From e0be32f6760e26aab599a09ee2b4d71b4497f7e8 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Fri, 5 Oct 2012 13:45:27 -0400
Subject: [PATCH] =?UTF-8?q?Add=20a=20function=20=E2=80=98getVersion?=
 =?UTF-8?q?=E2=80=99=20to=20get=20the=20version=20of=20a=20derivation?=
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---
 pkgs/lib/strings.nix | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/pkgs/lib/strings.nix b/pkgs/lib/strings.nix
index 4bd7a5bebde..19d1738182f 100644
--- a/pkgs/lib/strings.nix
+++ b/pkgs/lib/strings.nix
@@ -155,6 +155,12 @@ rec {
   # Return true iff string v1 denotes a version older than v2.
   versionOlder = v1: v2: builtins.compareVersions v2 v1 == 1;
 
+
+  # Get the version of the specified derivation, as specified in its
+  # ‘name’ attribute.
+  getVersion = drv: (builtins.parseDrvName drv.name).version;
+
+
   # Extract name with version from URL. Ask for separator which is 
   # supposed to start extension
   nameFromURL = url: sep: let