public void Visit(Not not)
 {
     _sb.Append("~");
     not.Operand.Accept(this);
 }
 public void Visit(Not not)
 {
     not.Operand.Accept(this);
     MustBeSboolOrSubtype(not.Operand.SmclType, string.Format("The operand in the expression\n ({0} must be bool", not));
     not.SmclType = BoolType;
 }