我有一个ParseTree监听器实现,我用来在标准VBA模块中获取全局范围声明:
public class DeclarationSectionListener : DeclarationListener { private bool _insideProcedure; public override void EnterVariableStmt(VisualBasic6Parser.VariableStmtContext context) { var visibility = context.visibility(); if (!_insideProcedure && visibility == null || visibility.GetText() == Tokens.Public || visibility.GetText() == Tokens.Global) { base.EnterVariableStmt(context); } } public override void EnterConstStmt(VisualBasic6Parser.ConstStmtContext context) { var visibility = context.visibility(); if (!_insideProcedure && visibility == null || visibility.GetText() == Tokens.Public || visibility.GetText() == Tokens.Global) { base.EnterConstStmt(context); } } public override void EnterArg(VisualBasic6Parser.ArgContext context) { return; } public override void EnterSubStmt(VisualBasic6Parser.SubStmtContext context) { _insideProcedure = true; } public override void EnterFunctionStmt(VisualBasic6Parser.FunctionStmtContext context) { _insideProcedure = true; } public override void EnterPropertyGetStmt(VisualBasic6Parser.PropertyGetStmtContext context) { _insideProcedure = true; } public override void EnterPropertyLetStmt(VisualBasic6Parser.PropertyLetStmtContext context) { _insideProcedure = true; } public override void ExitPropertySetStmt(VisualBasic6Parser.PropertySetStmtContext context) { _insideProcedure = true; } }
有没有办法告诉树步行者停止走路?说我有一个这样的VBA模块:
Public Const foo = 123 Public bar As String Public Sub DoSomething() ' some code End Sub ' ... ' 10K more lines of code ' ... Private Function GetSomething() As String ' some code End Function
一旦进入Public Sub DoSomething(),我希望树木随便停止走解析树,因为我对下面的任何东西都不感兴趣.目前,我正在走整个解析树,只是在任何程序范围内,我都不用做任何事情.
有没有办法,从解析树监听器实现中,告诉步行者停止走树?
解决方法
是的,您可以执行以下操作之一:
>抛出异常,如CancellationException
>创建一个扩展ParseTreeWalker的新课程,并提供您自己的实现walk
,了解您需要的取消概念.从current implementation of walk
开始,修改它以满足您的需求是有意义的.