Tiny std::function implementation

function.cpp

/* EDIT:
 * For future reference, this code doesn't work right so don't use it.
 * (but probably could be fixed with some care and attention)
 */

// Tiny std::function workalike, to allow storing lambdas with captures. (public domain)
template <typename> struct fnptr;
template <typename Ret, typename... Args> struct fnptr<Ret(Args...)> {
	void *obj = nullptr;
	Ret (*wrap)(void*, Args...) = nullptr;

	fnptr() = default;
	fnptr(Ret target(Args...)) : fnptr([=] (Args... args) { return target(args...); }) {}
	template <typename T> fnptr(T&& fn) : obj(&fn), wrap([](void *fn, Args... args) { return (*(T *)fn)(args...); }) {}

	Ret operator()(Args... args) const { return wrap(obj, args...); }
};

// Example:
//
// void hello() { printf("hello\n"); }
//
// fnptr<void()> x;
//
// int main() {
//    int q=1;
//    x = hello;
//    x();
//    x = [&q] { q++; printf("again\n"); };
//    x();
// }