From beee6e5e1d1ab456a162de827440cd4890514a2b Mon Sep 17 00:00:00 2001
From: Sander van der Burg <s.vanderburg@tudelft.nl>
Date: Mon, 2 Aug 2010 16:10:01 +0000
Subject: [PATCH] Moved 'zip' function from nixos/lib/build-vms.nix

svn path=/nixpkgs/trunk/; revision=22882
---
 pkgs/lib/lists.nix | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/pkgs/lib/lists.nix b/pkgs/lib/lists.nix
index 9b8334a5b9df..e279d6a80f47 100644
--- a/pkgs/lib/lists.nix
+++ b/pkgs/lib/lists.nix
@@ -177,4 +177,10 @@ rec {
     let loop = l: if tail l == [] then head l else loop (tail l); in
     loop list;
 
+  # Zip two lists together.
+  zip = xs: ys:
+    if xs != [] && ys != [] then
+      [ {first = head xs; second = head ys;} ]
+      ++ zip (tail xs) (tail ys)
+    else [];
 }