From b0d92f44ea8cacce3817957ec40cd4d08a27a7f3 Mon Sep 17 00:00:00 2001
From: nathan moreau <nathan.moreau@m4x.org>
Date: Fri, 26 Jan 2018 09:25:17 +0100
Subject: [PATCH] Adding CCList.tail_opt

---
 src/core/CCList.ml        | 7 +++++++
 src/core/CCList.mli       | 4 ++++
 src/core/CCListLabels.mli | 4 ++++
 3 files changed, 15 insertions(+)

diff --git a/src/core/CCList.ml b/src/core/CCList.ml
index 064070d8..6f32f47e 100644
--- a/src/core/CCList.ml
+++ b/src/core/CCList.ml
@@ -855,6 +855,10 @@ let head_opt = function
   | [] -> None
   | x::_ -> Some x
 
+let tail_opt = function
+  | [] -> None
+  | _ :: tail -> Some tail
+
 let rec last_opt = function
   | [] -> None
   | [x] -> Some x
@@ -864,6 +868,9 @@ let rec last_opt = function
   (Some 1) (head_opt [1;2;3])
   (Some 1) (head_opt [1])
   None (head_opt [])
+  (Some [2;3]) (tail_opt [1;2;3])
+  (Some []) (tail_opt [1])
+  None (tail_opt [])
   (Some 3) (last_opt [1;2;3])
   (Some 1) (last_opt [1])
   None (last_opt [])
diff --git a/src/core/CCList.mli b/src/core/CCList.mli
index 8dba2044..d97a5888 100644
--- a/src/core/CCList.mli
+++ b/src/core/CCList.mli
@@ -249,6 +249,10 @@ val head_opt : 'a t -> 'a option
 (** First element.
     @since 0.20 *)
 
+val tail_opt : 'a t -> 'a t option
+(** Return the given list without its first element.
+    @since NEXT_RELEASE *)
+    
 val last_opt : 'a t -> 'a option
 (** Last element.
     @since 0.20 *)
diff --git a/src/core/CCListLabels.mli b/src/core/CCListLabels.mli
index 66f477c0..995c3be7 100644
--- a/src/core/CCListLabels.mli
+++ b/src/core/CCListLabels.mli
@@ -159,6 +159,10 @@ val head_opt : 'a t -> 'a option
 (** First element.
     @since 0.20 *)
 
+val tail_opt : 'a t -> 'a t option
+(** Return the given list without its first element.
+    @since NEXT_RELEASE *)
+
 val last_opt : 'a t -> 'a option
 (** Last element.
     @since 0.20 *)