operator-keyword

I want to write a pointer in c++ (or in c++0x), that will points to a operator of a class lets say A or B. Is there any method to do it? Of course there is a syntax like int (A::*_p) (); but it doesn't solve this problem. I want to make general pointer, not specifying the base class for it - only pointer for "operator function" #include <thread> #include <iostream> using namespace std; class A { public: int operator()() { return 10; } }; class B { public: int operator()() { return 11; } }; int main() { A a; int (*_p) (); _p = a.operator(); cout << _p(); B b; _p = b.operator(); cout << _p(); }

What do I need to change to make this work? class A: @staticmethod def __getitem__(val): return "It works" print A[0] Note that I am calling the __getitem__ method on the type A . When an object is indexed, the special method __getitem__ is looked for first in the object's class. A class itself is an object, and the class of a class is usually type . So to override __getitem__ for a class, you can redefine its metaclass (to make it a subclass of type ): class MetaA(type): def __getitem__(cls,val): return "It works" class A(object): __metaclass__=MetaA pass print(A[0]) # It works In Python3 the

I'm trying to be lazy and implement the cast operators in the abstract base class rather than in each of the derived concrete classes. I've managed to cast one way, but I'm unable to cast the other. I think it might not be possible, but wanted to pick the collective SO mind before giving up: public interface IValueType<T> { T Value{ get; set; } } public abstract class ValueType<T> : IValueType<T> { public abstract T Value { get; set; } public static explicit operator T(ValueType<T> vt) { if(vt == null) return default(T); return vt.Value; } public static implicit operator ValueType<T>(T val) {

The exact situation is next: I have defined in system API structs CGPoint and CGSize , and I want to be able to write my_point = my_size . I can't modify CGPoint struct, only can write external operator. I can write binary operators ( + , - , ...) but operator= must by declared inside struct. So is there any other solution? To make the expression a = b; compile you need to either have an operator= in the type of a that takes an element of the type of b , or a type implicitly convertible from b . The first case is ruled out, since operator= must be a member of the class, and since you cannot