From 9f59fb9377351d28f54174259f27ae2c23dc9dfd Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Wed, 22 Jul 2009 14:43:39 +0000
Subject: [PATCH] * findFirst is used by the LaTeX function.  Forgot to commit.

svn path=/nixpkgs/trunk/; revision=16438
---
 pkgs/lib/lists.nix | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/pkgs/lib/lists.nix b/pkgs/lib/lists.nix
index 8ac93476a53..012b95ad061 100644
--- a/pkgs/lib/lists.nix
+++ b/pkgs/lib/lists.nix
@@ -65,6 +65,13 @@ rec {
        else head found;
 
 
+  # Find the first element in the list matching the specified
+  # predicate or returns `default' if no such element exists.
+  findFirst = pred: default: list:
+    let found = filter pred list;
+    in if found == [] then default else head found;
+       
+
   # Return true iff function `pred' returns true for at least element
   # of `list'.
   any = pred: list: