From 071f8f23b010afab6ab916c480035753c82fc962 Mon Sep 17 00:00:00 2001
From: Michael Orlitzky <michael@orlitzky.com>
Date: Mon, 29 Dec 2014 16:34:59 -0500
Subject: [PATCH] Use Generics.to_tuple in TSN.XML.Heartbeat.

---
 src/TSN/XML/Heartbeat.hs | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/TSN/XML/Heartbeat.hs b/src/TSN/XML/Heartbeat.hs
index 8fafba1..b44f930 100644
--- a/src/TSN/XML/Heartbeat.hs
+++ b/src/TSN/XML/Heartbeat.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 
 -- | Handle documents defined by Heartbeat.dtd.
@@ -12,6 +13,7 @@ where
 -- System imports.
 import Data.Time.Clock ( UTCTime )
 import Data.Tuple.Curry ( uncurryN )
+import qualified GHC.Generics as GHC ( Generic )
 import Test.Tasty ( TestTree, testGroup )
 import Test.Tasty.HUnit ( (@?=), testCase )
 import Text.XML.HXT.Core (
@@ -25,6 +27,7 @@ import Text.XML.HXT.Core (
   xpWrap )
 
 -- Local imports.
+import Generics ( Generic(..), to_tuple )
 import TSN.DbImport ( ImportResult(..) )
 import TSN.Picklers ( xp_time_stamp )
 import Xml ( pickle_unpickle, unpickleable )
@@ -39,11 +42,15 @@ dtd = "Heartbeat.dtd"
 --   Heartbeat message.
 --
 data Message =
-  Message {
-    xml_file_id :: Int,
-    heading :: String,
-    time_stamp :: UTCTime }
-  deriving (Eq, Show)
+  Message
+    Int     -- xml_file_id
+    String  -- heading
+    UTCTime -- time_stamp
+  deriving (Eq, GHC.Generic, Show)
+
+-- | For 'Generics.to_tuple'.
+--
+instance Generic Message
 
 
 -- | A (un)pickler that turns a Heartbeat XML file into a 'Message'
@@ -58,9 +65,6 @@ pickle_message =
              (xpElem "time_stamp" xp_time_stamp)
   where
     from_tuple = uncurryN Message
-    to_tuple m = (xml_file_id m,
-                  heading m,
-                  time_stamp m)
 
 
 -- | Verify (and report) the received heartbeat. We return
-- 
2.43.2