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隐藏令牌到默认通道 - AntlrV3

发布于 2024-08-20 06:10:07 字数 74 浏览 7 评论 0原文

假设我在隐藏通道中有空白（WS）。和仅对于特定规则，我希望也考虑空格，是是否可以在解析器中单独将 WS 引入该特定规则的默认通道？

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姐不稀罕 2024-08-27 06:10:07

查看路径问题的答案，注意我如何将 '\n' 放入解析器规则中。您也应该能够输入“”。现在，隐藏通道上的 WS 的所有选项是否都需要包含在规则中将是唯一需要关注的问题。

例如，

rulename : Token1 ' ' Token2 ' ' Token1 {place action here};

请注意，规则名称以小写字母开头，它是解析器规则，而“Token#”以大写字母开头，是词法分析器规则。在这个例子中，规则在不同的标记之间需要一个空格，我想你可以放置类似 (' '|'\t'|'\r'|'\n')+ 的东西，但我还没有尝试过这个，并且会留给你去尝试。

Have look at the answer for your path question, notice how I put a '\n' into the parser rule. You should be able to put ' ' as well. Now, do all the options for your WS on the hidden channel need to be in the rule would be the only concern.

rulename : Token1 ' ' Token2 ' ' Token1 {place action here};

Please note that the rule name starts with a lowercase letter and it is a parser rule while the "Token#" start with uppercase letter and are lexer rules. In between the different tokens the rule requires a space in this example, and I suppose you could put something like (' '|'\t'|'\r'|'\n')+ but I have not tried this and will leave that for you to attempt.

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笑着哭最痛 2024-08-27 06:10:07

查询隐藏标记流

您始终可以在 C++ 中

myrule: MYTOK { static_cast<antlr::CommonHiddenStreamToken*>(LT(1).get())->getHiddenAfter()->getType() == WS}? MYTOK

ie语义谓词将在匹配词法标记 MYTOK 后检查是否存在空格标记

You can always query the hidden token stream

ie in C++

myrule: MYTOK { static_cast<antlr::CommonHiddenStreamToken*>(LT(1).get())->getHiddenAfter()->getType() == WS}? MYTOK

The semantic predicate will check to see if there is a whitespace token after matching the lexical token MYTOK

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笔落惊风雨 2024-08-27 06:10:07

词法分析器规则按照它们在语法文件中列出的顺序进行评估。

这意味着你可以有这样的东西：

STRING_LITERAL: '"' NONCONTROL_CHAR* '"';   


fragment NONCONTROL_CHAR: LETTER | DIGIT | UNDERSCORE |  SPACE | BACKSLASH | MINUS | COMMA;
fragment LETTER: LOWER | UPPER;
fragment LOWER: 'a'..'z';
fragment UPPER: 'A'..'Z';
fragment DIGIT: '0'..'9';
fragment SPACE: ' ' | '\t';
fragment UNDERSCORE: '_';   
fragment MINUS:  '-';
fragment BACKSLASH: '\\';

COMMA: ',';     

NEWLINE: ('\r'? '\n')+ { $channel = HIDDEN; };
TERMINATOR  : ';';


WHITESPACE: SPACE+ { $channel = HIDDEN; };

LINE_COMMENT
    :   
    '//' ~('\n'|'\r')*  ('\r\n' | '\r' | '\n') 
    {
        $channel = HIDDEN;
    }
    |   
    '//' ~('\n'|'\r')*     
    {
        $channel = HIDDEN;
    }
    ;

正如你所看到的，字符串文字中可以有空格或制表符。然而，独立的空格或制表符将被发送到隐藏通道。

Lexer rules are evaluated in the order they are listed in your grammar file.

This means you can have something like this:

STRING_LITERAL: '"' NONCONTROL_CHAR* '"';   


fragment NONCONTROL_CHAR: LETTER | DIGIT | UNDERSCORE |  SPACE | BACKSLASH | MINUS | COMMA;
fragment LETTER: LOWER | UPPER;
fragment LOWER: 'a'..'z';
fragment UPPER: 'A'..'Z';
fragment DIGIT: '0'..'9';
fragment SPACE: ' ' | '\t';
fragment UNDERSCORE: '_';   
fragment MINUS:  '-';
fragment BACKSLASH: '\\';

COMMA: ',';     

NEWLINE: ('\r'? '\n')+ { $channel = HIDDEN; };
TERMINATOR  : ';';


WHITESPACE: SPACE+ { $channel = HIDDEN; };

LINE_COMMENT
    :   
    '//' ~('\n'|'\r')*  ('\r\n' | '\r' | '\n') 
    {
        $channel = HIDDEN;
    }
    |   
    '//' ~('\n'|'\r')*     
    {
        $channel = HIDDEN;
    }
    ;

As you can see a string literal can have space or tabs in it. However a stand alone space or tab will be sent to the HIDDEN channel.

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