// testing polylists.dll routines
using System;

public class polyuse
{
  public static void Main()
  {
     cell<integer> I = new cell<integer>(new integer(2),
         new cell<integer>(new integer(5),null));
     cell<rational> R = new cell<rational>(new rational(1,2), 
         new cell<rational>(new rational(1,4),null));

     Console.WriteLine(I.length());
     Console.WriteLine(I.sum());
     Console.WriteLine(R.sum());

     cell<str> S = new cell<str>(new str("hello"),
         new cell<str>(new str(" world"),null));
     Console.WriteLine(S.sum());
  }  // Main
}

// compile with csc polyuse.cs /r:polylists.dll


//// Important: I can extend the definition without creating inconsistencies

// add new class for strings

public class str : addable<str>
{
   string s;
   public str(string a) {s=a;}
   public str add(str B) { return new str(s+B.s); }
   public override string ToString() { return s; }   
}