[antlr-interest] ClassCastException with custom node type

[Stefan Mätje (d)]

Am 05.07.2012 11:22:55 schrieb(en) Ale Strooisma:
> Thanks for your reply,
> 
> I didn't see much difference between your and my code, and when I added 
> the line "nodes.setTokenStream(tokens);" the problem was still there. 
> Please see my code below.
> 
> Kind Regards, Ale

I don't see much difference also. Perhaps the difference comes from the tree 
adaptor. I'll paste my adaptor below. Maybe that helps?

-----8<-----------8<-----------8<-----------8<---------8<---------8<--------
import org.antlr.runtime.*;
import org.antlr.runtime.tree.CommonTreeAdaptor;

/** A tree adaptor that tells ANTLR to build Pearl90Tree nodes. Derived from
    http://www.antlr.org/wiki/display/ANTLR3/Tree
+construction#Treeconstruction-UsingcustomASTnodetypes
    */
public class Pearl90TreeAdaptor extends CommonTreeAdaptor {

    public Object create(Token token) {
        return new Pearl90Tree(token);
    }

    /** Of the following create() methods only the third is used atm. by the
        program. The apparently unused ones are added to the implementation 
but
        print some information. All are used but 1 & 2 triggered by hand from
        parser only.
        */
    public Object create(int tokenType, Token fromToken) {
        fromToken = createToken(fromToken);
        fromToken.setType(tokenType);
        // System.err.println("1 Create node"+fromToken.toString());
        return this.create(fromToken);
    }

    public Object create(int tokenType, Token fromToken, String text) {
        if (fromToken == null) return create(tokenType, text);
        fromToken = createToken(fromToken);
        fromToken.setType(tokenType);
        fromToken.setText(text);
        // System.err.println("2 Create node"+fromToken.toString());
        return this.create(fromToken);
    }

    public Object create(int tokenType, String text) {
        Token fromToken = createToken(tokenType, text);
        // System.err.println("3 Create node"+fromToken.toString()+text
+tokenType);
        return this.create(fromToken);
    }

    public Object dupNode(Object t) {
        if (null == t) {
            return null;
        }
        return create(((Pearl90Tree)t).token);
    }

    public Object errorNode(TokenStream input, Token start, Token stop,
        RecognitionException e)
    {
        Pearl90ErrorNode t = new Pearl90ErrorNode(input, start, stop, e);
        System.out.println("returning error node '"+t+"' @index="+input.index
());
        return t;
    }

}
-----8<-----------8<-----------8<-----------8<---------8<---------8<--------

> TreeAdaptor adaptor = new ASTNodeAdaptor();
> 
> System.out.println("Starting Lexer... ");
> WcLexer lexer = new WcLexer(new ANTLRInputStream(fileInputStream));
> TokenStream tokens = new CommonTokenStream(lexer);
> 
> System.out.println("Starting Parser... ");
> WcParser parser = new WcParser(tokens);
> parser.setTreeAdaptor(adaptor);
> WcParser.program_return result = parser.program();
> ASTNode tree = (ASTNode) result.getTree();
> 
> System.out.println("Checking Context... ");
> CommonTreeNodeStream nodes = new CommonTreeNodeStream(adaptor, tree);
> nodes.setTokenStream(tokens);
> WcChecker checker = new WcChecker(nodes,f);
> checker.program();
> 
> 
> On 07/05/2012 10:05 AM, Stefan Mätje wrote:
> > Hi,
> >
> > the attachment seems to be stripped by the mailing list. I'll put it now
> > directly in the message.
> >
> > My classes are
> >       Pearl90Tree        a tree node
> >       Pearl90TreeAdaptor    the node factory?
> >       Pearl90ErrorNode    the error node object
> >
> > Code excerpt follows, sorry for line wraps:
> > {
> >       // ==== Prepare tree node adaptor for later use =========
> >       Pearl90TreeAdaptor pearl90Adaptor = new Pearl90TreeAdaptor();
> >
> >       // SNIP-SNAP
> >
> >       // ==== PARSER STAGE ====================================
> >       // Create a stream of tokens fed by the lexer
> >       // But use TokenRewriteStream if we need to change the AST
> >       // with a tree grammar later. See ANTLR Ref p. 224
> >       CommonTokenStream tokens = new CommonTokenStream(lexer);
> >
> >       // Create a parser that feeds off the token stream
> >       parser = new Pearl90Parser(tokens);
> >
> >       // Use my own tree adaptor to build Pearl90Tree nodes in the AST.
> >       parser.setTreeAdaptor(pearl90Adaptor);
> >
> >       // Begin parsing at rule "file" and get return value
> >       Pearl90Parser.file_return r = parser.file();
> >       // Change the returned value to an AST
> >       Pearl90Tree ast = (Pearl90Tree)r.getTree();
> >
> >       // SNIP-SNAP
> >
> >       // ---------------------------------------
> >       // Do error accounting ...
> >       // SNIP-SNAP
> >
> >       // ==== Symbol Table Generation =========================
> >       // This stage fills the symbol table and may rewrite the AST
> >       // based on its findings.
> >       // CommonTreeNodeStream nodes = new CommonTreeNodeStream(ast);
> >       CommonTreeNodeStream nodes = new
> > CommonTreeNodeStream(pearl90Adaptor, ast);
> >       nodes.setTokenStream(tokens);
> >       // This line fixed crash on spurious CommonToken insertions.
> > Already done
> >       // now by constructor above.
> >       //nodes.setTreeAdaptor(pearl90Adaptor);
> >
> >       SymbolTable symtab = new SymbolTable();
> >       // Use my custom constructor for AST tree parser
> >       // Use workaround with new for missing debug output stream...
> >       Pearl90Sym syms = new Pearl90Sym(nodes, symtab, new
> > PrintWriter(System.out,true));
> >
> >       // Use my own tree adaptor to build Pearl90Tree nodes in the AST.
> >       syms.setTreeAdaptor(pearl90Adaptor);
> >
> >       // Trigger symtab actions upon certain subtrees,
> >       // return the rewritten AST as directed by Pearl90Sym.g
> >       ast = (Pearl90Tree)syms.downup(ast);
> >
> >
> > }
> >
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> 
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