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#include <iostream>
#include <vector>
#include <boost/openmethod.hpp>
#include <boost/openmethod/initialize.hpp>
struct Animal {
const char* name;
Animal(const char* name) : name(name) {
}
};
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(
meet, (virtual_ptr<Animal>, virtual_ptr<Animal>, std::ostream&), void);
BOOST_OPENMETHOD_OVERRIDE(
meet, (virtual_ptr<Cat> a1, virtual_ptr<Cat> a2, std::ostream& os), void) {
os << a1->name << " ignores " << a2->name << "\n";
}
BOOST_OPENMETHOD_OVERRIDE(
meet, (virtual_ptr<Dog> a1, virtual_ptr<Cat> a2, std::ostream& os), void) {
os << a1->name << " chases " << a2->name << "\n";
}
BOOST_OPENMETHOD_OVERRIDE(
meet, (virtual_ptr<Cat> a1, virtual_ptr<Dog> a2, std::ostream& os), void) {
os << a1->name << " runs away from " << a2->name << "\n";
}
BOOST_OPENMETHOD_OVERRIDE(
meet, (virtual_ptr<Dog> a1, virtual_ptr<Dog> a2, std::ostream& os), void) {
os << a1->name << " wags tail at " << a2->name << "\n";
}
void meet_animals(
const std::vector<virtual_ptr<Animal>>& animals, std::ostream& os) {
for (auto animal : animals) {
for (auto other : animals) {
if (&animal != &other) {
meet(animal, other, os);
}
}
}
}
auto main() -> int {
boost::openmethod::initialize();
Dog hector{"Hector"}, snoopy{"Snoopy"};
Cat felix{"Felix"}, sylvester{"Sylvester"};
std::vector<virtual_ptr<Animal>> animals = {
virtual_ptr<Dog>::final(hector), virtual_ptr<Cat>::final(felix),
virtual_ptr<Cat>::final(sylvester), virtual_ptr<Dog>::final(snoopy)};
meet_animals(animals, std::cout);
}
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