From e7bc12a93265dce5704be7024e9dbac4f6ec07ae Mon Sep 17 00:00:00 2001
From: "Yury G. Kudryashov" <urkud.urkud@gmail.com>
Date: Sun, 10 Feb 2008 17:38:56 +0000
Subject: [PATCH] * Function concatMap as in Haskell.

svn path=/nixpkgs/branches/stdenv-updates/; revision=10588
---
 pkgs/lib/default.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkgs/lib/default.nix b/pkgs/lib/default.nix
index 1018d9609078..0d22070ee98d 100644
--- a/pkgs/lib/default.nix
+++ b/pkgs/lib/default.nix
@@ -52,6 +52,10 @@ rec {
     fold (x: y: x + y) "";
 
 
+  # Map and concatenate the result.
+  concatMap = f: list: concatLists (map f list);
+
+
   # Place an element between each element of a list, e.g.,
   # `intersperse "," ["a" "b" "c"]' returns ["a" "," "b" "," "c"].
   intersperse = separator: list: