text: public override ICollection<IParseTree> Evaluate(IParseTree t){IList<IParseTree> nodes = new List<IParseTree>();foreach (ITree c in Trees.GetChildren(t)){if (c is ParserRuleContext){ParserRuleContext ctx = (ParserRuleContext)c;if ((ctx.RuleIndex == ruleIndex && !invert) || (ctx.RuleIndex != ruleIndex && invert)){nodes.Add(ctx);}}}return nodes;}