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Diffstat (limited to 'doc')
-rw-r--r-- | doc/plugins.org | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/doc/plugins.org b/doc/plugins.org index 48999c2..a1fa4df 100644 --- a/doc/plugins.org +++ b/doc/plugins.org @@ -1436,6 +1436,50 @@ choice. hPutStr writeHandle "Hello World" #+end_src +** Software Transactional Memory + +When invoking xmobar from other Haskell code it can be easier and +more performant to use shared memory. The following plugins leverage +=Control.Concurrent.STM= to realize these gains for xmobar. + +*** =QueueReader (TQueue a) (a -> String) String= + + - Display data from a Haskell =TQueue a=. + + - This plugin is only useful if you are running xmobar from another + haskell program like xmonad. + + - You should make an =IO= safe =TQueue a= with =Control.Concurrent.STM.newTQueueIO=. + Write to it from the user code with =writeTQueue=, and read with =readTQueue=. + A common use is to overwite =ppOutput= from =XMonad.Hooks.DynamicLog= as shown + below. + + #+begin_src haskell + main :: IO () + main = do + q <- STM.newTQueueIO @String + bar <- forkIO $ xmobar myConf + { commands = Run (QueueReader q id "XMonadLog") : commands myConf } + xmonad $ def { logHook = logWorkspacesToQueue q } + + logWorkspacesToQueue :: STM.TQueue String -> X () + logWorkspacesToQueue q = + dynamicLogWithPP def { ppOutput = STM.atomically . STM.writeTQueue q } + where + -- Manage the PrettyPrinting configuration here. + ppLayout' :: String -> String + ppLayout' "Spacing Tall" = xpm "layout-spacing-tall" + ppLayout' "Spacing Mirror Tall" = xpm "layout-spacing-mirror" + ppLayout' "Spacing Full" = xpm "layout-full" + ppLayout' x = x + + icon :: String -> String + icon path = "<icon=" ++ path ++ "/>" + + xpm :: String -> String + xpm = icon . (++ ".xpm") + #+end_src + * Executing External Commands In order to execute an external command you can either write the command |