Add X.H.WorkspaceHistory

Ignore-this: c9e7ce33a944facc27481dde52c7cc80

darcs-hash:20130109023307-7d114-b7e9156b6305334b707b63d04099e08a19bcc058.gz

1 files changed, 74 insertions, 0 deletions

diff --git a/XMonad/Hooks/WorkspaceHistory.hs b/XMonad/Hooks/WorkspaceHistory.hs
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+++ b/XMonad/Hooks/WorkspaceHistory.hs
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+{-# LANGUAGE DeriveDataTypeable #-}
+
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  XMonad.Hooks.WorkspaceHistory
+-- Copyright   :  (c) 2013 Dmitri Iouchtchenko
+-- License     :  BSD3-style (see LICENSE)
+--
+-- Maintainer  :  Dmitri Iouchtchenko <johnnyspoon@gmail.com>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- Keeps track of workspace viewing order.
+--
+-----------------------------------------------------------------------------
+
+module XMonad.Hooks.WorkspaceHistory
+    ( -- * Usage
+      -- $usage
+
+      -- * Hooking
+      workspaceHistoryHook
+
+      -- * Querying
+    , workspaceHistory
+
+    ) where
+
+import XMonad
+import XMonad.StackSet (currentTag)
+import qualified XMonad.Util.ExtensibleState as XS
+
+-- $usage
+-- To record the order in which you view workspaces, you can use this
+-- module with the following in your @~\/.xmonad\/xmonad.hs@:
+--
+-- > import XMonad.Hooks.WorkspaceHistory (workspaceHistoryHook)
+--
+-- Then add the hook to your 'logHook':
+--
+-- >  main = xmonad $ defaultConfig
+-- >      { ...
+-- >      , logHook = ... >> workspaceHistoryHook >> ...
+-- >      , ...
+-- >      }
+--
+-- To make use of the collected data, a query function is provided.
+
+data WorkspaceHistory =
+    WorkspaceHistory { history :: [WorkspaceId] -- ^ Workspaces in reverse-chronological order.
+                     }
+    deriving (Typeable, Read, Show)
+
+instance ExtensionClass WorkspaceHistory where
+    initialValue = WorkspaceHistory []
+    extensionType = PersistentExtension
+
+-- | A 'logHook' that keeps track of the order in which workspaces have
+-- been viewed.
+workspaceHistoryHook :: X ()
+workspaceHistoryHook = gets (currentTag . windowset) >>= (XS.modify . makeFirst)
+
+-- | A list of workspace tags in the order they have been viewed, with the
+-- most recent first. No duplicates are present, but not all workspaces are
+-- guaranteed to appear, and there may be workspaces that no longer exist.
+workspaceHistory :: X [WorkspaceId]
+workspaceHistory = XS.gets history
+
+
+-- | Cons the 'WorkspaceId' onto the 'WorkspaceHistory' if it is not
+-- already there, or move it to the front if it is.
+makeFirst :: WorkspaceId -> WorkspaceHistory -> WorkspaceHistory
+makeFirst w v = let (xs, ys) = break (w ==) $ history v
+                in v { history = w : (xs ++ drop 1 ys) }