appender

#include <vector>
#include <string>
#include <cstdio>
#include <functional>

typedef std::function<void(std::string)> Func;
class Menu
{
public:
  struct Entry
  {
    std::string cmd;
    Func func;
  };
  const class AppendHelper
  {
  public:
    AppendHelper(Menu &menu) : menu(menu) {}
    const AppendHelper &operator()(std::string cmd, Func func) const
    { menu._command_set.push_back({cmd, func}); return *this; }
  private:
    Menu &menu;
  } append_menu = {*this};

  // For debugging
  void list_commands()
  {
    for(Entry e : _command_set) {
      printf("%s\t: %X\n", e.cmd.c_str(), &e.func);
    }
  }

private:
  std::vector<Entry> _command_set;
};

int main()
{
  Menu menu;
  menu.append_menu
    ("hehe", [] (std::string input) {printf("hehe");})
    ("haha", [] (std::string input) {printf("haha");});

  menu.list_commands();
}