XMonad confirmation when restarting

Question

I'm a Haskell beginner and I'm using xmonad. I'm trying to make it prompt me before quitting as I occasionally hit mod+q by accident. I've found two ways of doing that, but I must be doing something wrong because neither of them work for me: https://bbs.archlinux.org/viewtopic.php?id=120298 http://comments.gmane.org/gmane.comp.lang.haskell.xmonad/11699

Here's my xmonad.hs:

import XMonad
import XMonad.Config.Gnome
import XMonad.Actions.Plane
import XMonad.Util.EZConfig
import XMonad.Util.Run(spawnPipe)
import qualified Data.Map as M
import XMonad.Hooks.DynamicLog
import XMonad.Hooks.ManageDocks
import XMonad.Hooks.UrgencyHook
import System.IO(Handle, hPutStrLn)
import System.Exit
import Control.Monad
import XMonad
import XMonad.Util.EZConfig
import XMonad.Util.Dmenu
import XMonad.Util.Run

workspaces' = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "0"]

quit_confirm :: X ()
quit_confirm = do
  let m = "confirm restart"
  s <- dmenu [m]
  when (m == s) (spawn "xmonad --restart")

conf_quit = do
  response <- runProcessWithInput "dmenu" ["-p", "Quit?"] "yes\nno\n"
  when (response == "yes") (spawn "xmonad --restart")

main = do
        dzen2Pipe <- spawnPipe "dzen2 -w 1200 -xs 1 -ta l -fn '-*-terminus-*-*-*-*-16-*-*-*-*-*-*-*' -bg black -fg #d3d7cf "
        dzen2Right <- spawnPipe "~/.xmonad/status-dzen.sh"
        startupProgs <- spawnPipe "~/.xmonad/startups.sh"
        xmonad $ defaultConfig
             {
             workspaces = workspaces'
             , manageHook = manageHook' <+> manageHook defaultConfig
             , modMask = mod4Mask
             , terminal = "gnome-terminal"
     , layoutHook = layoutHook'
         , logHook = logHook' dzen2Pipe
             }
            `additionalKeysP`
               [ -- Lock Screen
                ("M-S-l",    spawn "gnome-screensaver-command -l")
                -- Sleep
                , ("M-S-;",   spawn "gnome-screensaver-command -l; pmi action suspend")
                -- wireless
                , ("M-S-C-w", spawn "~/.xmonad/wireless.sh")
                -- 1 screen reconf
                , ("M-S-C-1", spawn "~/.xmonad/1-screen.sh")
                -- 2 screen reconf
                , ("M-S-C-2", spawn "~/.xmonad/2-screen.sh")
                -- confirm for quit
                , ("M-q", conf_quit)
                ]
             `additionalKeys`
             M.toList (planeKeys mod4Mask GConf Finite)

layoutHook' = avoidStruts $ layoutHook defaultConfig

logHook' = dynamicLogWithPP . dzenPP'

dzenPP' h = defaultPP
            {
            ppOutput = hPutStrLn h
            }

manageHook' = composeAll
  [ className =? "Pidgin" --> doShift "1" ,
    className =? "Firefox" --> doShift "2" ,
    className =? "Thunderbird" --> doShift "3" ,
    className =? "OpenOffice.org 3.2" --> doShift "4",
    manageDocks ]

Thanks!

Edit: the menu is displayed, but spawn process doesn't seem to work.

Answer 1

The answers others gave missed that dmenu seems to add an extra whitespace to the end of the string it returns. You just need to do the following and it works for me:

confirm :: String -> X () -> X ()
confirm m f = do
  result <- dmenu [m]
  when (init result == m) f

And then, as @mariop suggested use either

confirm "Restart" $ spawn "xmonad --recompile && xmonad --restart"

or

confirm "Exit" $ io (exitWith ExitSuccess)

Answer 2

Change the key binding to

("M-q", confirm "Confirm restart?" $ restart "xmonad" True)

And add a generic confirmation action that uses dmenu

confirm :: String -> X () -> X ()
confirm msg f = do
    a <- dmenu [msg,"y","n"]
    when (a=="y") f

Answer 3

I wrote the following module, which doesn't require dmenu to be installed:

-----------------------------------------------------------------------------
-- |
-- Module      :  XMonad.Prompt
-- Copyright   :  (C) 2015 Antoine Beaupré
-- License     :  BSD3
--
-- Maintainer  :  Antoine Beaupré <anarcat@debian.org>
-- Stability   :  unstable
-- Portability :  unportable
--
-- A module for setting up simple confirmation prompts for keybindings.
--
-----------------------------------------------------------------------------
module XMonad.Prompt.ConfirmPrompt (confirmPrompt
                                    -- * Usage
                                    -- $usage
                                    , module XMonad.Prompt
                                    -- * Use case: confirming exit
                                    -- $tip
                                    , EnterPrompt
                                    ) where

import XMonad (X)
import XMonad.Prompt (XPConfig, XPrompt, showXPrompt, mkXPrompt, mkComplFunFromList)

{- $usage

This module makes it easy to add a confirmation prompt for specific
actions. Instead of just running the action, a simple confirmation
prompt will be created using 'XMonad.Prompt' primitives. The action
will then run normally if the user confirms.
-}

{- $tip
This should be used something like this:

> ...
> , ((modm , xK_l), confirmPrompt defaultXPConfig "exit" $ io (exitWith ExitSuccess))
> ...
-}

{- | Customized 'XPrompt' prompt that will ask to confirm the given string -}
data EnterPrompt = EnterPrompt String
instance XPrompt EnterPrompt where
    showXPrompt (EnterPrompt n) = "Confirm " ++ n ++ " (esc/ENTER)"

{- | Prompt the user to confirm a given action. We offer no completion
     and simply ask to confirm (ENTER) or cancel (ESCAPE). The actual key
     handling is done by mkXPrompt.-}
confirmPrompt :: XPConfig -> String -> X() -> X()
confirmPrompt config app func = mkXPrompt (EnterPrompt app) config (mkComplFunFromList []) $ const func

Install this in a ~/.xmonad/lib/XMonad/Prompt directory and enjoy!

(I submitted this to the XMonad mailing list and I'm waiting for feedback...)

Answer 4

You say you want a quit confirm but your code does a restart confirm. If this is restart that you want, I tested and quit_confirm works.

What you most likely miss is the recompilation of xmonad to see your new configuration. Try this:

quit_confirm :: X ()
quit_confirm = do
  let m = "confirm restart"
  s <- dmenu [m]
  when (m == s) (spawn "xmonad recompile && xmonad --restart")