From ed4e0ed06f9110a90d62bd85e7701a2b48a5e5f9 Mon Sep 17 00:00:00 2001
From: John Millikin <jmillikin@gmail.com>
Date: Thu, 17 Feb 2011 08:23:29 -0800
Subject: [PATCH] Add ``Ord`` instances for ``Instruction``, ``Name``, and
 ``Doctype``.

---
 Data/XML/Types.hs | 31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/Data/XML/Types.hs b/Data/XML/Types.hs
index f46ee79..432f8bc 100644
--- a/Data/XML/Types.hs
+++ b/Data/XML/Types.hs
@@ -62,6 +62,7 @@ import Control.Monad ((>=>))
 import Data.Text.Lazy (Text)
 import qualified Data.Text.Lazy as T
 import Data.String (IsString, fromString)
+import Data.Function (on)
 
 data Document = Document
 	{ documentPrologue :: Prologue
@@ -81,7 +82,7 @@ data Instruction = Instruction
 	{ instructionTarget :: Text
 	, instructionData :: Text
 	}
-	deriving (Show, Eq)
+	deriving (Show, Eq, Ord)
 
 data Miscellaneous
 	= MiscInstruction Instruction
@@ -113,11 +114,6 @@ data Content
 	| ContentEntity Text
 	deriving (Show, Eq)
 
--- | The 'Eq' instance for 'Name' ignores prefixes.
---
--- The 'IsString' instance for 'Name' allows entry using Clark notation;
--- see <http://www.jclark.com/xml/xmlns.htm> and
--- <http://infohost.nmt.edu/tcc/help/pubs/pylxml/etree-QName.html>
 data Name = Name
 	{ nameLocalName :: Text
 	, nameNamespace :: Maybe Text
@@ -125,13 +121,20 @@ data Name = Name
 	}
 	deriving (Show)
 
--- Ignore prefixes when comparing names
+-- | Ignores prefixes
 instance Eq Name where
-	x == y = and
-		[ nameLocalName x == nameLocalName y
-		, nameNamespace x == nameNamespace y
-		]
+	(==) = (==) `on` (\x -> (nameNamespace x, nameLocalName x))
+
+-- | Ignores prefixes
+--
+-- Since 0.1.3
+instance Ord Name where
+	compare = compare `on` (\x -> (nameNamespace x, nameLocalName x))
 
+-- | Supports Clark notation; see <http://www.jclark.com/xml/xmlns.htm> and
+-- <http://infohost.nmt.edu/tcc/help/pubs/pylxml/etree-QName.html>
+--
+-- Since 0.1.2
 instance IsString Name where
 	fromString "" = Name T.empty Nothing Nothing
 	fromString full@('{':rest) = case break (== '}') rest of
@@ -155,10 +158,14 @@ data Doctype = Doctype
 	}
 	deriving (Show, Eq)
 
+-- | Since 0.1.3
+instance Ord Doctype where
+	compare = compare `on` (\x -> (doctypeName x, doctypeExternalID x))
+
 data ExternalID
 	= SystemID Text
 	| PublicID Text Text
-	deriving (Show, Eq)
+	deriving (Show, Eq, Ord)
 
 data InternalSubset = InternalSubset
 	-- TODO
-- 
2.45.2