Added Eq instance for DynEncoding

This envolves adding the requirement, that every Encoding must also be an instance of Eq and Typeable to go into DynEncoding.

darcs-hash:20090225035150-a4fee-c7d902e28313929ee9ffe0c6a6b60d8ff4704ae9

Data/Encoding.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleContexts,ExistentialQuantification #-}
+{-# LANGUAGE FlexibleContexts #-}
 module Data.Encoding
     (module Data.Encoding.Exception
     ,module Data.Encoding.ByteSource
@@ -77,14 +77,6 @@ import Data.Encoding.JISX0208
 import Data.Char
 import Text.Regex
 
-data DynEncoding = forall enc. Encoding enc => DynEncoding enc
-
-instance Encoding DynEncoding where
-    decodeChar (DynEncoding e) = decodeChar e
-    encodeChar (DynEncoding e) = encodeChar e
-    decode (DynEncoding e) = decode e
-    encode (DynEncoding e) = encode e
-
 recode :: (Encoding enc1,Encoding enc2,ByteSource m,ByteSink m) => enc1 -> enc2 -> m ()
 recode e1 e2 = untilM_ sourceEmpty (decodeChar e1 >>= encodeChar e2)
 

Data/Encoding/Base.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE ExistentialQuantification #-}
 module Data.Encoding.Base where
 
 import Data.Encoding.Exception
@@ -9,6 +10,7 @@ import Data.Array as Array
 import Data.Map as Map hiding ((!))
 import Data.Word
 import Data.Char
+import Data.Typeable
 
 class Encoding enc where
     decodeChar :: ByteSource m => enc -> m Char
@@ -17,6 +19,21 @@ class Encoding enc where
     decode e = untilM sourceEmpty (decodeChar e)
     encode :: ByteSink m => enc -> String -> m ()
     encode e = mapM_ (encodeChar e)
+    encodeable :: enc -> Char -> Bool
+
+data DynEncoding = forall enc. (Encoding enc,Eq enc,Typeable enc) => DynEncoding enc
+
+instance Encoding DynEncoding where
+    decodeChar (DynEncoding e) = decodeChar e
+    encodeChar (DynEncoding e) = encodeChar e
+    decode (DynEncoding e) = decode e
+    encode (DynEncoding e) = encode e
+    encodeable (DynEncoding e) = encodeable e
+
+instance Eq DynEncoding where
+    (DynEncoding e1) == (DynEncoding e2) = case cast e2 of
+                                             Nothing -> False
+                                             Just e2' -> e1==e2'
 
 untilM :: Monad m => m Bool -> m a -> m [a]
 untilM check act = do

Data/Encoding/CP1250.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.CP1250 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/CP1251.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.CP1251 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/CP1252.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.CP1252 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/CP1253.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.CP1253 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/CP1254.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.CP1254 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/CP1255.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.CP1255 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/CP1256.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.CP1256 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/CP1257.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.CP1257 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/CP1258.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.CP1258 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/Helper/Template.hs

@@ -7,6 +7,7 @@ import Data.Char
 import Data.Maybe (mapMaybe)
 import Data.Map as Map (fromList,lookup)
 import Data.Array
+import Data.Typeable
 import Language.Haskell.TH
 
 makeISOInstance :: String -> FilePath -> Q [Dec]
@@ -23,9 +24,9 @@ makeJISInstance name file = do
   arr <- decodingArray2 (fillTranslations (0x21,0x21) (0x7E,0x7E) trans)
   return $ encodingInstance 'encodeWithMap2 'decodeWithArray2 name mp arr
 
-encodingInstance :: Name -> Name -> String -> Exp -> Exp -> [Dec]
+encodingInstance :: Name -> Name -> Name -> String -> Exp -> Exp -> [Dec]
-encodingInstance enc dec name mp arr
+encodingInstance enc dec able name mp arr
-    = [ DataD [] rname [] [NormalC rname []] [''Show]
+    = [ DataD [] rname [] [NormalC rname []] [''Show,''Eq,''Typeable]
       , InstanceD [] (AppT (ConT ''Encoding) (ConT rname))
                       [FunD 'encodeChar
                        [Clause [WildP] (NormalB $ AppE (VarE enc) (VarE rmp))

Data/Encoding/ISO88591.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE DeriveDataTypeable #-}
 module Data.Encoding.ISO88591 where
 
 import Control.Throws
@@ -6,8 +7,9 @@ import Data.Encoding.Exception
 import Data.Encoding.ByteSource
 import Data.Encoding.ByteSink
 import Data.Char (ord,chr)
+import Data.Typeable
 
-data ISO88591 = ISO88591 deriving (Show)
+data ISO88591 = ISO88591 deriving (Show,Eq,Typeable)
 
 instance Encoding ISO88591 where
     encodeChar _ c

Data/Encoding/ISO885910.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO885910 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO885911.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO885911 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO885913.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO885913 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO885914.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO885914 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO885915.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO885915 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO885916.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO885916 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO88592.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO88592 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO88593.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO88593 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO88594.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO88594 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO88595.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO88595 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO88596.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO88596 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO88597.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO88597 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO88598.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO88598 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/ISO88599.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.ISO88599 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/JISX0201.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.JISX0201 where
 
 import Data.Encoding.Helper.Template (makeISOInstance)

Data/Encoding/JISX0208.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskell,DeriveDataTypeable #-}
 module Data.Encoding.JISX0208 where
 
 import Data.Encoding.Helper.Template (makeJISInstance)