X.H.DynamicLog: Add shorten' and shortenLeft' (customizable end)

XMonad/Hooks/DynamicLog.hs

@@ -43,7 +43,7 @@ module XMonad.Hooks.DynamicLog (
     dzenPP, xmobarPP, sjanssenPP, byorgeyPP,
 
     -- * Formatting utilities
-    wrap, pad, trim, shorten, shortenLeft,
+    wrap, pad, trim, shorten, shorten', shortenLeft, shortenLeft',
     xmobarColor, xmobarAction, xmobarBorder,
     xmobarRaw, xmobarStrip, xmobarStripTags,
     dzenColor, dzenEscape, dzenStrip, filterOutWsPP,
@@ -386,18 +386,22 @@ trim = f . f
 
 -- | Limit a string to a certain length, adding "..." if truncated.
 shorten :: Int -> String -> String
-shorten n xs | length xs < n = xs
-             | otherwise     = take (n - length end) xs ++ end
- where
-    end = "..."
+shorten = shorten' "..."
+
+-- | Limit a string to a certain length, adding @end@ if truncated.
+shorten' :: String -> Int -> String -> String
+shorten' end n xs | length xs < n = xs
+                  | otherwise     = take (n - length end) xs ++ end
 
 -- | Like 'shorten', but truncate from the left instead of right.
 shortenLeft :: Int -> String -> String
-shortenLeft n xs | l < n     = xs
-                 | otherwise = end ++ (drop (l - n + length end) xs)
- where
-    end = "..."
-    l = length xs
+shortenLeft = shortenLeft' "..."
+
+-- | Like 'shorten'', but truncate from the left instead of right.
+shortenLeft' :: String -> Int -> String -> String
+shortenLeft' end n xs | l < n     = xs
+                      | otherwise = end ++ (drop (l - n + length end) xs)
+ where l = length xs
 
 -- | Output a list of strings, ignoring empty ones and separating the
 --   rest with the given separator.