function.hpp: some ideas

From: Geurt Vos (G.Vos_at_[hidden])
Date: 2001-05-03 02:26:24

Idea 1:
Support for 0 (and only 0) assignment could still be
considered, it does however require a change in the 
interface. Here's the idea: 'function' defines an empty
class in its private section, and adds an assignment 
operator which takes a pointer to this class. Now the
user can _only_ assign 0 to it. Here's an example:

class function {
    class assign0 { };
public:
    function& operator=(const assign0 *)
    {
        clear();
        return *this;
    }
};

Problems arise when there's an assignment operator
which has a parameter that could also be of type
'int', because then 0 assignment will use that 
operator. In function's case, this means that the
assignment operator template has got to go:

    template<typename Functor>						
    function& operator=([const] Functor [&]f)

Idea 2:
function is there to take either a function or a
functor, while bind can be used to turn a member
function into a functor. I was just wondering, 
wouldn't it be easier (and maybe even more 
consistent) if 'bind' could take either a function
or a member function, and 'function' only functors?

Geurt