[antlr-interest] Re: AST typecasting problem?

[lgcraymer]

The most likely cause is (from
http://www.antlr.org/doc/trees.html#_bb3 in the ANTLR manual):

"If you are only interested in specifying the AST node type at
runtime, use the

setASTNodeType(String className)

method on the parser or factory.  By default, trees are constructed of
nodes of type antlr.CommonAST. (You must use the fully-qualified class
name)."

Do that in the parser and you should be okay:  my guess is that your
parser is generating CommonAST nodes (the default).

--Loring

--- In antlr-interest at yahoogroups.com, "Steve" <stevegianvecchio at h...>
wrote:
> 
> 
> I created this file:
> 
> public class BeliefAST extends antlr.CommonAST {
>     List beliefList;
> }
> 
> Then in a separated file:
> 
> ...
> AST t1 = parser.getAST();
> BeliefAST t2 = (BeliefAST)t1;
> System.out.println("I don't get here.");
> 
> At the second line, where the typecast takes place, my program exits 
> immediately without any errors.  The following code works fine:
> 
> ...
> AST t1 = parser.getAST();
> CommonAST t2 = (CommonAST)t1;
> System.out.println("I don't get here.");
> 
> I can't think of what I'm doing wrong.  I tried replacing my 
> BeliefAST file with CommonAST and just changing the text "CommonAST" 
> to "BeliefAST" and got the same result.  I can't seem to figure out 
> what is causing this, anyone have any ideas?





 
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