模棱两可的ANTLR解析器规则

问题描述

我有一个非常简单的示例文本，我想用ANTLR进行解析，但是由于规则的定义不明确，我得到了错误的结果.

I have a very simple example text which I want to parse with ANTLR, and yet I'm getting wrong results due to ambiguous definition of the rule.

这是语法:

grammar SimpleExampleGrammar;

prog : event EOF;

event : DEFINE EVT_HEADER eventName=eventNameRule;

eventNameRule : DIGIT+;

DEFINE : '#define';

EVT_HEADER : 'EVT_';

DIGIT                   :           [0-9a-zA-Z_];

WS     :   ('' | ' ' | '\r' | '\n' | '\t') -> channel(HIDDEN);

第一个文本示例:

#define EVT_EX1

第二个文本示例:

#define EVT_EX1
#define EVT_EX2

因此，第一个示例已正确解析.

So, the first example is parsed correctly.

但是，第二个示例不起作用，因为eventNameRule匹配下一个"#define ..."并且解析树不正确

However, the second example doesn't work, as the eventNameRule matches the next "#define ..." and the parse tree is incorrect

感谢帮助更改语法以正确解析语法的任何帮助.

Appreciate any help to change the grammar to parse this correctly.

谢谢，Busi

推荐答案

除了缺少的循环说明符之外，您的WS规则也存在问题.第一个alt匹配任何东西.删除那个.顺便说一句，给您的DIGIT规则起一个不同的名字.它不仅可以匹配数字.

Beside the missing loop specifier you also have a problem in your WS rule. The first alt matches anything. Remove that. And, btw, give your DIGIT rule a different name. It matches more than just digits.

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