Метапрограммирование Javascript

Есть ли способ указать в javascript нечто подобное следующему?

var c = {};
c.a = function() { }

c.__call__ = function (function_name, args) {
    c[function_name] = function () { }; //it doesn't have to capture c... we can also have the obj passed in
    return c[function_name](args);
}

c.a(); //calls c.a() directly
c.b(); //goes into c.__call__ because c.b() doesn't exist