scripts/xmonadpropread: Document and support custom props

XMonad/Hooks/DynamicLog.hs

@@ -154,15 +154,16 @@ import XMonad.Hooks.ManageDocks
 -- >        }
 --
 -- If you don't have an @.xmobarrc@, create it; the @XMonadLog@ plugin is not
--- part of the default xmobar configuration and you status bar will not show
+-- part of the default xmobar configuration and your status bar will not show
 -- otherwise!
 --
 -- Because 'statusBarProp' lets you define your own executable, you can also
 -- give it a different status bar entirely; you only need to make sure that the
 -- status bar supports reading a property string from the root window, or use
--- some kind of wrapper that reads the property and pipes it into the bar.
+-- a wrapper that reads the property and pipes it into the bar (e.g.
+-- @xmonadpropread | dzen2@, see @scripts/xmonadpropread.hs@).
 --
--- If you don't want to read from the default property, you can specify your own
+-- If you don't want to use the default property, you can specify your own
 -- with the 'statusBarPropTo' function.
 --
 -- If your status bar does not support property-based logging, you may also try

scripts/xmonadpropread.hs

@@ -1,20 +1,38 @@
 -- Copyright Spencer Janssen <spencerjanssen@gmail.com>
 -- BSD3 (see LICENSE)
 --
--- Experimental, will add proper documentation later (famous last words)
+-- Reads from an X property on the root window and writes to standard output.
+--
+-- May be used together with XMonad.Hooks.DynamicLog.xmonadPropLog and a
+-- status bar that doesn't support reading from properties itself, such as
+-- dzen.
+--
+-- Usage:
+--
+--  $ xmonadpropread | dzen2
+--
+-- or
+--
+--  $ xmonadpropread _XMONAD_LOG_CUSTOM | dzen2
 
 import Control.Monad
 import Graphics.X11
 import Graphics.X11.Xlib.Extras
 import Codec.Binary.UTF8.String as UTF8
 import Foreign.C (CChar)
+import System.Environment
 import System.IO
 
+main :: IO ()
 main = do
     hSetBuffering stdout LineBuffering
 
+    atom <- flip fmap getArgs $ \args -> case args of
+        [a] -> a
+        _   -> "_XMONAD_LOG"
+
     d <- openDisplay ""
-    xlog <- internAtom d "_XMONAD_LOG" False
+    xlog <- internAtom d atom False
 
     root  <- rootWindow d (defaultScreen d)
     selectInput d root propertyChangeMask
@@ -28,7 +46,5 @@ main = do
                 maybe (return ()) (putStrLn . decodeCChar) mwp
             _ -> return ()
 
-    return ()
-
 decodeCChar :: [CChar] -> String
 decodeCChar = UTF8.decode . map fromIntegral