clean up read/show abuse

Avoid ever using read to parse a non-haskell formatted input string.

show :: Key is arguably still show abuse, but displaying Keys as filenames
is just too useful to give up.

Logs/UUIDBased.hs

@@ -50,28 +50,27 @@ showLog :: (a -> String) -> Log a -> String
 showLog shower = unlines . map showpair . M.toList
 	where
 		showpair (k, LogEntry (Date p) v) =
-			unwords [show k, shower v, tskey ++ show p]
+			unwords [fromUUID k, shower v, tskey ++ show p]
 		showpair (k, LogEntry Unknown v) =
-			unwords [show k, shower v]
+			unwords [fromUUID k, shower v]
 
 parseLog :: (String -> Maybe a) -> String -> Log a
-parseLog parser = M.fromListWith best . catMaybes . map pair . lines
+parseLog parser = M.fromListWith best . catMaybes . map parse . lines
 	where
-		pair line
+		parse line
 			| null ws = Nothing
-			| otherwise = case parser $ unwords info of
-				Nothing -> Nothing
-				Just v -> Just (read u, LogEntry c v)
+			| otherwise = parser (unwords info) >>= makepair
 			where
+				makepair v = Just (toUUID u, LogEntry ts v)
 				ws = words line
 				u = head ws
 				end = last ws
-				c
+				ts
 					| tskey `isPrefixOf` end =
 						pdate $ tail $ dropWhile (/= '=') end
 					| otherwise = Unknown
 				info
-					| c == Unknown = drop 1 ws
+					| ts == Unknown = drop 1 ws
 					| otherwise = drop 1 $ init ws
 				pdate s = case parseTime defaultTimeLocale "%s%Qs" s of
 					Nothing -> Unknown