[antlr-interest] Beginners Question

[decoder]

 Hello List,


I've recently started working with ANTLR because I need a JavaScript
parser (in Java). So I took the grammar at
http://www.antlr.org/grammar/1206736738015/JavaScript.g and used antlr3
to generate Java Classes from that. I figured out that I need Lexer and
Parser classes and have something like the code at the end of the mail.

The problem with this is that the returned "tree" is not a tree but a
flat list. It contains all tokens but flattened, I assumed that you
should get a real tree though, am I wrong there?

My goal for now would be to extract for example all things that are
"IfStatement" from the grammar, but I can't see how I can achieve that :(

I'd appreciate any help :)

Thanks and Regards,


Chris


public static CommonTree parseJava(String filename) throws
RecognitionException {
               ANTLRFileStream fs = null;
               try {
            fs = new ANTLRFileStream(filename);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        final TreeAdaptor adaptor = new CommonTreeAdaptor() {
            public Object create(Token payload) {
                CommonTree t = new CommonTree(payload);
                return t;
            }
        };
        JavaScriptLexer lex = new JavaScriptLexer(fs);
        TokenRewriteStream tokens = new TokenRewriteStream(lex);
        JavaScriptParser grammar = new JavaScriptParser(tokens);
        JavaScriptParser.program_return ret = null;
               grammar.setTreeAdaptor(adaptor);
               StdErrReporter errorReporter = new StdErrReporter();
        grammar.setErrorReporter(errorReporter);
        lex.setErrorReporter(errorReporter);
               ret = grammar.program();
               if (errorReporter.error()) {
            printTree((CommonTree) ret.getTree(), 0);
            throw new RuntimeException("Parser/Lexer failure");
        }
               return (CommonTree)ret.getTree();
    }