binding a c++ unary_function to lua

["Panagiotis Vossos" <pavossos@...>]

While experimenting with stl binders yesterday, I had the following
problem.  Let's say we have a
derived from std::unary_function c++ struct with the method:
int operator()(lua_State *L) const { ... }.

Is there any easy way to make it available to lua as a normal function?

thanks in advance,
panagiotis.