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
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