private void resolveGroup(){
  OppNode top;
  while ((top=oppStack.remove(0)) != null) {
    top.popValues(nodeStack);
    nodeStack.add(0,top);
  }
}

private void resolveGroup ( ) { OppNode top ; while ( ( top = oppStack . remove ( 0 ) ) != null ) { top . popValues ( nodeStack ) ; nodeStack . add ( 0 , top ) ; } }
resolves all pending opp nodes on the stack until the next group marker is reached .
