ui: on posix, support ctrl-z to suspend the program

hledger-ui/Hledger/UI/AccountsScreen.hs

@@ -40,6 +40,7 @@ import Hledger.UI.Editor
 import Hledger.UI.RegisterScreen
 import Hledger.UI.ErrorScreen
 
+
 accountsScreen :: Screen
 accountsScreen = AccountsScreen{
    sInit   = asInit
@@ -277,6 +278,7 @@ asHandle ui0@UIState{
         VtyEvent (EvKey KEnter []) -> continue $ regenerateScreens j d $ setFilter s $ closeMinibuffer ui
                             where s = chomp $ unlines $ map strip $ getEditContents ed
         VtyEvent (EvKey (KChar 'l') [MCtrl]) -> redraw ui
+        VtyEvent (EvKey (KChar 'z') [MCtrl]) -> suspendAndRedraw ui
         VtyEvent ev        -> do ed' <- handleEditorEvent ev ed
                                  continue $ ui{aMode=Minibuffer ed'}
         AppEvent _        -> continue ui
@@ -287,6 +289,7 @@ asHandle ui0@UIState{
       case ev of
         VtyEvent (EvKey (KChar 'q') []) -> halt ui
         VtyEvent (EvKey (KChar 'l') [MCtrl]) -> redraw ui
+        VtyEvent (EvKey (KChar 'z') [MCtrl]) -> suspendAndRedraw ui
         _                    -> helpHandle ui ev
 
     Normal ->
@@ -340,6 +343,7 @@ asHandle ui0@UIState{
         VtyEvent (EvKey k           []) | k `elem` [KBS, KDel] -> (continue $ regenerateScreens j d $ resetFilter ui)
         VtyEvent e | e `elem` moveLeftEvents -> continue $ popScreen ui
         VtyEvent (EvKey (KChar 'l') [MCtrl]) -> scrollSelectionToMiddle _asList >> redraw ui
+        VtyEvent (EvKey (KChar 'z') [MCtrl]) -> suspendAndRedraw ui
 
         -- enter register screen for selected account (if there is one), 
         -- centering its selected transaction if possible

hledger-ui/Hledger/UI/ErrorScreen.hs

@@ -86,6 +86,7 @@ esHandle ui@UIState{aScreen=ErrorScreen{..}
       case ev of
         VtyEvent (EvKey (KChar 'q') []) -> halt ui
         VtyEvent (EvKey (KChar 'l') [MCtrl]) -> redraw ui
+        VtyEvent (EvKey (KChar 'z') [MCtrl]) -> suspendAndRedraw ui
         _                    -> helpHandle ui ev
 
     _ -> do
@@ -107,6 +108,7 @@ esHandle ui@UIState{aScreen=ErrorScreen{..}
 --             Right j' -> continue $ regenerateScreens j' d $ popScreen ui  -- return to previous screen, and reload it
         VtyEvent (EvKey (KChar 'I') []) -> continue $ uiCheckBalanceAssertions d (popScreen $ toggleIgnoreBalanceAssertions ui)
         VtyEvent (EvKey (KChar 'l') [MCtrl]) -> redraw ui
+        VtyEvent (EvKey (KChar 'z') [MCtrl]) -> suspendAndRedraw ui
         _ -> continue ui
 
 esHandle _ _ = error "event handler called with wrong screen type, should not happen"

hledger-ui/Hledger/UI/RegisterScreen.hs

@@ -282,6 +282,7 @@ rsHandle ui@UIState{
         VtyEvent (EvKey KEnter []) -> continue $ regenerateScreens j d $ setFilter s $ closeMinibuffer ui
                             where s = chomp $ unlines $ map strip $ getEditContents ed
         VtyEvent (EvKey (KChar 'l') [MCtrl]) -> redraw ui
+        VtyEvent (EvKey (KChar 'z') [MCtrl]) -> suspendAndRedraw ui
         VtyEvent ev              -> do ed' <- handleEditorEvent ev ed
                                        continue $ ui{aMode=Minibuffer ed'}
         AppEvent _        -> continue ui
@@ -292,6 +293,7 @@ rsHandle ui@UIState{
       case ev of
         VtyEvent (EvKey (KChar 'q') []) -> halt ui
         VtyEvent (EvKey (KChar 'l') [MCtrl]) -> redraw ui
+        VtyEvent (EvKey (KChar 'z') [MCtrl]) -> suspendAndRedraw ui
         _                    -> helpHandle ui ev
 
     Normal ->
@@ -336,6 +338,7 @@ rsHandle ui@UIState{
         VtyEvent (EvKey k           []) | k `elem` [KBS, KDel] -> (continue $ regenerateScreens j d $ resetFilter ui)
         VtyEvent e | e `elem` moveLeftEvents  -> continue $ popScreen ui
         VtyEvent (EvKey (KChar 'l') [MCtrl]) -> scrollSelectionToMiddle rsList >> redraw ui
+        VtyEvent (EvKey (KChar 'z') [MCtrl]) -> suspendAndRedraw ui
 
         -- enter transaction screen for selected transaction
         VtyEvent e | e `elem` moveRightEvents -> do

hledger-ui/Hledger/UI/TransactionScreen.hs

@@ -120,6 +120,7 @@ tsHandle ui@UIState{aScreen=s@TransactionScreen{tsTransaction=(i,t)
       case ev of
         VtyEvent (EvKey (KChar 'q') []) -> halt ui
         VtyEvent (EvKey (KChar 'l') [MCtrl]) -> redraw ui
+        VtyEvent (EvKey (KChar 'z') [MCtrl]) -> suspendAndRedraw ui
         _                    -> helpHandle ui ev
 
     _ -> do
@@ -180,6 +181,7 @@ tsHandle ui@UIState{aScreen=s@TransactionScreen{tsTransaction=(i,t)
             ui'@UIState{aScreen=scr} = popScreen ui
             ui'' = ui'{aScreen=rsSelect (fromIntegral i) scr}
         VtyEvent (EvKey (KChar 'l') [MCtrl]) -> redraw ui
+        VtyEvent (EvKey (KChar 'z') [MCtrl]) -> suspendAndRedraw ui
         _ -> continue ui
 
 tsHandle _ _ = error "event handler called with wrong screen type, should not happen"

hledger-ui/Hledger/UI/UIUtils.hs

@@ -21,6 +21,8 @@ module Hledger.UI.UIUtils (
   ,renderToggle
   ,replaceHiddenAccountsNameWith
   ,scrollSelectionToMiddle
+  ,suspend
+  ,suspendAndRedraw
   ,redraw
 )
 where
@@ -50,6 +52,35 @@ import Hledger.Cli.DocFiles
 import Hledger.UI.UITypes
 import Hledger.UI.UIState
 
+-- | On posix platforms, suspend the program using the system STOP signal
+-- (as control-z usually does in bash). On windows, does nothing.
+#ifdef mingw32_HOST_OS
+suspend :: IO ()
+suspend = return ()
+#else
+import System.Posix.Signals
+suspend :: IO ()
+suspend = raiseSignal sigSTOP 
+#endif
+
+-- | On posix platforms, suspend the program using the system STOP
+-- signal, returning to the original shell prompt
+-- (TODO: and restore the original terminal attributes).
+-- When the program is resumed, redraw the screen and continue.
+-- On windows, just redraws the screen.
+suspendAndRedraw :: s -> EventM a (Next s)
+suspendAndRedraw ui = do
+  -- reset terminal attributes using vty ?
+  -- Vty{outputIface=output} <- getVtyHandle
+  -- r <- displayBounds output
+  -- DisplayContext{writeDefaultAttr=_reset} <- liftIO $ (mkDisplayContext output) output r
+  -- runWrite (reset True) _someptr
+
+  -- suspend..
+  liftIO suspend
+
+  -- ..and resume
+  redraw ui
 
 -- | Tell vty to redraw the whole screen, and continue.
 redraw :: s -> EventM a (Next s)
@@ -74,7 +105,7 @@ helpDialog _copts =
     render $
       withDefAttr "help" $
       renderDialog (dialog (Just "Help (?/LEFT/ESC to close)") Nothing (c^.availWidthL)) $ -- (Just (0,[("ok",())]))
-      padAll 1 $
+      padTop (Pad 1) $ padLeft (Pad 1) $ padRight (Pad 1) $
         vBox [
            hBox [
               padRight (Pad 1) $
@@ -120,8 +151,9 @@ helpDialog _copts =
                   ,renderKey ("A   ", "add transaction (hledger-iadd)")
                   ,renderKey ("E   ", "open editor")
                   ,renderKey ("I   ", "toggle balance assertions")
-                  ,renderKey ("C-l ", "redraw & recenter")
                   ,renderKey ("g   ", "reload data")
+                  ,renderKey ("C-l ", "redraw & recenter")
+                  ,renderKey ("C-z ", "suspend")
                   ,renderKey ("q   ", "quit")
                 ]
              ]

hledger-ui/hledger-ui.cabal

@@ -4,7 +4,7 @@ cabal-version: 1.12
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 9e7f4d999a8b69e7adb4b03f99c96b7ae47113f1b11fe7ddb289e352b2632e7c
+-- hash: cb5960060c369ce0540af1659e44ad678d26cbc9dca2e8481fe8657bc8fc13ab
 
 name:           hledger-ui
 version:        1.12.99
@@ -95,6 +95,7 @@ executable hledger-ui
   else
     build-depends:
         brick >=0.12
+      , unix
       , vty >=5.5
   if flag(threaded)
     ghc-options: -threaded

hledger-ui/package.yaml

@@ -82,6 +82,7 @@ when:
    else:
      dependencies:
        - brick >=0.12
+       - unix
        - vty >=5.5
 
 executables: