functor

function.h

template <typename Sig>
class Function;

template <typename R, typename... Args>
class Function<R(Args...)> {
public:
    typedef R(*Runtype)(Args...);
    Function(Runtype f) : f_(f) {}

    R operator()(Args... args) {
        return (*f_)(args...);
    }

private:
    Runtype f_;
};

template <typename R, typename T, typename... Args>
class Function<R(T::*)(Args...)> {
public:
    // typedef R(*RunType)(T*, Args...);
    Function(T* object, R(T::*method)(Args...))
        : object_(object), method_(method) {}

    R operator()(Args... args) {
        return (object_->*method_)(args...);
    }

private:
    T* object_;
    R (T::*method_)(Args...);
};

void func() {}
int func3(int) { return 1; }

struct Foo {
    void bar(int v) { std::cout << "Foo::bar(" << v << ")" << std::endl; }
};


void test_function() {
    Function<void()> f1(&func);
    f1();

    Function<int(int)> f3(&func3);
    f3(1);

    Foo foo;
    Function<void(Foo::*)(int)> f4(&foo, &Foo::bar);
    f4(1);
};