From 9c338f193e76aac9f69a04e1e97cea3f69a73051 Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Wed, 9 Mar 2016 19:45:38 +0100
Subject: [PATCH] add `CCString.rev`

---
 src/core/CCString.cppo.ml |  4 ++++
 src/core/CCString.mli     | 15 +++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/src/core/CCString.cppo.ml b/src/core/CCString.cppo.ml
index 0574eab9..1cbd0e73 100644
--- a/src/core/CCString.cppo.ml
+++ b/src/core/CCString.cppo.ml
@@ -50,6 +50,10 @@ let init n f =
 
 let length = String.length
 
+let rev s =
+  let n = length s in
+  init n (fun i -> s.[n-i-1])
+
 let rec _to_list s acc i len =
   if len=0 then List.rev acc
   else _to_list s (s.[i]::acc) (i+1) (len-1)
diff --git a/src/core/CCString.mli b/src/core/CCString.mli
index c036700e..10194703 100644
--- a/src/core/CCString.mli
+++ b/src/core/CCString.mli
@@ -63,6 +63,21 @@ val init : int -> (int -> char) -> string
   init 0 (fun _ -> assert false) = ""
 *)
 
+val rev : string -> string
+(** [rev s] returns the reverse of [s]
+    @since NEXT_RELEASE *)
+
+(*$Q
+  Q.printable_string (fun s -> s = rev (rev s))
+  Q.printable_string (fun s -> length s = length (rev s))
+*)
+
+(*$=
+  "abc" (rev "cba")
+  "" (rev "")
+  " " (rev " ")
+*)
+
 val of_gen : char gen -> string
 val of_seq : char sequence -> string
 val of_klist : char klist -> string