Inheritance: BooleanExpression
 public void Visit(LessThanExpression expression, CommonTree tree)
 {
     SetLine(expression, tree);
     Parent(tree).Children.Add(expression);
     VisitChildren(tree);
 }
 public void Visit(LessThanExpression expression)
 {
     DoBoolean(expression, CodeBinaryOperatorType.LessThan);
 }