#include <iostream>
#include <string>
#include <unordered_map>
#include <functional>

class Conn;
typedef void (Conn::*ProcFn)();

class Conn
{
  private:
  void proc_ping();

  static const std::unordered_map<std::string, ProcFn> handlers;

  public:
  void simulate();
};

const std::unordered_map<std::string, ProcFn> Conn::handlers = {
  std::pair("ping", &Conn::proc_ping)
};

void Conn::proc_ping()
{
  std::cout << "ping!" << std::endl;
}

void Conn::simulate()
{
  auto pfn = handlers.at("ping");

  std::invoke(pfn, this);
}

int main()
{
  Conn c;

  c.simulate();
}

#include <iostream>
#include <string>
#include <unordered_map>
#include <functional>

class ConnBase;
typedef void (ConnBase::*ProcFn)();

class ConnBase
{
  protected:
  void proc_ping();
};

void ConnBase::proc_ping()
{
  std::cout << "ping!" << std::endl;
}

class ConnMgmt : public ConnBase
{
  protected:
  static const std::unordered_map<std::string, ProcFn> handlers;

  void proc_create_user();

  public:
  void simulate();
};

void ConnMgmt::proc_create_user()
{
  std::cout << "create user!" << std::endl;
}

const std::unordered_map<std::string, ProcFn> ConnMgmt::handlers = {
  std::pair("ping", &ConnBase::proc_ping),
  std::pair("create_user", &ConnMgmt::proc_create_user)
};

void ConnMgmt::simulate()
{
  auto pfn = handlers.at("ping");

  std::invoke(pfn, this);

  pfn = handlers.at("create_user");

  std::invoke(pfn, this);
}

int main()
{
  ConnMgmt c;

  c.simulate();
}