How to list available functions? about interpreter HOT 1 CLOSED

int main(int argc, char* argv[])
{  
  Interpreter ir;

  ir.addFunction("summ", [](const vector<string>& args) ->string {
    int res = 0;
    for (auto& v : args) {
      if (isNumber(v)) res += stoi(v);
    }
    return to_string(res);
  });

  ir.addFunction("switch", [](const vector<string>& args) ->string {
    
    if (!args.empty()) {
      string key = args[0];
      for (size_t i = 1; i < args.size(); ++i) {
        if (key == args[i]) {
          return "1";
        }
      }
    }
    return "0";
  });


  ir.addFunction("print", [](const vector<string>& args) ->string {
    for (auto& v : args) {
      printf("%s\n", v.c_str());
    }
    return "";
  });

  ir.addFunction("help", [&ir](const vector<string>& args) -> string
    {
      std::string result = "Available Functions: ";
      for (auto& a : ir.allEntities()) {
        if (a.type == Interpreter::EntityType::FUNCTION) {
          result += a.name + ",";
        }
      }
      result.pop_back();

      return  result;
    });

  string scenar = "$a; $b; summ($b, $a); switch($a, 5); help();";
  string res = ir.cmd(scenar); // summ,switch,help
 
  return 0; 
}