检查方法是否有带antlr的注释

Question

对Java.g4的更改

文件开头

grammar Java;


@lexer::members {
    public static final int WHITESPACE = 1;
    public static final int COMMENTS = 2;
}

文件末尾

//
// Whitespace and comments
//

WS  :  [ \t\r\n\u000C]+ -> channel(WHITESPACE) ;  // channel(1)

COMMENT    :   '/*' .*? '*/' -> channel(COMMENTS)  ; // channel(2)

LINE_COMMENT    :   '//' ~[\r\n]* -> channel(COMMENTS) ;   // channel(2)

尝试将注释和空格发送到不同的通道，如"The Definitive ANTLR 4 Reference“一书中所述，第12.1章在不同通道上广播令牌

执行antlr4 Java.g4时，将显示以下错误

java org.antlr.v4.Tool Java.g4
    warning(155): Java.g4:1017:35: rule WS contains a lexer command with an unrecognized constant value; lexer interpreters may produce incorrect output
    warning(155): Java.g4:1019:40: rule COMMENT contains a lexer command with an unrecognized constant value; lexer interpreters may produce incorrect output
    warning(155): Java.g4:1021:45: rule LINE_COMMENT contains a lexer command with an unrecognized constant value; lexer interpreters may produce incorrect output

我看不出有什么问题？

Answer 1

您应该替换以下片段：

@lexer::members {
    public static final int WHITESPACE = 1;
    public static final int COMMENTS = 2;
}

使用字符串：

channels { WHITESPACE, COMMENTS }

Answer 2

解决方案是拆分lexer和parser文件。并且作为kvanttt在lexer文件中使用channels { WHITESPACE, COMMENTS }，完整的文件将被上传到我的https://github.com/nkv123/grammars-v4分支存储库。