public override SelectionRuleNode VisitNotExpression(TmtParser.NotExpressionContext context) { SelectionRuleNode result = null; var not = new NotRuleNode() { Name = "NOT" }; if (Rule == null) { Rule = not; } var expression = Visit(context.expression()); if (expression != null) { not.Child = expression; result = not; } else { Rule = null; } return(result); }