[boost] [extension] Problem with reference types

From: Robert Dailey (rcdailey_at_[hidden])
Date: 2008-07-09 18:34:28

I have the following exported factory function in a DLL I'm building on
Windows:

extern "C" void BOOST_EXTENSION_EXPORT_DECL
export_aspects( boost::extensions::factory_map& fm )
{
    using namespace vfx::aspects;
    using namespace vfx::messenger;

    fm.get<Aspect, MessageReader&, unsigned int>()[0].set<Appearance>();
    fm.get<Aspect, MessageReader&, unsigned int>()[1].set<Health>();
}

As you can see, I am specifying that each class accepts a single
construction parameter- a reference to a MessageReader object. However, this
isn't compiling because I don't think that it likes reference types. How can
I specify that the constructor takes a reference? boost::ref? I would post
the compiler warnings & errors I'm getting, however they're exceedingly
large. Most of the warnings and errors are coming from std::map, basically
complaining that it's trying to create a map of reference types, which can't
possibly work. Help is appreciated.

As an unrelated note, I would really like to see the template parameters
cleaned up. There's at least 5 places I've had to redundantly specify the
same 3 template parameters (like in the example above). I already brought
this up in another thread, but I can't tell you how important it is. If I
ever change the number of construction parameters my Appearance or Health
classes take (mapped above), I will have to shift through 5 or more files
simply to adjust all of the template parameters to make everything compile.