From 84af4f6f2e6a2f34941c8d53448f1a40b80c4b95 Mon Sep 17 00:00:00 2001
From: Emm <emmanuel.surleau@gmail.com>
Date: Sun, 25 Jan 2015 22:56:54 +0100
Subject: [PATCH] Use pattern-matching instead of List.hd and List.tl.

---
 src/misc/roseTree.ml | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/misc/roseTree.ml b/src/misc/roseTree.ml
index 242281e2..23aca6eb 100644
--- a/src/misc/roseTree.ml
+++ b/src/misc/roseTree.ml
@@ -58,13 +58,13 @@ module Zipper = struct
   let tree zipper = zipper.tree
 
   let left_sibling zipper =
-    match zipper.lefts with
+    let rev_lefts = List.rev zipper.lefts in
+    match rev_lefts with
     | []    -> None
-    | lefts ->
-      let rev_lefts = List.rev lefts in
+    | last_left::tail_rev_lefts ->
       Some {
-        tree = List.hd rev_lefts ;
-        lefts = List.tl rev_lefts |> List.rev ;
+        tree = last_left ;
+        lefts = tail_rev_lefts |> List.rev ;
         rights = zipper.tree::zipper.rights ;
         parents = zipper.parents
       }