tv xmonad: resume by reading state from file

tv/2configs/xserver/default.nix

@@ -119,12 +119,7 @@ let
     settle ${pkgs.xorg.xhost}/bin/xhost +LOCAL:
     settle ${pkgs.xorg.xrdb}/bin/xrdb -merge ${import ./Xresources.nix args}
     settle ${pkgs.xorg.xsetroot}/bin/xsetroot -solid '#1c1c1c'
-    if test -e "$XMONAD_STATE"; then
-      IFS=''$'\n'
-      exec ${xmonad-pkg}/bin/xmonad --resume $(< "$XMONAD_STATE")
-    else
-      exec ${xmonad-pkg}/bin/xmonad
-    fi
+    exec ${xmonad-pkg}/bin/xmonad
   '';
 
   xmonad-stop = pkgs.writeScriptBin "xmonad-stop" ''

tv/2configs/xserver/xmonad/Main.hs

@@ -1,4 +1,5 @@
 {-# LANGUAGE DeriveDataTypeable #-} -- for XS
+{-# LANGUAGE FlexibleContexts #-} -- for xmonad'
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 
@@ -8,7 +9,7 @@ module Main where
 import Control.Exception
 import Text.Read (readEither)
 import XMonad
-import System.Environment (getArgs, getEnv, getEnvironment)
+import System.Environment (getArgs, withArgs, getEnv, getEnvironment)
 import System.Posix.Process (executeFile)
 import XMonad.Prompt (defaultXPConfig)
 import XMonad.Actions.DynamicWorkspaces ( addWorkspacePrompt, renameWorkspace
@@ -56,7 +57,7 @@ main = getArgs >>= \case
 mainNoArgs :: IO ()
 mainNoArgs = do
     workspaces0 <- getWorkspaces0
-    xmonad
+    xmonad'
         -- $ withUrgencyHookC dzenUrgencyHook { args = ["-bg", "magenta", "-fg", "magenta", "-h", "2"], duration = 500000 }
         --                   urgencyConfig { remindWhen = Every 1 }
         -- $ withUrgencyHook borderUrgencyHook "magenta"
@@ -82,6 +83,17 @@ mainNoArgs = do
         (FixedColumn 1 20 80 10 ||| Full)
 
 
+xmonad' :: (LayoutClass l Window, Read (l Window)) => XConfig l -> IO ()
+xmonad' conf = do
+    path <- getEnv "XMONAD_STATE"
+    try (readFile path) >>= \case
+        Right content -> do
+            putStrLn ("resuming from " ++ path)
+            withArgs ("--resume" : lines content) (xmonad conf)
+        Left e -> do
+            putStrLn (displaySomeException e)
+            xmonad conf
+
 getWorkspaces0 :: IO [String]
 getWorkspaces0 =
     try (getEnv "XMONAD_WORKSPACES0_FILE") >>= \case