[fU] a more generic, in-language solution for "the class name problem"

[stephan b. <st...@wa...>]

This should work for just about any project. i'll admit it bloats the glo=
bal=20
space a bit (one extra helper class per registered class), but it's very=20
generic and easy to use...


namespace { // anon ns important for linking
        /**
           A slimmer, more general-purposes class than
           classloader_registerer<>.
           It MUST be specialized to work.
        */
        template <class T> struct class_name
        {=20
                class_name(){}
                ~class_name(){}
                operator const char * () const
                {=20
                        assert( 0 /* this class_name<> is unspecialized! =
*/ );
                        return "error::class_name<unspecialized>";
// a more sane default would be typeid(T).name()
                }
                // static const char * classname =3D 0;
                // ^^^^^ we can't initalized a non-integral type this way=
 :(
                static const char * name()
                {
                        assert( 0 /* this class_name<> is unspecialized! =
*/ );
                        return "error::class_name<unspecialized>";
                }
        };
}

// call this from outside a namespace to register a class_name<Type>
#define CLASS_NAME(Type) \
=09namespace {\
        template <> struct class_name<Type> {\
                class_name(){}; ~class_name(){}; \
=09        static const char * name() {return # Type; }\
                operator const char * () const { return this->name(); }\
        };}



Usage:

CLASS_NAME(MyClass);

COUT << "name =3D " << class_name<MyClass>() << std::endl;
COUT << "name =3D " << class_name<MyClass>::name() << std::endl;


Caveat:

typedef std::vector<int> FooType;
CLASS_NAME(FooType); // will use "FooType" :(

Maybe that's useful in some contexts, but i'm not sure if it's a feature =
or a=20
bug. It's not name-collision-proof, but it is the type passed to=20
class_name<T> which is important, anyway.


This would be more efficient to implement as global funcs, but func templ=
ates=20
can't be specialized, AFAIR.

--=20
----- st...@wa...
http://qub.sourceforge.net  http://libfunutil.sourceforge.net        =20
http://toc.sourceforge.net  http://countermoves.sourceforge.net
http://stephan.rootonfire.org  et al.