C++Talk.NET

Florian Preknya · Guest

I read about dynamic_any a year ago, once with the the dynamic_any
campaign proposed by CUJ (see
[url]http://www.cuj.com/documents/s=8470/cujweb0309nasonov)[/url]. I did not see
the power of the construction that time, but nowadays I realized I need
something like dynamic_any for my current project. I don't know if it's
feasible, but my ideea was to use dynamic_any instead of template
parameters for methods that I want to keep virtual, but also permit
"generic" parameters.
So, what's the status of dynamic_any in the boost corner? It's in
proposal form, or it was removed (because it is covered by other
libraries), etc. ? I saw that the dynamic_any project is on hold, I
think was never compiled on Windows systems. Also, it generates an
INTERNAL_COMPILER_ERROR on VC7.1. (I can give further details if
needed). Also, the dynamic_any version I take from sourceforge rely on
an older version of boost and I had to modify some include paths.

Or, is another trick for my problem that can be done without
dynamic_any? (see a simplified sample)

// what I want, but not possible
// Note that I don't want to make the Factory class a template class!!
class AKindOfFactory
{
template <class Iterator>
virtual boost::shared_ptr<NewObject> create(Iterator start,
Iterator end) = 0;
};

// can be redesigned with dynamic_any like this

typedef dynamic_any::any<mpl::list dynamic_any::increment> > any_iterator;

class AKindOfFactory
{
virtual boost::shared_ptr<NewObject> create(any_iterator start,
any_iterator end) = 0;
};

Thanks,
Florian Preknya

[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]

Alexander Nasonov · Guest

Hello Florian,
This library is still under (not active, though) development. I'm not
quite satisfied with operation's interface especially with
multiple-dispatch. Good news is that I'm slowly moving in this
direction. In order to get multiple-dispatch working as I like, I
invented "overloads" library. It's now in MPL todo list:
http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?MPL_TODO_List

I've already applied the overloads library to finite state machines and
I'm going to apply it to dynamic_any soon. I can't tell you when it
will be done because it's a lot of work and I never have enough time.

Regarding your problem, it's worth looking at another library under
construction, namely, any_iterator:
http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?LibrariesUnderConstruction
--
Alexander Nasonov

[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]