ENH use optparse for xmobar

bin/xmobar.hs

@@ -13,12 +13,12 @@ module Main (main) where
 
 import Data.Internal.DBus
 import Data.Internal.Dependency
+import Options.Applicative
 import RIO hiding (hFlush)
 import qualified RIO.ByteString.Lazy as BL
 import RIO.List
 import RIO.Process
 import qualified RIO.Text as T
-import UnliftIO.Environment
 import XMonad.Core hiding (config)
 import XMonad.Internal.Command.Desktop
 import XMonad.Internal.Command.Power
@@ -40,19 +40,42 @@ import Xmobar.Plugins.Screensaver
 import Xmobar.Plugins.VPN
 
 main :: IO ()
-main = getArgs >>= parse
+main = parse >>= xio
 
-parse :: [String] -> IO ()
-parse [] = run
-parse ["--deps"] = withCache printDeps
-parse ["--test"] = withCache $ withDBus_ evalConfig
-parse _ = usage
+parse :: IO XOpts
+parse = execParser opts
+  where
+    parseOpts = parseDeps <|> parseTest <|> pure XRun
+    opts =
+      info (parseOpts <**> helper) $
+        fullDesc <> header "xmobar: the best taskbar ever"
 
-run :: IO ()
+data XOpts = XDeps | XTest | XRun
+
+parseDeps :: Parser XOpts
+parseDeps =
+  flag'
+    XDeps
+    (long "deps" <> short 'd' <> help "print dependencies")
+
+parseTest :: Parser XOpts
+parseTest =
+  flag'
+    XTest
+    (long "test" <> short 't' <> help "test dependencies without running")
+
+xio :: XOpts -> IO ()
+xio o = withCache $
+  case o of
+    XDeps -> printDeps
+    XTest -> withDBus_ evalConfig
+    XRun -> run
+
+run :: FIO ()
 run = do
   -- IDK why this is needed, I thought this was default
-  hSetBuffering stdout LineBuffering
-  withCache $ withDBus_ $ \db -> do
+  liftIO $ hSetBuffering stdout LineBuffering
+  withDBus_ $ \db -> do
     c <- evalConfig db
     liftIO $ xmobar c
 
@@ -73,15 +96,6 @@ printDeps = withDBus_ $ \db ->
           concatMap dumpFeature $
             allFeatures db
 
-usage :: IO ()
-usage =
-  putStrLn $
-    intercalate
-      "\n"
-      [ "xmobar: run greatest taskbar"
-      , "xmobar --deps: print dependencies"
-      ]
-
 --------------------------------------------------------------------------------
 -- toplevel configuration