解析器规则和词法分析器规则之间的替代

问题描述

该问题埋在另一个问题的更新部分中，现在专门问这个问题.

The question is buried in the update section of another question, now specifically ask it.

我正在使用antlr3.4.

I am using antlr3.4.

我有一个简单的语法试图解析2种类型的文本，该行以"#include"开头，还有其他.这是我的语法:

I have a simple grammar trying to parse 2 types of text, the line started with "#include" and others. Here is my grammar:

:

The warning means that input like foo" (a FILE_NAME followed by a DOUBLE_QUOTE) can be matched by the parser in more than one way:


 ANTLR将选择贪婪解析，但是由于可能出现贪婪，因此会生成警告.如果您明确告诉解析器贪婪地进行匹配，则不会再发出警告:
ANTLR will choose the greedy parse, but since an ungreedy is possible, a warning is generated. If you explicitly tell the parser to match greedily, the warning would not be issued anymore:
other_cmd
 : (options {greedy=true;} : ~INCLUDE)+
 ;
不，据我所知.这个警告确实是个神秘的事物.替代方法通常表示解析器可以遵循的分支:
No, not as far as I know. This warning is indeed rather cryptic. Alternatives usually denote the branches the parser can follow:
parser_rule
 : alternative_1
 | alternative_2
 | alternative_3
 ;
但是在您的情况下，ANTLR似乎在谈论令牌范围是替代方案:DOUBLE_QUOTE..FILE_NAME是替代方案，New_Line..WS是第二替代方案.
But in your case, it seems ANTLR is talking about token ranges being the alternatives: DOUBLE_QUOTE..FILE_NAME being an alternative and New_Line..WS being the 2nd.
                        
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