- * @param tag the tag for the output tree
- * @param e the elements to match
- * @param drops only elements of <tt>e</tt> whose corresponding <tt>boolean</tt> in <tt>drops</tt>
- * is <i>false</i> will be included in the output tree
+ * @param tag the tag for the output tree
+ * @param e the elements to match
+ * @param drops only elements of <tt>e</tt> whose corresponding <tt>boolean</tt> in <tt>drops</tt>
+ * is <i>false</i> will be included in the output tree
+ * @param unwrap if true, all children of the last child (ie
+ * grandchildren) are promoted to children of this node; this is very useful for matching repetitions