X.P.Unicode: BS -> String to support Unicode descriptions

Switch the underlying UnicodeData data type from the current ByteString
implementation to String.  This is in order to facilitate descriptions
Unicode descriptions of the Unicode characters themselves.  We chose
String instead of Text because it does not incur an extra dependency.

Fixes: https://github.com/xmonad/xmonad-contrib/issues/733

CHANGES.md

@@ -112,6 +112,11 @@
     - Added the ability to specify alphabetic (`#A`, `#B`, and `#C`)
       [priorities] at the end of the input note.
 
+  * `XMonad.Prompt.Unicode`
+
+    - Fixed the display of non-ASCII characters in the description of Unicode
+      characters
+
   * `XMonad.Prompt`
 
     - Added `transposeChars` to interchange the characters around the

XMonad/Prompt/Unicode.hs

@@ -23,12 +23,12 @@ module XMonad.Prompt.Unicode (
  mkUnicodePrompt
  ) where
 
+import Codec.Binary.UTF8.String (decodeString)
 import qualified Data.ByteString.Char8 as BS
 import Numeric
 import System.IO
 import System.IO.Error
 import Text.Printf
-import Control.Arrow (second)
 
 import XMonad
 import XMonad.Prelude
@@ -42,7 +42,7 @@ instance XPrompt Unicode where
   commandToComplete Unicode s = s
   nextCompletion Unicode = getNextCompletion
 
-newtype UnicodeData = UnicodeData { getUnicodeData :: [(Char, BS.ByteString)] }
+newtype UnicodeData = UnicodeData { getUnicodeData :: [(Char, String)] }
   deriving (Read, Show)
 
 instance ExtensionClass UnicodeData where
@@ -79,23 +79,24 @@ populateEntries unicodeDataFilename = do
           hPutStrLn stderr "Do you have unicode-data installed?"
           return False
         Right dat -> do
-          XS.put . UnicodeData . sortOn (BS.length . snd) $ parseUnicodeData dat
+          XS.put . UnicodeData . sortOn (length . snd) $ parseUnicodeData dat
           return True
     else return True
 
-parseUnicodeData :: BS.ByteString -> [(Char, BS.ByteString)]
+parseUnicodeData :: BS.ByteString -> [(Char, String)]
 parseUnicodeData = mapMaybe parseLine . BS.lines
   where parseLine l = do
           field1 : field2 : _ <- return $ BS.split ';' l
           [(c,"")] <- return . readHex $ BS.unpack field1
-          return (chr c, field2)
+          desc <- return . decodeString $ BS.unpack field2
+          return (chr c, desc)
 
 type Predicate = String -> String -> Bool
 
-searchUnicode :: [(Char, BS.ByteString)] -> Predicate -> String -> [(Char, String)]
-searchUnicode entries p s = map (second BS.unpack) $ filter go entries
-  where w = filter (all isAscii) . filter ((> 1) . length) . words $ map toUpper s
-        go (_, d) = all (`p` BS.unpack d) w
+searchUnicode :: [(Char, String)] -> Predicate -> String -> [(Char, String)]
+searchUnicode entries p s = filter go entries
+  where w = filter ((> 1) . length) . words $ map toUpper s
+        go (_, d) = all (`p` d) w
 
 mkUnicodePrompt :: String -> [String] -> String -> XPConfig -> X ()
 mkUnicodePrompt prog args unicodeDataFilename xpCfg =
@@ -107,7 +108,7 @@ mkUnicodePrompt prog args unicodeDataFilename xpCfg =
       (unicodeCompl entries $ searchPredicate xpCfg)
       paste
   where
-    unicodeCompl :: [(Char, BS.ByteString)] -> Predicate -> String -> IO [String]
+    unicodeCompl :: [(Char, String)] -> Predicate -> String -> IO [String]
     unicodeCompl _ _ "" = return []
     unicodeCompl entries p s = do
       let m = searchUnicode entries p s