[boost] 'function' idea

From: Aleksey Gurtovoy (agurtovoy_at_[hidden])
Date: 2002-11-09 04:10:24

A crazy thought - how about enabling something like this:

    #include <boost/function.hpp>
    #include <cassert>

    int main()
    {
        boost::function<bool ()> f0 = true;
        boost::function<int ()> f1 = -1;
        boost::function<std::string ()> f2= "text";

        assert(f0() == true);
        assert(f1() == -1);
        assert(f2() == "text");
    }

In other words, can we allow a zero-arity 'function<...>' to treat ordinary
values as first-class function objects? 

It would make a lot of things so cooler :). For instance:

    class widget
    {
    public:
        // ...
        typedef boost::function<bool ()> bool_arg_t;
        
        self_t&     enable(bool_arg_t a_enable); // note the signature!
        bool        is_enabled() const;
    };

    int main()
    {
        widget w;
        w.enable(true); // ordinary syntax/semantics
        assert(w.is_enabled())
        
        widget w2;
        w.enable(boost::bind(&widget::is_enabled, &w2)); // here!
        w2.enable(false);
        assert(!w.is_enabled()) // !
    }

Pure & beautiful, IMO.

Aleksey