On 08/03/12 07:58, Sohail Somani wrote:
On 03/08/2012 3:17 AM, Jan Herrmann wrote:
Additionally it can be used as a base for multimethod implementation.
This is much more interesting to me. Can you elaborate or give some sample code?
Then you might be interested in the multimethods discussion in a July 2010 thread:
http://thread.gmane.org/gmane.comp.lib.boost.devel/206203 Thank you for this link.
As shown elsewhere in that thread, there's multimethod code available already in the boost sandbox. That code:
http://svn.boost.org/svn/boost/sandbox/variadic_templates/libs/composite_sto...
is one example. Another, more complete example, is here:
http://svn.boost.org/svn/boost/sandbox/variadic_templates/libs/composite_sto... Thank you for these links, too.
The more complete example shows the method can be used both with virtual functions and discriminated unions, such as boost:: variant or that in:
http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/composite_st...
Unfortunately, the multimethod using the one_of_maybe discriminated union can be a compile-time hog (based on some simple tests I've run). I've no idea why :( I have included visiting variants, too. It was really simple. I furthermore can visiting anys and polymorphic base classes with a wrapper. It uses any_cast or dynamic cast and works like Alexandrescus static dispatcher. The only problem I have and which i cant solve is the
On 03.08.2012 15:24, Larry Evans wrote: polynomial amount of code. The compiler has simply to build a lot of classes and virtual functions for every case.
HTH.
-Larry
My main idea is to provide (normally) 2 templated functions for all visitable types: template<class static_visitor> void accept(MyClass const&, static_visitor& sv); template<class static_visitor> void accept(MyClass & static_visitor& sv); As long as these functions can be found you can build a const correct multimethod implementation on top of them without knowing anything about MyClass. Please look at https://raw.github.com/janherrmann/visitor/master/dispatch.hpp . Best regards Jan Herrmann