short-adl-demo.cpp

#include <iostream>
#include <cstring>
#include <cstddef>
#include <string>

namespace impl {

template <typename Type>
auto swap(Type& first, Type& second) -> void {
    std::cout << "No swap :(";
    auto temp = std::move(first);
    first = std::move(second);
    second = std::move(temp);
}

} // namespace impl

namespace my_own_std {

template <typename Type>
auto swap(Type& first, Type& second) -> void {
    using impl::swap;
    swap(first, second);
}

} // namespace my_own_std

namespace own {
    class IHaveMyOwn  {};
    class IDontHaveMyOwn  {};


    auto swap(IHaveMyOwn&, IHaveMyOwn&) -> void { std::cout << "I have my own!\n"; }
} // namespace own

auto main() -> int {
    auto i_have_my_own = own::IHaveMyOwn();
    auto i_have_my_own2 = own::IHaveMyOwn();
    my_own_std::swap(i_have_my_own, i_have_my_own2);

    auto i_dont_have_my_own = own::IDontHaveMyOwn();
    auto i_dont_have_my_own2 = own::IDontHaveMyOwn();

    my_own_std::swap(i_dont_have_my_own, i_dont_have_my_own2);
}