I am using Antlr4 to parse C code and I am using the following grammar to parse:
Link to C.g4
The above grammar by default does not provide any parsing rules to get preprocessor statements.
I changed the grammar slightly to get the preprocessor lines by adding the following lines
externalDeclaration
: functionDefinition
| declaration
| ';' // stray ;
| preprocessorDeclaration
;
preprocessorDeclaration
: PreprocessorBlock
;
PreprocessorBlock
: '#' ~[\r\n]*
-> channel(HIDDEN)
;
And in Java I am using the following listener to get the preprocessor lines
@Override
public void enterPreprocessorDeclaration(PreprocessorDeclarationContext ctx) {
System.out.println("Preprocessor Directive found");
System.out.println("Preprocessor: " + parser.getTokenStream().getText(ctx));
}
The method is never triggered. Can someone suggest a method to get the preprocessor lines?
Input:
#include <stdio.h>
int k = 10;
int f(int a, int b){
int i;
for(i = 0; i < 5; i++){
printf("%d", i);
}
}
Actually, with channel(HIDDEN)
, the rule preprocessorDeclaration
produces no output.
If I remove -> channel(HIDDEN)
, it works :
preprocessorDeclaration
@after {System.out.println("Preprocessor found : " + $text);}
: PreprocessorBlock
;
PreprocessorBlock
: '#' ~[\r\n]*
// -> channel(HIDDEN)
;
Execution :
$ 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);
}
}
In file CMyListener.java
(from my previous answer) I have added :
public void enterPreprocessorDeclaration(CParser.PreprocessorDeclarationContext ctx) {
System.out.println("Preprocessor Directive found");
System.out.println("Preprocessor: " + parser.getTokenStream().getText(ctx));
}
Execution :
$ 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;
...
}