[antlr-interest] Custom AST node type - guidance needed

[Junkman]

Hi Bill,

You have

import antlr.*;

instead of

import org.antlr.runtime.*;

Maybe that's the problem?

org.antlr.runtime.CommonToken implements org.antlr.runtime.Token, so
explicit casting seems out of wack.

Jay


Bill Andersen wrote:
> Thanks John
> 
> Below is my class def..  Eclipse tells me the casts to Token below are required.  Running a grammar that executes these constructors tells me I can't cast to Token.
> 
> Here's a sample tree building expression where this class is used.
> 
> 	^(AS_TYPE_LIST<ASNode>[s.getType($ID.text)] ID)
> 
> the getType method just looks up a ASType object by name from a table.
> 
> import org.antlr.runtime.tree.*;
> 
> import antlr.*;
> 
> public class ASNode extends CommonTree {
> 	
> 	public ASType type = null;
> 	
> 	public ASNode() { }
> 	
> 	public ASNode(int ttype, ASType type) {
> 		token = (Token) new CommonToken(ttype,"");
> 		this.type = type;
> 	}
> 	
> 	public ASNode(int ttype) {
> 		token = (Token) new CommonToken(ttype,"");
> 	}
> 	
> 	@Override
> 	public String toString() {
> 		return (token!=null?token.getText():"")+"<ASNode>;"+type;
> 	}
> 
> 	@Override
> 	public Tree dupNode() {
> 		ASNode n = new ASNode();
> 		n.token = token;
> 		n.type = type;
> 		return n;
> 	}
> 	
> }
> 
> On Jul 19, 2010, at 15:15 , John B. Brodie wrote:
> 
>> On Mon, 2010-07-19 at 14:29 -0400, Bill Andersen wrote:
>>> Hi folks
>> Greetings!
>>
>>> Having some trouble making ASTs using a custom node type.  Before I ask any stupid questions, what is the best place to look on how to do this ( I'm using 3.2 )?  I'm finding bits and pieces, some of them contradictory.  For example I find this example
>>>
>>> static class V extends CommonTree {
>>>  public int x,y,z;
>>>  public V(int ttype, int x, int y, int z) {
>>>    this.x=x; this.y=y; this.z=z; token=new CommonToken(ttype,"");
>>>  }
>>> at http://www.antlr.org/wiki/display/ANTLR3/Tree+construction
>>>
>>> When I try to define a constructor like this I'm forced to put a cast between on CommonToken to Token, which causes a runtime can't cast error.
>>>
>>> What I want is really quite simple.  Need to add one extra field to my AST nodes to carry DSL type information.
>>>
>>> Any help appreciated.  Thanks.
>> Unable to reproduce.
>>
>> Attached please find a complete example derived from the grammar on the
>> above wiki page that uses the class V. maybe I'm using a different
>> example than yours?
>>
>> Need more info....
>>   -jbb
>>
>> <T.g>
> 
> Bill Andersen 
> Highfleet, Inc. (www.highfleet.com)
> 3600 O'Donnell Street, Suite 600
> Baltimore, MD 21224
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