Hi Joel Li,
I'm also new to ANTLR and had a look at your problem to learn more...
This modified grammar seems to work for me (at least AntlrWorks Interpreter
shows the correct tree):
=================
grammar TestComment;
all : (txt)*;
txt : comment {System.out.println("found comment");}
| content {System.out.println("found content");}
| NEWLINE
;
comment : COMMENT_TAG STRING NEWLINE
;
content : STRING NEWLINE
;
COMMENT_TAG
: '#';
NEWLINE : '\r'? '\n';
STRING : ~COMMENT_TAG ~('\n'|'\r')*
;
========================
The problem is, that STRING is not allowed to start with a COMMENT_TAG,
because otherwise there would be no difference between a comment and
content. Please also note the addition of just a NEWLINE to txt, which
allows for empty lines, too.
HTH,
Stefan
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Von: [email protected]
[mailto:[email protected]] Im Auftrag von ???
Gesendet: Freitag, 10. Dezember 2010 03:07
An: [email protected]
Betreff: [antlr-interest] useing antlr to get key information from
commentline
i am new to antlr. i put key infomation in the comment and try to use antlr
to retrive comment in text file.
here is the grammar:
grammar T;
options {backtrack=true;}
all : (txt)*;
txt :comment {System.out.println("found comment");}
|content {System.out.println("found content");}
;
comment
: COMMENT_TAG content
;
content
: STRING NEWLINE
;
COMMENT_TAG
: '#'
;
NEWLINE: ('\r'? '\n')+;
STRING
: ('\u0010'..'\uffff')*
;
the input text like this :
#command parameter parameter
hello,this is text;
it dose not work,the output is
found content
found content
my expectation is follow :
found comment
found content
.
how to modify the grammar?
Regards
Joel li
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