Added encodeable function

darcs-hash:20090225040044-a4fee-67753f6d651b18d5bd3a28340ea8f5d7ea7eb90d

Data/Encoding/ASCII.hs

@@ -14,4 +14,5 @@ instance Encoding ASCII where
       w <- fetchWord8
       return $ chr $ fromIntegral w
     encodeChar _ c = do
-      pushWord8 $ fromIntegral $ ord c
+      pushWord8 $ fromIntegral $ ord c
+    encodeable _ c = c < '\128'

Data/Encoding/Base.hs

@@ -61,6 +61,9 @@ encodeWithMap2 mp c = case Map.lookup c mp of
                           pushWord8 w1
                           pushWord8 w2
 
+encodeableWithMap :: Map Char a -> Char -> Bool
+encodeableWithMap = flip Map.member
+
 decodeWithArray :: ByteSource m => Array Word8 (Maybe Char) -> m Char
 decodeWithArray arr = do
   w <- fetchWord8

Data/Encoding/BootString.hs

@@ -182,3 +182,4 @@ instance Encoding BootString where
                                 Nothing -> punyDecode base nbase
                                 Just ww -> throwException (IllegalCharacter ww)
 	Nothing -> punyDecode [] wrds
+    encodeable bs c = True -- XXX: hm, really?

Data/Encoding/GB18030.hs

@@ -127,6 +127,7 @@ instance Encoding GB18030 where
 	                  2 -> pushWord8 w2
 	                  3 -> pushWord8 w2 >> pushWord8 w3
 	                  4 -> pushWord8 w2 >> pushWord8 w3 >> pushWord8 w4
+    encodeable _ c = c <= '\x10FFFF'
 
 linear :: Word8 -> Word8 -> Word8 -> Word8 -> Int
 linear w1 w2 w3 w4

Data/Encoding/Helper/Template.hs

@@ -15,14 +15,14 @@ makeISOInstance name file = do
   trans <- runIO (readTranslation file)
   mp <- encodingMap (validTranslations trans)
   arr <- decodingArray (fillTranslations 0 255 trans)
-  return $ encodingInstance 'encodeWithMap 'decodeWithArray name mp arr
+  return $ encodingInstance 'encodeWithMap 'decodeWithArray 'encodeableWithMap name mp arr
 
 makeJISInstance :: String -> FilePath -> Q [Dec]
 makeJISInstance name file = do
   trans <- runIO (readJISTranslation file)
   mp <- encodingMap2 (validTranslations trans)
   arr <- decodingArray2 (fillTranslations (0x21,0x21) (0x7E,0x7E) trans)
-  return $ encodingInstance 'encodeWithMap2 'decodeWithArray2 name mp arr
+  return $ encodingInstance 'encodeWithMap2 'decodeWithArray2 'encodeableWithMap name mp arr
 
 encodingInstance :: Name -> Name -> Name -> String -> Exp -> Exp -> [Dec]
 encodingInstance enc dec able name mp arr
@@ -36,6 +36,10 @@ encodingInstance enc dec able name mp arr
                        [Clause [WildP] (NormalB $ AppE (VarE dec) (VarE rarr))
                         [ValD (VarP rarr) (NormalB arr) []]
                        ]
+                      ,FunD 'encodeable
+                       [Clause [WildP] (NormalB $ AppE (VarE able) (VarE rmp))
+                        [ValD (VarP rmp) (NormalB mp) []]
+                       ]
                       ]
       ]
     where

Data/Encoding/ISO88591.hs

@@ -17,4 +17,5 @@ instance Encoding ISO88591 where
                | otherwise = pushWord8 (fromIntegral $ ord c)
     decodeChar _ = do
       w <- fetchWord8
-      return (chr $ fromIntegral w)
+      return (chr $ fromIntegral w)
+    encodeable _ c = c <= '\255'

Data/Encoding/KOI8R.hs

@@ -56,4 +56,5 @@ instance Encoding KOI8R where
 	| ch < '\128' = pushWord8 $ fromIntegral $ ord ch
 	| otherwise   = case lookup ch koi8rMap of
 		Just w -> pushWord8 w
-		Nothing -> throwException (HasNoRepresentation ch)
+		Nothing -> throwException (HasNoRepresentation ch)
+    encodeable _ c = member c koi8rMap

Data/Encoding/KOI8U.hs

@@ -56,4 +56,5 @@ instance Encoding KOI8U where
 	| ch < '\128' = pushWord8 $ fromIntegral $ ord ch
 	| otherwise   = case lookup ch koi8uMap of
 		Just w  -> pushWord8 w
-		Nothing -> throwException (HasNoRepresentation ch)
+		Nothing -> throwException (HasNoRepresentation ch)
+    encodeable _ c = member c koi8uMap

Data/Encoding/UTF16.hs

@@ -79,3 +79,4 @@ instance Encoding UTF16 where
                  return (c:cs)
         Right bom -> decode bom
     decode enc = untilM sourceEmpty (decodeChar enc)
+    encodeable _ c = c <= '\x10FFFF'

Data/Encoding/UTF32.hs

@@ -44,3 +44,4 @@ instance Encoding UTF32 where
           rest <- untilM sourceEmpty (decodeChar UTF32)
           return ((chr $ fromIntegral ch):rest)
     decode enc = untilM sourceEmpty (decodeChar enc)
+    encodeable _ _ = True

Data/Encoding/UTF8.hs

@@ -38,6 +38,7 @@ instance Encoding UTF8 where
                where
                  n = ord c
                  p8 = pushWord8.fromIntegral
+    encodeable _ c = c <= '\x10FFFF'
     decodeChar UTF8 = do
       w1 <- fetchWord8
       case () of