我正在使用Antlr4来解析C代码,并且使用以下语法来解析:
链接到 C.g4
默认情况下,上述语法不提供任何解析规则来获取预处理器语句。
我稍微更改了语法,通过添加以下行来获取预处理器行
externalDeclaration
: functionDefinition
| declaration
| ';' // stray ;
| preprocessorDeclaration
;
preprocessorDeclaration
: PreprocessorBlock
;
PreprocessorBlock
: '#' ~[rn]*
-> channel(HIDDEN)
;
在 Java 中,我使用以下侦听器来获取预处理器行
@Override
public void enterPreprocessorDeclaration(PreprocessorDeclarationContext ctx) {
System.out.println("Preprocessor Directive found");
System.out.println("Preprocessor: " + parser.getTokenStream().getText(ctx));
}
永远不会触发该方法。有人可以建议一种获取预处理器行的方法吗?
输入:
#include <stdio.h>
int k = 10;
int f(int a, int b){
int i;
for(i = 0; i < 5; i++){
printf("%d", i);
}
}
实际上,对于channel(HIDDEN)
,规则preprocessorDeclaration
不产生输出。
如果我删除-> channel(HIDDEN)
,它可以工作:
preprocessorDeclaration
@after {System.out.println("Preprocessor found : " + $text);}
: PreprocessorBlock
;
PreprocessorBlock
: '#' ~[rn]*
// -> channel(HIDDEN)
;
执行:
$ grun C compilationUnit -tokens -diagnostics t2.text
[@0,0:17='#include <stdio.h>',<PreprocessorBlock>,1:0]
[@1,18:18='n',<Newline>,channel=1,1:18]
[@2,19:19='n',<Newline>,channel=1,2:0]
[@3,20:22='int',<'int'>,3:0]
...
[@72,115:114='<EOF>',<EOF>,10:0]
C last update 1159
Preprocessor found : #include <stdio.h>
line 4:11 reportAttemptingFullContext d=83 (parameterDeclaration), input='int a,'
line 4:11 reportAmbiguity d=83 (parameterDeclaration): ambigAlts={1, 2}, input='int a,'
...
#include <stdio.h>
int k = 10;
int f(int a, int b) {
int i;
for(i = 0; i < 5; i++) {
printf("%d", i);
}
}
在文件CMyListener.java
(来自我之前的答案)中,我添加了:
public void enterPreprocessorDeclaration(CParser.PreprocessorDeclarationContext ctx) {
System.out.println("Preprocessor Directive found");
System.out.println("Preprocessor: " + parser.getTokenStream().getText(ctx));
}
执行:
$ java test_c t2.text
...
parsing ended
>>>> about to walk
Preprocessor Directive found
Preprocessor: #include <stdio.h>
>>> in CMyListener
#include <stdio.h>
int k = 10;
...
}