From 391605f6195f92603ca960014db302dc79e6d24f Mon Sep 17 00:00:00 2001
From: letouzey
Date: Wed, 16 Apr 2003 22:19:15 +0000
Subject: une fonction list_skipn qui zappe les n premiers elements d'une liste

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@3930 85f007b7-540e-0410-9357-904b9bb8a0f7
---
 lib/util.ml  | 5 +++++
 lib/util.mli | 1 +
 2 files changed, 6 insertions(+)

(limited to 'lib')

diff --git a/lib/util.ml b/lib/util.ml
index 982546ca9c..6d9cf16b36 100644
--- a/lib/util.ml
+++ b/lib/util.ml
@@ -291,6 +291,11 @@ let list_lastn n l =
   in
   if len < n then failwith "lastn" else aux len l
 
+let rec list_skipn n l = match n,l with 
+  | 0, _ -> l 
+  | _, [] -> failwith "list_fromn"
+  | n, _::l -> list_skipn (pred n) l
+
 let list_prefix_of prefl l = 
   let rec prefrec = function
     | (h1::t1, h2::t2) -> h1 = h2 && prefrec (t1,t2)
diff --git a/lib/util.mli b/lib/util.mli
index e7a99acd27..a18608712f 100644
--- a/lib/util.mli
+++ b/lib/util.mli
@@ -102,6 +102,7 @@ val list_split3 : ('a * 'b * 'c) list -> 'a list * 'b list * 'c list
 val list_firstn : int -> 'a list -> 'a list
 val list_last : 'a list -> 'a
 val list_lastn : int -> 'a list -> 'a list
+val list_skipn : int -> 'a list -> 'a list 
 val list_prefix_of : 'a list -> 'a list -> bool
 (* [map_append f [x1; ...; xn]] returns [(f x1)@(f x2)@...@(f xn)] *)
 val list_map_append : ('a -> 'b list) -> 'a list -> 'b list
-- 
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