fetching a specific revision from a subversion repository

svn path=/nixpkgs/trunk/; revision=287

pkgs/fetchsvn/fetchsvn.fix

@@ -0,0 +1,9 @@
+Function(["name","url","rev"],
+  Package(
+    [ ("name",  Var("name"))
+    , ("build", Relative("fetchsvn/fetchsvn.sh"))
+    , ("url",   Var("url"))
+    , ("rev",   Var("rev"))
+    ]
+  )
+)

pkgs/fetchsvn/fetchsvn.sh

@@ -0,0 +1,6 @@
+#! /bin/sh
+
+echo "exporting svn repository $url (at rev $rev) into $out..."
+
+svn export -r $rev $url $out || exit 1
+