From e6399964cb628b705a8acf52223c4fd99229a43c Mon Sep 17 00:00:00 2001
From: Nicolas Pierron <nicolas.b.pierron@gmail.com>
Date: Mon, 28 Sep 2009 18:22:14 +0000
Subject: [PATCH] Add the zipLists and zipListsWith functions.

svn path=/nixpkgs/trunk/; revision=17476
---
 pkgs/lib/lists.nix | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/pkgs/lib/lists.nix b/pkgs/lib/lists.nix
index 012b95ad061..785e47e7d52 100644
--- a/pkgs/lib/lists.nix
+++ b/pkgs/lib/lists.nix
@@ -127,5 +127,13 @@ rec {
       else { right = t.right; wrong = [h] ++ t.wrong; }
     ) { right = []; wrong = []; };
 
-    
+
+  zipListsWith = f: fst: snd:
+    if fst != [] && snd != [] then
+      [ (f (head fst) (head snd)) ]
+      ++ zipLists (tail fst) (tail snd)
+    else [];
+
+  zipLists = zipListsWith (fst: snd: { inherit fst snd; });
+
 }