void* result=nsnull;
const void* result=nsnull;
avlFirstThat(nsAVLNode* aNode, nsAVLNodeFunctor& aFunctor) {  void* result=nsnull;  if(aNode) {    result = avlFirstThat(aNode->mLeft,aFunctor);    if (result) {      return result;    }    result = aFunctor(aNode->mValue);    if (result) {      return result;    }    result = avlFirstThat(aNode->mRight,aFunctor);  }  return result;}