Add XMonad.Util.ClickableWorkspaces module (#364)

This module enables clickable workspace tags in XMobar in a relatively unobtrusive fashion.
Inspired by https://arch-ed.dk/xmobar-clickable-workspaces

CHANGES.md

@@ -62,6 +62,12 @@
     A version of `XMonad.Prompt.Shell` that lets you use completions supplied by
     zsh.
 
+  * `XMonad.Util.ClickableWorkspaces`
+
+    Provides clickablePP, which when applied to the PP pretty-printer used by
+    `XMonad.Hooks.DynamicLog.dynamicLogWithPP`, will make the workspace tags
+    clickable in XMobar (for switching focus).
+
 ### Bug Fixes and Minor Changes
 
   * `XMonad.Util.NamedScratchpad`

XMonad/Doc/Extending.hs

@@ -1111,6 +1111,11 @@ external utilities.
 
 A non complete list with a brief description:
 
+* "XMonad.Util.ClickableWorkspaces":
+    Provides clickablePP, which when applied to the PP pretty-printer used by
+    'XMonad.Hooks.DynamicLog.dynamicLogWithPP', will make the workspace tags
+    clickable in XMobar (for switching focus).
+
 * "XMonad.Util.Cursor": configure the default cursor/pointer glyph.
 
 * "XMonad.Util.CustomKeys": configure key bindings (see

XMonad/Util/ClickableWorkspaces.hs

@@ -0,0 +1,60 @@
+-------------------------------------------------------------------------------
+-- |
+-- Module      :  XMonad.Util.ClickableWorkspaces
+-- Copyright   :  (c) Geoff deRosenroll <geoffderosenroll@gmail.com>
+-- License     :  BSD3-style (see LICENSE)
+--
+-- Maintainer  :  Geoff deRosenroll <geoffderosenroll@gmail.com>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- Provides @clickablePP@, which when applied to the PP pretty-printer used by
+-- the "XMonad.Hooks.DynamicLog" hook, will make the workspace tags clickable in
+-- XMobar (for switching focus).
+--
+-----------------------------------------------------------------------------
+
+module XMonad.Util.ClickableWorkspaces (
+  -- * Usage
+  -- $usage
+  clickablePP
+  ) where
+
+import XMonad
+import XMonad.Util.WorkspaceCompare (getWsIndex)
+import XMonad.Hooks.DynamicLog (xmobarAction, xmobarRaw, PP(..))
+
+-- $usage
+-- However you have set up your PP, apply @clickablePP@ to it, and bind the result
+-- to "XMonad.Hooks.DynamicLog"\'s dynamicLogWithPP like so:
+-- 
+-- > logHook = clickablePP xmobarPP { ... } >>= dynamicLogWithPP
+--
+-- * Requirements:
+--   * wmctrl on system (in path)
+--   * "XMonad.Hooks.EwmhDesktops" for wmctrl support (see Hackage docs for setup)
+--   * use of UnsafeStdinReader in xmobarrc (rather than StdinReader)
+
+
+clickableWrap :: Int -> String -> String
+clickableWrap i ws = xmobarAction ("wmctrl -s " ++ show i) "1" $ xmobarRaw ws
+
+-- Use index of workspace in users config to target workspace with wmctrl switch.
+getClickable :: X (WorkspaceId -> String)
+getClickable = do
+  wsIndex <- getWsIndex
+  return $ \ws -> case wsIndex ws of
+                    Just idx -> clickableWrap idx ws
+                    Nothing -> ws
+
+-- | Apply clickable wrapping to all workspace fields in given PP.
+clickablePP :: PP -> X PP
+clickablePP pp = do
+  clickable <- getClickable
+  return $
+    pp { ppCurrent         = ppCurrent pp . clickable
+       , ppVisible         = ppVisible pp . clickable
+       , ppHidden          = ppHidden pp . clickable
+       , ppHiddenNoWindows = ppHiddenNoWindows pp . clickable
+       , ppUrgent          = ppUrgent pp . clickable
+       }