+=== Word: ROLL
+
+....
+Data stack: ( vu...v1 v0 u -- ...v1 v0 vu )
+....
+
+"ROLL" is a function word that "moves" the u:th data stack cell down
+from top onto the data stack while discarding it. 0 indicates the top
+cell; 1 indicates the second top cell making it the same as
+<<p_swap,SWAP>>; 2 indicates the third top cell making it the same as
+<<p_rot,ROT>>.
+
+