想跳过除antlr4语法中的两个以外的所有行注释(want to skip all line comments except two in antlr4 grammar)

我想稍微扩展IDL.g4语法，以便区分以下两个注释//@top-level false和//@top-level true ，所有其他注释我只想像以前一样跳过。

我试图像这样添加top_level ， TOP_LEVEL_TRUE和TOP_LEVEL_FALSE ，因为我认为antr4优先考虑首先出现的词法规则。

top_level : TOP_LEVEL_TRUE | TOP_LEVEL_FALSE ; TOP_LEVEL_TRUE : '//@top-level true' ; TOP_LEVEL_FALSE : '//@top-level false' ; LINE_COMMENT : '//' ~('\n'|'\r')* '\r'? '\' -> channel(HIDDEN) ;

但是从不调用侦听器enterTop_level(...) ，所有注释似乎都被LINE_COMMENT吃掉了。我该如何组织词法分析器和解析器规则？

还有一个问题，我还希望在到达输入文件结束时收到通知。我怎么做？我在侦听器类中尝试了一个finalize()函数，但从未调用过。

更新了一个完整的示例：

我使用这个语法文件： IDL.g4如上所述。然后我通过将解析器规则top_level放在event_header规则下面来更新它。 Lexer规则放在ID规则的正上方。

这是我的Listener.java文件

class Listener extends IDLBaseListener { @Override public void enterTop_level(IDLParser.Top_levelContext ctx) { System.out.println("Found top-level"); } }

这是一个主程序：IDLCheck.java

import org.antlr.v4.runtime.*; import org.antlr.v4.runtime.tree.ParseTreeWalker; import java.io.FileInputStream; import java.io.InputStream; public class IDLCheck { public void process(String[] args) throws Exception { InputStream is = new FileInputStream("sample.idl"); ANTLRInputStream input = new ANTLRInputStream(is); IDLLexer lexer = new IDLLexer(input); CommonTokenStream tokens = new CommonTokenStream(lexer); IDLParser parser = new IDLParser(tokens); parser.setBuildParseTree(true); RuleContext tree = parser.specification(); Listener listener = new Listener(); ParseTreeWalker walker = new ParseTreeWalker(); walker.walk(listener, tree); } public static void main(String[] args) throws Exception { new IDLCheck().process(args); } }

和输入文件：sample.idl

module CommonTypes { struct WChannel { int w; float d; }; //@top-level false struct EPlanID { int kind; short index; }; //@top-level TRUE };

我希望看到输出“发现顶级”两次，但我什么也看不见

I want to extend the IDL.g4 grammar a bit so that I can distinguish the following two comments //@top-level false and //@top-level true, all other comments I just want to skip like before.

I have tried to add top_level, TOP_LEVEL_TRUEand TOP_LEVEL_FALSElike this, because I thought antr4 gave precedence to lexical rules comming first.

top_level : TOP_LEVEL_TRUE | TOP_LEVEL_FALSE ; TOP_LEVEL_TRUE : '//@top-level true' ; TOP_LEVEL_FALSE : '//@top-level false' ; LINE_COMMENT : '//' ~('\n'|'\r')* '\r'? '\' -> channel(HIDDEN) ;

But the listener enterTop_level(...) is never called, all comments seems to be eaten by LINE_COMMENT. How shall I organize the lexer and parser rules?

And one more question, I also want to be notified when end of input-file is reached. How do I do that? I have tried a finalize() function i the listener class, but never get called.

Updated with a complete example:

I use this grammar file : IDL.g4 as I said above. Then I update it by putting the parser rule top_level just below the event_header rule. The Lexer rules is put just above the ID rule.

Here is my Listener.java file

class Listener extends IDLBaseListener { @Override public void enterTop_level(IDLParser.Top_levelContext ctx) { System.out.println("Found top-level"); } }

and here is a main program: IDLCheck.java

import org.antlr.v4.runtime.*; import org.antlr.v4.runtime.tree.ParseTreeWalker; import java.io.FileInputStream; import java.io.InputStream; public class IDLCheck { public void process(String[] args) throws Exception { InputStream is = new FileInputStream("sample.idl"); ANTLRInputStream input = new ANTLRInputStream(is); IDLLexer lexer = new IDLLexer(input); CommonTokenStream tokens = new CommonTokenStream(lexer); IDLParser parser = new IDLParser(tokens); parser.setBuildParseTree(true); RuleContext tree = parser.specification(); Listener listener = new Listener(); ParseTreeWalker walker = new ParseTreeWalker(); walker.walk(listener, tree); } public static void main(String[] args) throws Exception { new IDLCheck().process(args); } }

and a input file: sample.idl

module CommonTypes { struct WChannel { int w; float d; }; //@top-level false struct EPlanID { int kind; short index; }; //@top-level TRUE };

I expect to see the output "Found top-level" twice, but I see nothing

最满意答案

最后我找到了解决方案。我刚刚在TOP_LEVEL_FALSE和TOP_LEVEL_TRUE词法分析器规则中添加了换行符，我还将top_level解析器规则添加到定义规则中，因为我只希望top_level出现在struct或union之后。这是IDL格式的rti.com特定扩展，这个修改对我来说似乎已经足够了。

definition : type_decl SEMICOLON top_level? | const_decl SEMICOLON ... TOP_LEVEL_TRUE : '//@top-level true' '\r'? '\n' ; TOP_LEVEL_FALSE : '//@top-level false' '\r'? '\n' ;

Finally I found a solution. I just added newline characters to the TOP_LEVEL_FALSE and TOP_LEVEL_TRUElexer rules an I also added the top_level parser rule to the definition rule because I only expected top_level to appear after a struct or union. this is a rti.com specific extension to the IDL-format, this modification seems to be good enough for me.

definition : type_decl SEMICOLON top_level? | const_decl SEMICOLON ... TOP_LEVEL_TRUE : '//@top-level true' '\r'? '\n' ; TOP_LEVEL_FALSE : '//@top-level false' '\r'? '\n' ;

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