fix perl refugee code

Backend.hs

@@ -40,21 +40,21 @@ import qualified TypeInternals as Internals
 list :: Annex [Backend]
 list = do
 	l <- Annex.backends -- list is cached here
-	if (0 < length l)
+	if (not $ null l)
 		then return l
 		else do
 			all <- Annex.supportedBackends
 			g <- Annex.gitRepo
 			let l = parseBackendList all $ Git.configGet g "annex.backends" ""
 			backendflag <- Annex.flagGet "backend"
-			let l' = if (0 < length backendflag)
+			let l' = if (not $ null backendflag)
 				then (lookupBackendName all backendflag):l
 				else l
 			Annex.backendsChange $ l'
 			return l'
 	where
 		parseBackendList all s = 
-			if (length s == 0)
+			if (null s)
 				then all
 				else map (lookupBackendName all) $ words s
 

Backend/File.hs

@@ -62,7 +62,7 @@ checkKeyFile k = do
 copyKeyFile :: Key -> FilePath -> Annex (Bool)
 copyKeyFile key file = do
 	remotes <- Remotes.withKey key
-	if (0 == length remotes)
+	if (null remotes)
 		then do
 			showNote "not available"
 			showLocations key
@@ -142,7 +142,7 @@ checkRemoveKey key = do
 				"Could only verify the existence of " ++
 				(show have) ++ " out of " ++ (show need) ++ 
 				" necessary copies"
-			if (0 /= length bad) then showTriedRemotes bad else return ()
+			if (not $ null bad) then showTriedRemotes bad else return ()
 			showLocations key
 			hint
 			return False
@@ -156,9 +156,9 @@ showLocations key = do
 	uuids <- liftIO $ keyLocations g key
 	let uuidsf = filter (\v -> v /= u) uuids
 	ppuuids <- prettyPrintUUIDs uuidsf
-	if (0 < length uuidsf)
-		then showLongNote $ "Try making some of these repositories available:\n" ++ ppuuids
-		else showLongNote $ "No other repository is known to contain the file."
+	if (null uuidsf)
+		then showLongNote $ "No other repository is known to contain the file."
+		else showLongNote $ "Try making some of these repositories available:\n" ++ ppuuids
 		
 showTriedRemotes remotes =
 	showLongNote $ "I was unable to access these remotes: " ++

Commands.hs

@@ -117,9 +117,9 @@ findWanted Description params _ = do
 parseCmd :: [String] -> AnnexState -> IO ([Annex ()], [Annex ()])
 parseCmd argv state = do
 	(flags, params) <- getopt
-	case (length params) of
-		0 -> error usage
-		_ -> case (lookupCmd (params !! 0)) of
+	if (null params)
+		then error usage
+		else case (lookupCmd (params !! 0)) of
 			[] -> error usage
 			[Command _ action want _] -> do
 				f <- findWanted want (drop 1 params)
@@ -258,7 +258,7 @@ fixCmd file = inBackend file $ \(key, backend) -> do
 {- Stores description for the repository. -}
 initCmd :: String -> Annex ()
 initCmd description = do
-	if (0 == length description)
+	if (null description)
 		then error $ 
 			"please specify a description of this repository\n" ++
 			usage
@@ -275,7 +275,7 @@ initCmd description = do
 fromKeyCmd :: FilePath -> Annex ()
 fromKeyCmd file = do
 	keyname <- Annex.flagGet "key"
-	if (0 == length keyname)
+	if (null keyname)
 		then error "please specify the key with --key"
 		else return ()
 	backends <- Backend.list

Remotes.hs

@@ -49,11 +49,11 @@ withKey key = do
 			let cheap = filter (not . Git.repoIsUrl) allremotes
 			let expensive = filter Git.repoIsUrl allremotes
 			doexpensive <- filterM cachedUUID expensive
-			if (0 < length doexpensive)
+			if (not $ null doexpensive)
 				then showNote $ "getting UUIDs for " ++ (list doexpensive) ++ "..."
 				else return ()
 			let todo = cheap ++ doexpensive
-			if (0 < length todo)
+			if (not $ null todo)
 				then do
 					e <- mapM tryGitConfigRead todo
 					Annex.flagChange "remotesread" $ FlagBool True
@@ -62,7 +62,7 @@ withKey key = do
 	where
 		cachedUUID r = do
 			u <- getUUID r
-			return $ 0 == length u 
+			return $ null u 
 
 {- Cost Ordered list of remotes. -}
 remotesByCost :: Annex [Git.Repo]
@@ -90,7 +90,7 @@ reposByCost l = do
 repoCost :: Git.Repo -> Annex Int
 repoCost r = do
 	g <- Annex.gitRepo
-	if ((length $ config g r) > 0)
+	if (not $ null $ config g r)
 		then return $ read $ config g r
 		else if (Git.repoIsUrl r)
 			then return 200

UUID.hs

@@ -103,7 +103,7 @@ prettyPrintUUIDs uuids = do
 	return $ unwords $ map (\u -> "\t"++(prettify m u)++"\n") uuids
 	where
 		prettify m u =
-			if (0 < (length $ findlog m u))
+			if (not $ null $ findlog m u)
 				then u ++ "  -- " ++ (findlog m u)
 				else u
 		findlog m u = M.findWithDefault "" u m

Utility.hs

@@ -45,7 +45,7 @@ hGetContentsStrict h  = hGetContents h >>= \s -> length s `seq` return s
 {- Returns the parent directory of a path. Parent of / is "" -}
 parentDir :: String -> String
 parentDir dir =
-	if length dirs > 0
+	if (not $ null dirs)
 	then slash ++ (join s $ take ((length dirs) - 1) dirs)
 	else ""
 		where
@@ -81,7 +81,7 @@ relPathCwdToDir dir = do
  -}
 relPathDirToDir :: FilePath -> FilePath -> FilePath
 relPathDirToDir from to = 
-	if (0 < length path)
+	if (not $ null path)
 		then addTrailingPathSeparator path
 		else ""
 	where