static int getIndex(String[] list, String elem) {
    for(int i=0; i < list.length; i++) {
      if (list[i] != null && list[i].toLowerCase().equals(elem)) {
        return i;
      }
    }
    return -1;
  }
Performs a descent of the leftmost branch of a tree, stopping when either a
node with a non-null token is found or the leaf level is encountered.

@param tree
         candidate node from which to start searching

@return node at which descent stopped
ql/src/java/org/apache/hadoop/hive/ql/parse/ParseUtils.java