如何在不改变语法的情况下知道访问期间ANTLR解析器当前处于哪个替代规则
我查看了这些，它们似乎没有解决问题：
例如：
oC_ListOperatorExpression :
( SP IN SP? oC_PropertyOrLabelsExpression )
| ( SP? '[' oC_Expression ']' )
| ( SP? '[' oC_Expression? '..' oC_Expression? ']' ) ;
在这种特殊情况下，替代方案 2 和替代方案 3 没有特殊标记或位于固定位置的标记，我可以利用它们来区分它们。
在不改变语法的情况下，如何判断我在下面使用哪种替代方案？
antlrcpp::Any visitOC_ListOperatorExpression(
CypherParser::OC_ListOperatorExpressionContext* ctx) override {
}
我正在使用 ANTLR4 4.9.3.1 的 C++ 运行时。
完整语法： https://s3.amazonaws.com/artifacts.openencypher.org/ M18/Cypher.g4
I looked at these and they don't seem to solve the problem:
Is there a way to know which alternative rule ANTLR parser is currently in?
How to know which alternative rule ANTLR parser is currently in during visit
For example:
oC_ListOperatorExpression :
( SP IN SP? oC_PropertyOrLabelsExpression )
| ( SP? '[' oC_Expression ']' )
| ( SP? '[' oC_Expression? '..' oC_Expression? ']' ) ;
In this particular case, alternative 2 and alternative 3 have no special tokens or tokens in a fixed position I can leverage to differentiate them.
How can I tell which alternative am I using in the following without changing the grammar?
antlrcpp::Any visitOC_ListOperatorExpression(
CypherParser::OC_ListOperatorExpressionContext* ctx) override {
}
I am using the c++ runtime of ANTLR4 4.9.3.1.
The full grammar:
https://s3.amazonaws.com/artifacts.opencypher.org/M18/Cypher.g4
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您可以在最后一个替代方案中向两个
oC_Expression添加标签。然后你可以检查它们是否存在。（或者甚至只是检查第二个
oC_ExpressionYou could add labels to the two
oC_Expressions in the last alternative. Then you could check for the presence/absence of those.(Or even just check for the 2nd
oC_Expression