add W.shiftMaster, fix float/tile-reordering bug

XMonad/Config.hs

@@ -226,12 +226,12 @@ mouseBindings :: XConfig Layout -> M.Map (KeyMask, Button) (Window -> X ())
 mouseBindings (XConfig {XMonad.modMask = modMask}) = M.fromList $
     -- mod-button1 %! Set the window to floating mode and move by dragging
     [ ((modMask, button1), (\w -> focus w >> mouseMoveWindow w
-                                          >> windows W.swapMaster))
+                                          >> windows W.shiftMaster))
     -- mod-button2 %! Raise the window to the top of the stack
-    , ((modMask, button2), (\w -> focus w >> windows W.swapMaster))
+    , ((modMask, button2), (\w -> focus w >> windows W.shiftMaster))
     -- mod-button3 %! Set the window to floating mode and resize by dragging
     , ((modMask, button3), (\w -> focus w >> mouseResizeWindow w
-                                          >> windows W.swapMaster))
+                                          >> windows W.shiftMaster))
     -- you may also bind events to the mouse scroll wheel (button4 and button5)
     ]
 

XMonad/StackSet.hs

@@ -42,7 +42,7 @@ module XMonad.StackSet (
         insertUp, delete, delete', filter,
         -- * Setting the master window
         -- $settingMW
-        swapUp, swapDown, swapMaster, modify, modify', float, sink, -- needed by users
+        swapUp, swapDown, swapMaster, shiftMaster, modify, modify', float, sink, -- needed by users
         -- * Composite operations
         -- $composite
         shift, shiftWin,
@@ -508,6 +508,15 @@ swapMaster = modify' $ \c -> case c of
 
 -- natural! keep focus, move current to the top, move top to current.
 
+-- | /O(s)/. Set the master window to the focused window.
+-- The other windows are kept in order and shifted down on the stack, as if you
+-- just hit mod-shift-k a bunch of times.
+-- Focus stays with the item moved.
+shiftMaster :: StackSet i l a s sd -> StackSet i l a s sd
+shiftMaster = modify' $ \c -> case c of
+    Stack _ [] _ -> c     -- already master.
+    Stack t ls rs -> Stack t [] (reverse ls ++ rs)
+
 -- | /O(s)/. Set focus to the master window.
 focusMaster :: StackSet i l a s sd -> StackSet i l a s sd
 focusMaster = modify' $ \c -> case c of

man/xmonad.hs

@@ -157,13 +157,15 @@ myKeys conf@(XConfig {XMonad.modMask = modMask}) = M.fromList $
 myMouseBindings (XConfig {XMonad.modMask = modMask}) = M.fromList $
 
     -- mod-button1, Set the window to floating mode and move by dragging
-    [ ((modMask, button1), (\w -> focus w >> mouseMoveWindow w))
+    [ ((modMask, button1), (\w -> focus w >> mouseMoveWindow w
+                                          >> windows W.shiftMaster))
 
     -- mod-button2, Raise the window to the top of the stack
-    , ((modMask, button2), (\w -> focus w >> windows W.swapMaster))
+    , ((modMask, button2), (\w -> focus w >> windows W.shiftMaster))
 
     -- mod-button3, Set the window to floating mode and resize by dragging
-    , ((modMask, button3), (\w -> focus w >> mouseResizeWindow w))
+    , ((modMask, button3), (\w -> focus w >> mouseResizeWindow w
+                                          >> windows W.shiftMaster))
 
     -- you may also bind events to the mouse scroll wheel (button4 and button5)
     ]

tests/Properties.hs

@@ -528,6 +528,18 @@ prop_shift_reversible i (x :: T) =
         y = swapMaster x
         n = tag (workspace $ current y)
 
+------------------------------------------------------------------------
+-- shiftMaster
+
+-- focus/local/idempotent same as swapMaster:
+prop_shift_master_focus (x :: T) = peek x == (peek $ shiftMaster x)
+prop_shift_master_local (x :: T) = hidden_spaces x == hidden_spaces (shiftMaster x)
+prop_shift_master_idempotent (x :: T) = shiftMaster (shiftMaster x) == shiftMaster x
+-- ordering is constant modulo the focused window:
+prop_shift_master_ordering (x :: T) = case peek x of
+    Nothing -> True
+    Just m  -> L.delete m (index x) == L.delete m (index $ shiftMaster x)
+
 -- ---------------------------------------------------------------------
 -- shiftWin
 
@@ -933,6 +945,11 @@ main = do
         ,("swapUp is local"   , mytest prop_swap_left_local)
         ,("swapDown is local"  , mytest prop_swap_right_local)
 
+        ,("shiftMaster id on focus", mytest prop_shift_master_focus)
+        ,("shiftMaster is local", mytest prop_shift_master_local)
+        ,("shiftMaster is idempotent", mytest prop_shift_master_idempotent)
+        ,("shiftMaster preserves ordering", mytest prop_shift_master_ordering)
+
         ,("shift: invariant"    , mytest prop_shift_I)
         ,("shift is reversible" , mytest prop_shift_reversible)
         ,("shiftWin: invariant" , mytest prop_shift_win_I)