cpp uses either virtual functions or switches to do the dispatching.
Unfortunately, I found the timing was pretty slow on the one_of_multiple_dispatch vs. the variant visitor :(
I meant the compile times were slow. I didn't bother with runtimes. Also, I provided a switch implementation because others (in this NG, IIRC) have said that was faster than virtual functions for dispatching. Anyway, the timing results are attached for a clang compiler. The table shows the ratio of the times w.r.t. an implementation called CLOPTR, which was posted in the earlier post on boost.user: From: Paul <peebor@gmail.com> Newsgroups: gmane.comp.lib.boost.user Subject: Re: large variant performance compared (50 elements) Date: Thu, 27 Jan 2011 20:19:08 +0100 -regards, Larry