tupleof for inherited classes.

[mrdarksys]

[Problem]
How can I use enumFields() function of Engine class for enumerate 
all fields of inherited classes?
I want to do without templates if possibly.

Code [example]:
//============
import std.stdio;

class Engine
   {
     public:
       int publicField;

       void enumFields()
         {
           writeln("Engine prints:");
           foreach(ref field; this.tupleof)
             writeln(field);
         }

     private:
       bool privateField;

     protected:
       string protectedField = "s";
   }

class Some : Engine
   {
     public:
       int oneMoreField = 11;

       void enumFields2()
         {
           writeln("Some prints:");
           foreach(field; this.tupleof)
             writeln(field);
         }

     protected:
       string protectedField = "o";
   }

int main()
   {
     auto objE = new Engine();
     auto objS = new Some();

     objE.enumFields();

     objS.publicField = 4;

     objS.enumFields();

     objS.enumFields2();

     return 0;
   }
//==============

[Actual] output is:
//==============
Engine prints:
0
false
s
Engine prints:
4
false
s
Some prints:
11
o
//==============

[Expected] output is:
//==============
Engine prints:
0
false
s
Engine prints:
4
false
o
11
Some prints:
4
false
o
11
//==============