public void Visit(Display print)
 {
     _sb.Append("display(");
     print.Exp.Accept(this);
     _sb.Append(")");
 }
 public void Visit(Display print)
 {
     print.Exp.Accept(this);
     /*
     if (!print.Exp.SmclType.Equals(StringType))
     {
         throw new TypeCheckingException("You can only print strings, not " + print.Exp.SmclType);
     }
      */
 }