Implement reverse mapping from preorder to nodes.

[tatoo.git] / src / tree.ml

diff --git a/src/tree.ml b/src/tree.ml
index d44755e..97711dd 100644 (file)
--- a/src/tree.ml
+++ b/src/tree.ml
@@ -107,5 +107,9 @@ sig
   (** [preorder t n] returns the pre-order position of [n] in [t].
       [preodrder t (root t) == 0] and [preorder t nil < 0].
   *)
+
+  val by_preorder : t -> int -> node
+  (** [by_preorder t i] returns the node with preorder [i]
+  *)
   val print_node : Format.formatter -> node -> unit
 end