[antlr-interest] add new support methods in BaseTree?

[Terence Parr]

Hi, i'm thinking of adding this to BaseTree:

     /** Walk upwards looking for ancestor of this token type */
     public boolean hasAncestor(int ttype) {
         CommonTree t = this;
         t = t.parent;
         while ( t!=null ) {
             if ( t.getType()==ttype ) return true;
             t = t.parent;
         }
         return false;
     }

and perhaps a few more context computations.    In a tree grammar, you  
might want to do this:

{((VecMathNode)input.LT(1)).hasAncestor(PRINT)}? ID // match only IDs  
in expr of print statements

Any objections or votes in support?

Ter