From 2bf1915b692ac6ba1078367e2f490ff44b37b791 Mon Sep 17 00:00:00 2001
From: David Roundy <droundy@darcs.net>
Date: Fri, 14 Sep 2007 23:59:59 +0200
Subject: move Layout stuff into class (hokey first cut).

darcs-hash:20070914215959-72aca-3feae03a6560a70908ad37d28f47c8d47321008e.gz
---
 XMonad.hs | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

(limited to 'XMonad.hs')

diff --git a/XMonad.hs b/XMonad.hs
index 64232f6..97f4ee1 100644
--- a/XMonad.hs
+++ b/XMonad.hs
@@ -15,7 +15,7 @@
 -----------------------------------------------------------------------------
 
 module XMonad (
-    X, WindowSet, WorkspaceId, ScreenId(..), ScreenDetail(..), XState(..), XConf(..), Layout(..),
+    X, WindowSet, WorkspaceId, ScreenId(..), ScreenDetail(..), XState(..), XConf(..), Layout(..), OldLayout(..), SomeLayout(..),
     Typeable, Message, SomeMessage(..), fromMessage, runLayout,
     runX, catchX, io, catchIO, withDisplay, withWindowSet, isRoot, getAtom, spawn, restart, trace, whenJust, whenX,
     atom_WM_STATE, atom_WM_PROTOCOLS, atom_WM_DELETE_WINDOW
@@ -43,7 +43,7 @@ data XState = XState
     { windowset    :: !WindowSet           -- ^ workspace list
     , mapped       :: !(S.Set Window)      -- ^ the Set of mapped windows
     , waitingUnmap :: !(M.Map Window Int)  -- ^ the number of expected UnmapEvents
-    , layouts      :: !(M.Map WorkspaceId (Layout Window, [Layout Window]))
+    , layouts      :: !(M.Map WorkspaceId (SomeLayout Window, [SomeLayout Window]))
                        -- ^ mapping of workspaces to descriptions of their layouts
     , dragging     :: !(Maybe (Position -> Position -> X (), X ())) }
 data XConf = XConf
@@ -131,10 +131,27 @@ atom_WM_STATE           = getAtom "WM_STATE"
 -- that message and the screen is not refreshed.  Otherwise, 'modifyLayout'
 -- returns an updated 'Layout' and the screen is refreshed.
 --
-data Layout a = Layout { doLayout     :: Rectangle -> Stack a -> X ([(a, Rectangle)], Maybe (Layout a))
-                       , modifyLayout :: SomeMessage -> X (Maybe (Layout a)) }
+data OldLayout a =
+    OldLayout { doLayout'     :: Rectangle -> Stack a -> X ([(a, Rectangle)], Maybe (OldLayout a))
+              , modifyLayout' :: SomeMessage -> X (Maybe (OldLayout a)) }
 
-runLayout :: Layout a -> Rectangle -> StackOrNot a -> X ([(a, Rectangle)], Maybe (Layout a))
+data SomeLayout a = forall l. Layout l a => SomeLayout (l a)
+
+class Layout layout a where
+    doLayout :: layout a -> Rectangle -> Stack a -> X ([(a, Rectangle)], Maybe (layout a))
+    modifyLayout :: layout a -> SomeMessage -> X (Maybe (layout a))
+
+instance Layout OldLayout a where
+    doLayout = doLayout'
+    modifyLayout = modifyLayout'
+
+instance Layout SomeLayout a where
+    doLayout (SomeLayout l) r s = do (ars, ml') <- doLayout l r s
+                                     return (ars, SomeLayout `fmap` ml' )
+    modifyLayout (SomeLayout l) m = do ml' <- modifyLayout l m
+                                       return (SomeLayout `fmap` ml')
+
+runLayout :: Layout l a => l a -> Rectangle -> StackOrNot a -> X ([(a, Rectangle)], Maybe (l a))
 runLayout l r = maybe (return ([], Nothing)) (doLayout l r)
 
 -- | Based on ideas in /An Extensible Dynamically-Typed Hierarchy of Exceptions/,
-- 
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