remove read of the heads

and one tail

Removed head from Utility.PartialPrelude in order to avoid the build
warning with recent ghc versions as well.

Utility/DataUnits.hs

@@ -180,16 +180,16 @@ compareSizes units abbrev old new
 
 {- Parses strings like "10 kilobytes" or "0.5tb". -}
 readSize :: [Unit] -> String -> Maybe ByteSize
-readSize units input
-	| null parsednum || null parsedunit = Nothing
-	| otherwise = Just $ round $ number * fromIntegral multiplier
+readSize units input = case parsednum of
+	[] -> Nothing
+	((number, rest):_) ->
+		let unitname = takeWhile isAlpha $ dropWhile isSpace rest
+		in case lookupUnit units unitname of
+			[] -> Nothing
+			(multiplier:_) -> 
+				Just $ round $ number * fromIntegral multiplier
   where
-	(number, rest) = head parsednum
-	multiplier = head parsedunit
-	unitname = takeWhile isAlpha $ dropWhile isSpace rest
-
 	parsednum = reads input :: [(Double, String)]
-	parsedunit = lookupUnit units unitname
 
 	lookupUnit _ [] = [1] -- no unit given, assume bytes
 	lookupUnit [] _ = []

Utility/Misc.hs

@@ -52,9 +52,8 @@ readFileStrict = readFile >=> \s -> length s `seq` return s
 separate :: (a -> Bool) -> [a] -> ([a], [a])
 separate c l = unbreak $ break c l
   where
-	unbreak r@(a, b)
-		| null b = r
-		| otherwise = (a, tail b)
+	unbreak (a, (_:b)) = (a, b)
+	unbreak r = r
 
 separate' :: (Word8 -> Bool) -> S.ByteString -> (S.ByteString, S.ByteString)
 separate' c l = unbreak $ S.break c l

Utility/PartialPrelude.hs

@@ -9,8 +9,6 @@
 
 module Utility.PartialPrelude (
 	Utility.PartialPrelude.read,
-	Utility.PartialPrelude.head,
-	Utility.PartialPrelude.tail,
 	Utility.PartialPrelude.init,
 	Utility.PartialPrelude.last,
 	Utility.PartialPrelude.readish,
@@ -27,16 +25,6 @@ import qualified Data.Maybe
 read :: Read a => String -> a
 read = Prelude.read
 
-{- head is a partial function; head [] is an error
- - Instead, use: take 1 or headMaybe -}
-head :: [a] -> a
-head = Prelude.head
-
-{- tail is also partial
- - Instead, use: drop 1 -}
-tail :: [a] -> [a]
-tail = Prelude.tail
-
 {- init too
  - Instead, use: beginning -}
 init :: [a] -> [a]

Utility/Tor.hs

@@ -80,7 +80,7 @@ addHiddenService appname uid ident = do
 		((p, _s):_) -> waithiddenservice 1 p
 		_ -> do
 			highports <- R.getStdRandom mkhighports
-			let newport = Prelude.head $
+			let newport = fromMaybe (error "internal") $ headMaybe $
 				filter (`notElem` map fst portssocks) highports
 			torrc <- findTorrc
 			writeFile torrc $ unlines $