更新时间:2022-06-24 10:14:24
当您只对要解析的文件的一部分感兴趣时,则不需要解析器,也无需为整个格式编写语法文件.仅词法语法和ANTLR的options{filter=true;}
就足够了.这样,您将仅获取在语法中定义的标记,而忽略文件的其余部分.
When you're only interested in a part of the file you're parsing, you don't need a parser and write a grammar for the entire format of the file. Only a lexer-grammar and ANTLR's options{filter=true;}
will suffice. That way, you will only grab the tokens you defined in your grammar and ignore the rest of the file.
这是一个快速演示:
lexer grammar TestLexer;
options{filter=true;}
@lexer::members {
public static void main(String[] args) throws Exception {
String text =
"7114422 2009-07-16 15:43:07,078 [LOGTHREAD] INFO StatusLog - Task 0 input : uk.project.Evaluation.Input.Function1(selected=[\"red\",\"yellow\"]){}\n"+
"\n"+
"7114437 2009-07-16 15:43:07,093 [LOGTHREAD] INFO StatusLog - Task 0 output : uk.org.project.Evaluation.Output.Function2(selected=[\"Rocket\"]){}\n"+
"\n"+
"7114422 2009-07-16 15:43:07,078 [LOGTHREAD] INFO StatusLog - Task 0 input : uk.project.Evaluation.Input.Function3(selected=[\"blue\",\"yellow\"]){}\n"+
"\n"+
"7114437 2009-07-16 15:43:07,093 [LOGTHREAD] INFO StatusLog - Task 0 output : uk.org.project.Evaluation.Output.Function4(selected=[\"Speech\"]){}";
ANTLRStringStream in = new ANTLRStringStream(text);
TestLexer lexer = new TestLexer(in);
CommonTokenStream tokens = new CommonTokenStream(lexer);
for(Object obj : tokens.getTokens()) {
Token token = (Token)obj;
System.out.println("> token.getText() = "+token.getText());
}
}
}
Input
: 'Evaluation.Input.Function' '0'..'9'+ Params
;
Output
: 'Evaluation.Output.Function' '0'..'9'+ Params
;
fragment
Params
: '(selected=[' String ( ',' String )* '])'
;
fragment
String
: '"' ( ~'"' )* '"'
;
现在做:
javac -cp antlr-3.2.jar TestLexer.java
java -cp .:antlr-3.2.jar TestLexer // or on Windows: java -cp .;antlr-3.2.jar TestLexer
,您将看到以下内容打印到控制台:
and you'll see the following being printed to the console:
> token.getText() = Evaluation.Input.Function1(selected=["red","yellow"])
> token.getText() = Evaluation.Output.Function2(selected=["Rocket"])
> token.getText() = Evaluation.Input.Function3(selected=["blue","yellow"])
> token.getText() = Evaluation.Output.Function4(selected=["Speech"])