public void Visit(Put put)
 {
     _sb.Append(".put(");
     put.Exp.Accept(this);
     _sb.Append(")");
 }
 // Values may be placed in the tunnel using
 public void Visit(Put put)
 {
     put.Exp.Accept(this);
     put.SmclType = put.Exp.SmclType;
 }