openmethod/ce/uni-method-vptr.cpp

#include <iostream>
#include <vector>
#include <boost/openmethod.hpp>
#include <boost/openmethod/initialize.hpp>

struct Animal {
    const char* name;
    Animal(const char* name) : name(name) {
    }
    virtual ~Animal() {
    }
};

struct Dog : Animal {
    using Animal::Animal;
};

struct Cat : Animal {
    using Animal::Animal;
};

BOOST_OPENMETHOD_CLASSES(Animal, Dog, Cat);

using boost::openmethod::virtual_ptr;

BOOST_OPENMETHOD(poke, (virtual_ptr<Animal>, std::ostream&), void);

BOOST_OPENMETHOD_OVERRIDE(
    poke, (virtual_ptr<Cat> animal, std::ostream& os), void) {
    os << animal->name << " hisses.\n";
}

BOOST_OPENMETHOD_OVERRIDE(
    poke, (virtual_ptr<Dog> animal, std::ostream& os), void) {
    os << animal->name << " barks.\n";
}

void poke_animals(
    const std::vector<virtual_ptr<Animal>>& animals, std::ostream& os) {
    for (auto animal : animals) {
        poke(animal, os);
    }
}

auto main() -> int {
    boost::openmethod::initialize();

    Dog hector{"Hector"}, snoopy{"Snoopy"};
    Cat felix{"Felix"}, sylvester{"Sylvester"};
    std::vector<virtual_ptr<Animal>> animals = {
        hector, felix, sylvester, snoopy};

    poke_animals(animals, std::cout);
}