@@ -1,43 +1,114 @@
1−{-|
2−Module: Reflex.Vty.Widget
3−Description: Basic set of widgets and building blocks for reflex-vty applications
4−-}
5−{-# Language UndecidableInstances #-}
6−
7−module Reflex.Vty.Widget where
1+{-# LANGUAGE FlexibleContexts #-}
2+{-# LANGUAGE FlexibleInstances #-}
3+{-# LANGUAGE FunctionalDependencies #-}
4+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
5+{-# LANGUAGE LambdaCase #-}
6+{-# LANGUAGE MultiParamTypeClasses #-}
7+{-# LANGUAGE OverloadedStrings #-}
8+{-# LANGUAGE RankNTypes #-}
9+{-# LANGUAGE RecursiveDo #-}
10+{-# LANGUAGE TypeFamilies #-}
11+module Reflex.Vty.Widget
12+ ( VtyWidgetCtx(..)
13+ , VtyWidget(..)
14+ , VtyWidgetOut(..)
15+ , runVtyWidget
16+ , mainWidget
17+ , mainWidgetWithHandle
18+ , HasDisplaySize(..)
19+ , displayWidth
20+ , displayHeight
21+ , HasFocus(..)
22+ , HasVtyInput(..)
23+ , Region(..)
24+ , regionSize
25+ , regionBlankImage
26+ , Drag (..)
27+ , drag
28+ , mouseDown
29+ , pane
30+ , modifyImages
31+ , tellImages
32+ , tellShutdown
33+ , wrapText
34+ , splitV
35+ , splitVDrag
36+ , fractionSz
37+ , box
38+ , text
39+ , display
40+ , hyphenBoxStyle
41+ , singleBoxStyle
42+ , roundedBoxStyle
43+ , thickBoxStyle
44+ , doubleBoxStyle
45+ , fill
46+ , hRule
47+ , TextInputConfig(..)
48+ , textInput
49+ , multilineTextInput
50+ , def
51+ ) where
852
953import Control.Applicative (liftA2)
1054import Control.Monad.Fix (MonadFix)
11−import Control.Monad.IO.Class (MonadIO)
12−import Control.Monad.Morph
13−import Control.Monad.NodeId
14−import Control.Monad.Reader (ReaderT, ask, local, runReaderT)
15−import Control.Monad.Ref
16−import Control.Monad.Trans (MonadTrans, lift)
17−import Data.Set (Set)
18−import qualified Data.Set as Set
19−import Graphics.Vty (Image)
55+import Control.Monad.Trans (lift)
56+import Control.Monad.Trans.Reader (ReaderT, runReaderT, asks, ask)
57+import Control.Monad.Trans.Writer (WriterT, runWriterT, censor, tell)
58+import Data.Char
59+import Data.Default
60+import Data.Maybe (fromMaybe)
61+import Data.Text (Text)
62+import qualified Data.Text as T
63+import Graphics.Vty (Image, Attr)
2064import qualified Graphics.Vty as V
2165import Reflex
22−import Reflex.Class ()
23−import Reflex.Host.Class (MonadReflexCreateTrigger)
66+
2467import Reflex.Vty.Host
2568
26−-- * Running a vty application
27−
28−-- | Sets up the top-level context for a vty widget and runs it with that context
29−mainWidgetWithHandle
30− :: V.Vty
31− -> (forall t m.
32− ( MonadVtyApp t m
33− , HasImageWriter t m
34− , MonadNodeId m
35− , HasDisplayRegion t m
36− , HasFocusReader t m
37− , HasInput t m
38− , HasTheme t m
39− ) => m (Event t ()))
40− -> IO ()
69+-- | The context within which a 'VtyWidget' runs
70+data VtyWidgetCtx t = VtyWidgetCtx
71+ { _vtyWidgetCtx_size :: Dynamic t (Int,Int)
72+ -- ^ The width and height of the region allocated to the widget.
73+ , _vtyWidgetCtx_focus :: Dynamic t Bool
74+ -- ^ Whether the widget should behave as if it has focus for keyboard input.
75+ , _vtyWidgetCtx_input :: Event t VtyEvent
76+ -- ^ User input events that the widget's parent chooses to share. These will generally
77+ -- be filtered for relevance:
78+ -- * Keyboard inputs are restricted to focused widgets
79+ -- * Mouse inputs are restricted to the region in which the widget resides and are
80+ -- translated into its internal coordinates.
81+ }
82+
83+-- | The output of a 'VtyWidget'
84+data VtyWidgetOut t = VtyWidgetOut
85+ { _vtyWidgetOut_images :: Behavior t [Image]
86+ -- ^ The visual output of the 'VtyWidget'
87+ , _vtyWidgetOut_shutdown :: Event t ()
88+ }
89+
90+instance Reflex t => Semigroup (VtyWidgetOut t) where
91+ wo <> wo' = VtyWidgetOut
92+ { _vtyWidgetOut_images = _vtyWidgetOut_images wo <> _vtyWidgetOut_images wo'
93+ , _vtyWidgetOut_shutdown = _vtyWidgetOut_shutdown wo <> _vtyWidgetOut_shutdown wo'
94+ }
95+
96+instance (Reflex t) => Monoid (VtyWidgetOut t) where
97+ mempty = VtyWidgetOut mempty mempty
98+ mappend wo wo' = wo <> wo'
99+
100+newtype VtyWidget t m a = VtyWidget { unVtyWidget :: WriterT (VtyWidgetOut t) (ReaderT (VtyWidgetCtx t) m) a }
101+ deriving (Functor, Applicative, Monad, MonadSample t, MonadHold t, MonadFix)
102+
103+-- | Runs a 'VtyWidget' with a given context
104+runVtyWidget :: (Reflex t)
105+ => VtyWidgetCtx t
106+ -> VtyWidget t m a
107+ -> m (a, VtyWidgetOut t)
108+runVtyWidget ctx w = runReaderT (runWriterT (unVtyWidget w)) ctx
109+
110+-- | Sets up the top-level context for a 'VtyWidget' and runs it with that context
111+mainWidgetWithHandle :: V.Vty -> (forall t m. MonadVtyApp t m => VtyWidget t m ()) -> IO ()
41112mainWidgetWithHandle vty child =
42113 runVtyAppWithHandle vty $ \dr0 inp -> do
43114 size <- holdDyn dr0 $ fforMaybe inp $ \case
@@ -46,180 +117,59 @@ mainWidgetWithHandle vty child =
46117 let inp' = fforMaybe inp $ \case
47118 V.EvResize {} -> Nothing
48119 x -> Just x
49− (shutdown, images) <- runThemeReader (constant V.defAttr) $
50− runFocusReader (pure True) $
51− runDisplayRegion (fmap (\(w, h) -> Region 0 0 w h) size) $
52− runImageWriter $
53− runNodeIdT $
54− runInput inp' $ do
55− tellImages . ffor (current size) $ \(w, h) -> [V.charFill V.defAttr ' ' w h]
56− child
120+ let ctx = VtyWidgetCtx
121+ { _vtyWidgetCtx_size = size
122+ , _vtyWidgetCtx_input = inp'
123+ , _vtyWidgetCtx_focus = constDyn True
124+ }
125+ ((), wo) <- runVtyWidget ctx child
57126 return $ VtyResult
58− { _vtyResult_picture = fmap (V.picForLayers . reverse) images
59− , _vtyResult_shutdown = shutdown
127+ { _vtyResult_picture = fmap (V.picForLayers . reverse) (_vtyWidgetOut_images wo)
128+ , _vtyResult_shutdown = _vtyWidgetOut_shutdown wo
60129 }
61130
62−-- | The output of a vty widget
63−data VtyWidgetOut t = VtyWidgetOut
64− { _vtyWidgetOut_shutdown :: Event t ()
65− }
66−
67131-- | Like 'mainWidgetWithHandle', but uses a default vty configuration
68−mainWidget
69− :: (forall t m.
70− ( MonadVtyApp t m
71− , HasImageWriter t m
72− , MonadNodeId m
73− , HasDisplayRegion t m
74− , HasFocusReader t m
75− , HasTheme t m
76− , HasInput t m
77− ) => m (Event t ()))
78− -> IO ()
132+mainWidget :: (forall t m. MonadVtyApp t m => VtyWidget t m ()) -> IO ()
79133mainWidget child = do
80134 vty <- getDefaultVty
81135 mainWidgetWithHandle vty child
82136
83−-- * Input Events
137+class (Reflex t, Monad m) => HasDisplaySize t m | m -> t where
138+ displaySize :: m (Dynamic t (Int, Int))
139+
140+instance (Reflex t, Monad m) => HasDisplaySize t (VtyWidget t m) where
141+ displaySize = VtyWidget . lift $ asks _vtyWidgetCtx_size
84142
85−-- | A class for things that can receive vty events as input
86−class HasInput t m | m -> t where
143+displayWidth :: HasDisplaySize t m => m (Dynamic t Int)
144+displayWidth = fmap fst <$> displaySize
145+
146+displayHeight :: HasDisplaySize t m => m (Dynamic t Int)
147+displayHeight = fmap snd <$> displaySize
148+
149+class HasVtyInput t m | m -> t where
87150 input :: m (Event t VtyEvent)
88− default input :: (f m' ~ m, Monad m', MonadTrans f, HasInput t m') => m (Event t VtyEvent)
89− input = lift input
90− -- | User input events that the widget's parent chooses to share. These will generally
91− -- be filtered for relevance.
92− localInput :: (Event t VtyEvent -> Event t VtyEvent) -> m a -> m a
93− default localInput :: (f m' ~ m, Monad m', MFunctor f, HasInput t m') => (Event t VtyEvent -> Event t VtyEvent) -> m a -> m a
94− localInput f = hoist (localInput f)
95−
96−instance (Reflex t, Monad m) => HasInput t (Input t m) where
97− input = Input ask
98− localInput f (Input m) = Input $ local f m
99−
100−-- | A widget that can receive input events. See 'Graphics.Vty.Event'
101−newtype Input t m a = Input
102− { unInput :: ReaderT (Event t VtyEvent) m a
103− } deriving
104− ( Functor
105− , Applicative
106− , Monad
107− , MonadSample t
108− , MonadHold t
109− , MonadFix
110− , MonadIO
111− , MonadRef
112− )
113−
114−instance (Adjustable t m, MonadHold t m, Reflex t) => Adjustable t (Input t m) where
115− runWithReplace a0 a' = Input $ runWithReplace (unInput a0) $ fmap unInput a'
116− traverseIntMapWithKeyWithAdjust f dm0 dm' = Input $
117− traverseIntMapWithKeyWithAdjust (\k v -> unInput (f k v)) dm0 dm'
118− traverseDMapWithKeyWithAdjust f dm0 dm' = Input $ do
119− traverseDMapWithKeyWithAdjust (\k v -> unInput (f k v)) dm0 dm'
120− traverseDMapWithKeyWithAdjustWithMove f dm0 dm' = Input $ do
121− traverseDMapWithKeyWithAdjustWithMove (\k v -> unInput (f k v)) dm0 dm'
122−
123−deriving instance MonadReflexCreateTrigger t m => MonadReflexCreateTrigger t (Input t m)
124−deriving instance NotReady t m => NotReady t (Input t m)
125−deriving instance PerformEvent t m => PerformEvent t (Input t m)
126−deriving instance PostBuild t m => PostBuild t (Input t m)
127−deriving instance TriggerEvent t m => TriggerEvent t (Input t m)
128−instance HasImageWriter t m => HasImageWriter t (Input t m)
129−instance HasDisplayRegion t m => HasDisplayRegion t (Input t m)
130−instance HasFocusReader t m => HasFocusReader t (Input t m)
131−
132−instance MonadTrans (Input t) where
133− lift f = Input $ lift f
134−
135−instance MFunctor (Input t) where
136− hoist f = Input . hoist f . unInput
137−
138−instance MonadNodeId m => MonadNodeId (Input t m)
139−
140−-- | Runs an 'Input' with a given context
141−runInput
142− :: Reflex t
143− => Event t VtyEvent
144− -> Input t m a
145− -> m a
146−runInput e w = runReaderT (unInput w) e
147−
148−-- ** Filtering input
149−
150−-- | Type synonym for a key and modifier combination
151−type KeyCombo = (V.Key, [V.Modifier])
152−
153−-- | Emits an event that fires on a particular key press (without modifiers)
154−key :: (Monad m, Reflex t, HasInput t m) => V.Key -> m (Event t KeyCombo)
155−key = keyCombos . Set.singleton . (,[])
156−
157−-- | Emits an event that fires on particular key presses (without modifiers)
158−keys :: (Monad m, Reflex t, HasInput t m) => [V.Key] -> m (Event t KeyCombo)
159−keys = keyCombos . Set.fromList . fmap (,[])
160−
161−-- | Emit an event that fires whenever the provided key combination occurs
162−keyCombo
163− :: (Reflex t, Monad m, HasInput t m)
164− => KeyCombo
165− -> m (Event t KeyCombo)
166−keyCombo = keyCombos . Set.singleton
167−
168−-- | Emit an event that fires whenever any of the provided key combinations occur
169−keyCombos
170− :: (Reflex t, Monad m, HasInput t m)
171− => Set KeyCombo
172− -> m (Event t KeyCombo)
173−keyCombos ks = do
174− i <- input
175− return $ fforMaybe i $ \case
176− V.EvKey k m -> if Set.member (k, m) ks
177− then Just (k, m)
178− else Nothing
179− _ -> Nothing
180151
181−-- | Filter the keyboard input that a child widget may receive
182−filterKeys :: (Reflex t, HasInput t m) => (KeyCombo -> Bool) -> m a -> m a
183−filterKeys f x = localInput (ffilter (\case
184− V.EvKey k mods -> f (k, mods)
185− _ -> True)) x
186−
187−-- | Filter mouse input events based on whether they target a particular region
188−-- and translate them to the internal coordinate system of that region.
189−--
190−-- NB: Non-mouse events are passed through unfiltered and unchanged
191−mouseInRegion :: Region -> VtyEvent -> Maybe VtyEvent
192−mouseInRegion (Region l t w h) e = case e of
193− V.EvMouseDown x y btn m -> mouse (\u v -> V.EvMouseDown u v btn m) x y
194− V.EvMouseUp x y btn -> mouse (\u v -> V.EvMouseUp u v btn) x y
195− _ -> Just e
196− where
197− mouse con x y
198− | or [ x < l
199− , y < t
200− , x >= l + w
201− , y >= t + h ] = Nothing
202− | otherwise =
203− Just (con (x - l) (y - t))
204−
205−-- | Filter mouse input outside the current display region and
206−-- all input if the region is not focused
207−inputInFocusedRegion
208− :: (HasDisplayRegion t m, HasFocusReader t m, HasInput t m)
209− => m (Event t VtyEvent)
210−inputInFocusedRegion = do
211− inp <- input
212− reg <- current <$> askRegion
213− foc <- current <$> focus
214− pure $ fmapMaybe id $ attachWith filterInput ((,) <$> reg <*> foc) inp
215− where
216− filterInput (r, f) = \case
217− V.EvKey {} | not f -> Nothing
218− x -> mouseInRegion r x
152+instance (Reflex t, Monad m) => HasVtyInput t (VtyWidget t m) where
153+ input = VtyWidget . lift $ asks _vtyWidgetCtx_input
154+
155+class HasFocus t m | m -> t where
156+ focus :: m (Dynamic t Bool)
157+
158+instance (Reflex t, Monad m) => HasFocus t (VtyWidget t m) where
159+ focus = VtyWidget . lift $ asks _vtyWidgetCtx_focus
160+
161+class (Reflex t, Monad m) => ImageWriter t m | m -> t where
162+ tellImages :: Behavior t [Image] -> m ()
163+
164+instance (Reflex t, Monad m) => ImageWriter t (VtyWidget t m) where
165+ tellImages imgs = VtyWidget $ tell (mempty { _vtyWidgetOut_images = imgs })
166+
167+class (Reflex t, Monad m) => Shutdown t m where
168+ tellShutdown :: Event t () -> m ()
219169
220−-- * Getting and setting the display region
170+instance (Reflex t, Monad m) => Shutdown t (VtyWidget t m) where
171+ tellShutdown sd = VtyWidget $ tell (mempty { _vtyWidgetOut_shutdown = sd })
221172
222−-- | A chunk of the display area
223173data Region = Region
224174 { _region_left :: Int
225175 , _region_top :: Int
@@ -228,334 +178,432 @@ data Region = Region
228178 }
229179 deriving (Show, Read, Eq, Ord)
230180
231−-- | A region that occupies no space.
232−nilRegion :: Region
233−nilRegion = Region 0 0 0 0
234−
235−-- | The width and height of a 'Region'
236181regionSize :: Region -> (Int, Int)
237182regionSize (Region _ _ w h) = (w, h)
238183
239−-- | Produces an 'Image' that fills a region with space characters
240−regionBlankImage :: V.Attr -> Region -> Image
241−regionBlankImage attr r@(Region _ _ width height) =
242− withinImage r $ V.charFill attr ' ' width height
243−
244−-- | A class for things that know their own display size dimensions
245−class (Reflex t, Monad m) => HasDisplayRegion t m | m -> t where
246− -- | Retrieve the display region
247− askRegion :: m (Dynamic t Region)
248− default askRegion :: (f m' ~ m, MonadTrans f, HasDisplayRegion t m') => m (Dynamic t Region)
249− askRegion = lift askRegion
250− -- | Run an action in a local region, by applying a transformation to the region
251− localRegion :: (Dynamic t Region -> Dynamic t Region) -> m a -> m a
252− default localRegion :: (f m' ~ m, Monad m', MFunctor f, HasDisplayRegion t m') => (Dynamic t Region -> Dynamic t Region) -> m a -> m a
253− localRegion f = hoist (localRegion f)
254−
255−-- | Retrieve the display width
256−displayWidth :: HasDisplayRegion t m => m (Dynamic t Int)
257−displayWidth = fmap _region_width <$> askRegion
258−
259−-- | Retrieve the display height
260−displayHeight :: HasDisplayRegion t m => m (Dynamic t Int)
261−displayHeight = fmap _region_height <$> askRegion
262−
263−instance HasDisplayRegion t m => HasDisplayRegion t (ReaderT x m)
264−instance HasDisplayRegion t m => HasDisplayRegion t (BehaviorWriterT t x m)
265−instance HasDisplayRegion t m => HasDisplayRegion t (DynamicWriterT t x m)
266−instance HasDisplayRegion t m => HasDisplayRegion t (EventWriterT t x m)
267−instance HasDisplayRegion t m => HasDisplayRegion t (NodeIdT m)
268−
269−-- | A widget that has access to a particular region of the vty display
270−newtype DisplayRegion t m a = DisplayRegion
271− { unDisplayRegion :: ReaderT (Dynamic t Region) m a }
272− deriving
273− ( Functor
274− , Applicative
275− , Monad
276− , MonadFix
277− , MonadHold t
278− , MonadIO
279− , MonadRef
280− , MonadSample t
281− )
282−
283−instance (Monad m, Reflex t) => HasDisplayRegion t (DisplayRegion t m) where
284− askRegion = DisplayRegion ask
285− localRegion f = DisplayRegion . local f . unDisplayRegion
286−
287−deriving instance MonadReflexCreateTrigger t m => MonadReflexCreateTrigger t (DisplayRegion t m)
288−deriving instance NotReady t m => NotReady t (DisplayRegion t m)
289−deriving instance PerformEvent t m => PerformEvent t (DisplayRegion t m)
290−deriving instance PostBuild t m => PostBuild t (DisplayRegion t m)
291−deriving instance TriggerEvent t m => TriggerEvent t (DisplayRegion t m)
292−instance HasImageWriter t m => HasImageWriter t (DisplayRegion t m)
293−instance HasFocusReader t m => HasFocusReader t (DisplayRegion t m)
294−
295−instance (Adjustable t m, MonadFix m, MonadHold t m) => Adjustable t (DisplayRegion t m) where
296− runWithReplace (DisplayRegion a) e = DisplayRegion $ runWithReplace a $ fmap unDisplayRegion e
297− traverseIntMapWithKeyWithAdjust f m e = DisplayRegion $ traverseIntMapWithKeyWithAdjust (\k v -> unDisplayRegion $ f k v) m e
298− traverseDMapWithKeyWithAdjust f m e = DisplayRegion $ traverseDMapWithKeyWithAdjust (\k v -> unDisplayRegion $ f k v) m e
299− traverseDMapWithKeyWithAdjustWithMove f m e = DisplayRegion $ traverseDMapWithKeyWithAdjustWithMove (\k v -> unDisplayRegion $ f k v) m e
300−
301−instance MonadTrans (DisplayRegion t) where
302− lift = DisplayRegion . lift
303−
304−instance MFunctor (DisplayRegion t) where
305− hoist f = DisplayRegion . hoist f . unDisplayRegion
306−
307−instance MonadNodeId m => MonadNodeId (DisplayRegion t m)
308−
309−-- | Run a 'DisplayRegion' action with a given 'Region'
310−runDisplayRegion
184+pane
311185 :: (Reflex t, Monad m)
312− => Dynamic t Region
313− -> DisplayRegion t m a
314− -> m a
315−runDisplayRegion r = flip runReaderT r . unDisplayRegion
316−
317−-- * Getting focus state
186+ => Dynamic t Region -- ^ Region into which we should draw the widget (in coordinates relative to our own)
187+ -> Dynamic t Bool -- ^ Whether the widget should be focused when the parent is.
188+ -> VtyWidget t m a
189+ -> VtyWidget t m a
190+pane reg foc child = VtyWidget $ do
191+ ctx <- lift ask
192+ let ctx' = VtyWidgetCtx
193+ { _vtyWidgetCtx_input = leftmost -- TODO: think about this leftmost more.
194+ [ fmapMaybe id $
195+ attachWith (\(r,f) e -> filterInput r f e)
196+ (liftA2 (,) (current reg) (current foc))
197+ (_vtyWidgetCtx_input ctx)
198+ ]
199+ , _vtyWidgetCtx_focus = liftA2 (&&) (_vtyWidgetCtx_focus ctx) foc
200+ , _vtyWidgetCtx_size = fmap regionSize reg }
201+ (result, wo) <- lift . lift $ runVtyWidget ctx' child
202+ let images = _vtyWidgetOut_images wo
203+ images' = liftA2 (\r is -> map (withinImage r) is) (current reg) images
204+ wo' = wo { _vtyWidgetOut_images = images' }
205+ tell wo'
206+ return result
207+ where
208+ -- Filters input such that:
209+ -- * unfocused widgets receive no key events
210+ -- * mouse inputs outside the region are ignored
211+ -- * mouse inputs inside the region have their coordinates translated
212+ -- such that (0,0) is the top-left corner of the region
213+ filterInput :: Region -> Bool -> VtyEvent -> Maybe VtyEvent
214+ filterInput (Region l t w h) focused e = case e of
215+ V.EvKey _ _ | not focused -> Nothing
216+ V.EvMouseDown x y btn m -> mouse (\u v -> V.EvMouseDown u v btn m) x y
217+ V.EvMouseUp x y btn -> mouse (\u v -> V.EvMouseUp u v btn) x y
218+ _ -> Just e
219+ where
220+ mouse con x y
221+ | or [ x < l
222+ , y < t
223+ , x >= l + w
224+ , y >= t + h ] = Nothing
225+ | otherwise =
226+ Just (con (x - l) (y - t))
227+
228+data Drag = Drag
229+ { _drag_from :: (Int, Int) -- ^ Where the drag began
230+ , _drag_to :: (Int, Int) -- ^ Where the mouse currently is
231+ , _drag_button :: V.Button -- ^ Which mouse button is dragging
232+ , _drag_modifiers :: [V.Modifier] -- ^ What modifiers are held
233+ , _drag_end :: Bool -- ^ Whether the drag ended (the mouse button was released)
234+ }
235+ deriving (Eq, Ord, Show)
318236
319−-- | A class for things that can dynamically gain and lose focus
320−class (Reflex t, Monad m) => HasFocusReader t m | m -> t where
321− focus :: m (Dynamic t Bool)
322− default focus :: (f m' ~ m, Monad m', MonadTrans f, HasFocusReader t m') => m (Dynamic t Bool)
323− focus = lift focus
324− localFocus :: (Dynamic t Bool -> Dynamic t Bool) -> m a -> m a
325− default localFocus :: (f m' ~ m, Monad m', MFunctor f, HasFocusReader t m') => (Dynamic t Bool -> Dynamic t Bool) -> m a -> m a
326− localFocus f = hoist (localFocus f)
327−
328−instance HasFocusReader t m => HasFocusReader t (ReaderT x m)
329−instance HasFocusReader t m => HasFocusReader t (BehaviorWriterT t x m)
330−instance HasFocusReader t m => HasFocusReader t (DynamicWriterT t x m)
331−instance HasFocusReader t m => HasFocusReader t (EventWriterT t x m)
332−instance HasFocusReader t m => HasFocusReader t (NodeIdT m)
333−
334−-- | A widget that has access to information about whether it is focused
335−newtype FocusReader t m a = FocusReader
336− { unFocusReader :: ReaderT (Dynamic t Bool) m a }
337− deriving
338− ( Functor
339− , Applicative
340− , Monad
341− , MonadFix
342− , MonadHold t
343− , MonadIO
344− , MonadRef
345− , MonadSample t
346− )
347−
348−instance (Monad m, Reflex t) => HasFocusReader t (FocusReader t m) where
349− focus = FocusReader ask
350− localFocus f = FocusReader . local f . unFocusReader
351−
352−deriving instance MonadReflexCreateTrigger t m => MonadReflexCreateTrigger t (FocusReader t m)
353−deriving instance NotReady t m => NotReady t (FocusReader t m)
354−deriving instance PerformEvent t m => PerformEvent t (FocusReader t m)
355−deriving instance PostBuild t m => PostBuild t (FocusReader t m)
356−deriving instance TriggerEvent t m => TriggerEvent t (FocusReader t m)
357−instance HasImageWriter t m => HasImageWriter t (FocusReader t m)
358−
359−instance (Adjustable t m, MonadFix m, MonadHold t m) => Adjustable t (FocusReader t m) where
360− runWithReplace (FocusReader a) e = FocusReader $ runWithReplace a $ fmap unFocusReader e
361− traverseIntMapWithKeyWithAdjust f m e = FocusReader $ traverseIntMapWithKeyWithAdjust (\k v -> unFocusReader $ f k v) m e
362− traverseDMapWithKeyWithAdjust f m e = FocusReader $ traverseDMapWithKeyWithAdjust (\k v -> unFocusReader $ f k v) m e
363− traverseDMapWithKeyWithAdjustWithMove f m e = FocusReader $ traverseDMapWithKeyWithAdjustWithMove (\k v -> unFocusReader $ f k v) m e
364−
365−instance MonadTrans (FocusReader t) where
366− lift = FocusReader . lift
367−
368−instance MFunctor (FocusReader t) where
369− hoist f = FocusReader . hoist f . unFocusReader
370−
371−instance MonadNodeId m => MonadNodeId (FocusReader t m)
372−
373−-- | Run a 'FocusReader' action with the given focus value
374−runFocusReader
237+drag
238+ :: (Reflex t, MonadFix m, MonadHold t m)
239+ => V.Button
240+ -> VtyWidget t m (Event t Drag)
241+drag btn = do
242+ inp <- input
243+ let f :: Drag -> V.Event -> Maybe Drag
244+ f (Drag from _ _ mods end) = \case
245+ V.EvMouseDown x y btn' mods'
246+ | end -> Just $ Drag (x,y) (x,y) btn' mods' False
247+ | btn == btn' -> Just $ Drag from (x,y) btn mods' False
248+ | otherwise -> Nothing -- Ignore other buttons.
249+ V.EvMouseUp x y (Just btn')
250+ | end -> Nothing
251+ | btn == btn' -> Just $ Drag from (x,y) btn mods True
252+ | otherwise -> Nothing
253+ V.EvMouseUp x y Nothing -- Terminal doesn't specify mouse up button,
254+ -- assume it's the right one.
255+ | end -> Nothing
256+ | otherwise -> Just $ Drag from (x,y) btn mods True
257+ _ -> Nothing
258+ rec let newDrag = attachWithMaybe f (current dragD) inp
259+ dragD <- holdDyn (Drag (0,0) (0,0) btn [] True) -- gross, but ok because it'll never be produced.
260+ newDrag
261+ return (updated dragD)
262+
263+mouseDown
375264 :: (Reflex t, Monad m)
376− => Dynamic t Bool
377− -> FocusReader t m a
378− -> m a
379−runFocusReader b = flip runReaderT b . unFocusReader
265+ => V.Button
266+ -> VtyWidget t m (Event t VtyEvent)
267+mouseDown btn = do
268+ i <- input
269+ return $ fforMaybe i $ \x -> case x of
270+ V.EvMouseDown _ _ btn' _ -> if btn == btn' then Just x else Nothing
271+ _ -> Nothing
380272
381−-- * "Image" output
273+-- | A plain split of the available space into vertically stacked panes.
274+-- No visual separator is built in here.
275+splitV :: (Reflex t, Monad m)
276+ => Dynamic t (Int -> Int)
277+ -- ^ Function used to determine size of first pane based on available size
278+ -> Dynamic t (Bool, Bool)
279+ -- ^ How to focus the two sub-panes, given that we are focused.
280+ -> VtyWidget t m a
281+ -- ^ Widget for first pane
282+ -> VtyWidget t m b
283+ -- ^ Widget for second pane
284+ -> VtyWidget t m (a,b)
285+splitV sizeFunD focD wA wB = do
286+ sz <- displaySize
287+ let regA = (\f (w,h) -> Region 0 0 w (f h)) <$> sizeFunD <*> sz
288+ regB = (\(w,h) (Region _ _ _ hA) -> Region 0 hA w (h - hA)) <$> sz <*> regA
289+ ra <- pane regA (fst <$> focD) wA
290+ rb <- pane regB (snd <$> focD) wB
291+ return (ra,rb)
292+
293+-- | A split of the available space into two parts with a draggable separator.
294+-- Starts with half the space allocated to each, and the first pane has focus.
295+-- Clicking in a pane switches focus.
296+splitVDrag :: (Reflex t, MonadFix m, MonadHold t m)
297+ => VtyWidget t m ()
298+ -> VtyWidget t m a
299+ -> VtyWidget t m b
300+ -> VtyWidget t m (a,b)
301+splitVDrag wS wA wB = do
302+ sz <- displaySize
303+ (_, h0) <- sample $ current sz
304+ dragE <- drag V.BLeft
305+ let splitter0 = h0 `div` 2
306+ rec splitterCheckpoint <- holdDyn splitter0 $ leftmost [fst <$> ffilter snd dragSplitter, resizeSplitter]
307+ splitterPos <- holdDyn splitter0 $ leftmost [fst <$> dragSplitter, resizeSplitter]
308+ splitterFrac <- holdDyn ((1::Double) / 2) $ ffor (attach (current sz) (fst <$> dragSplitter)) $ \((_,h),x) ->
309+ fromIntegral x / fromIntegral h
310+ let dragSplitter = fforMaybe (attach (current splitterCheckpoint) dragE) $
311+ \(splitterY, Drag (_, fromY) (_, toY) _ _ end) ->
312+ if splitterY == fromY then Just (toY, end) else Nothing
313+ regA = (\(w,_) sp -> Region 0 0 w sp) <$> sz <*> splitterPos
314+ regS = (\(w,_) sp -> Region 0 sp w 1) <$> sz <*> splitterPos
315+ regB = (\(w,h) sp -> Region 0 (sp + 1) w (h - sp - 1)) <$> sz <*> splitterPos
316+ resizeSplitter = ffor (attach (current splitterFrac) (updated sz)) $
317+ \(frac, (_,h)) -> round (frac * fromIntegral h)
318+ focA <- holdDyn True $ leftmost
319+ [ True <$ mA
320+ , False <$ mB
321+ ]
322+ (mA, rA) <- pane regA focA $ withMouseDown wA
323+ pane regS (pure False) wS
324+ (mB, rB) <- pane regB (not <$> focA) $ withMouseDown wB
325+ return (rA, rB)
326+ where
327+ withMouseDown x = do
328+ m <- mouseDown V.BLeft
329+ x' <- x
330+ return (m, x')
331+
332+-- | Fill the background with a particular character.
333+fill :: (Reflex t, Monad m) => Char -> VtyWidget t m ()
334+fill c = do
335+ sz <- displaySize
336+ let fillImg = ffor (current sz) $ \(w,h) -> [V.charFill V.defAttr c w h]
337+ tellImages fillImg
338+
339+-- | Fill the background with the bottom
340+hRule :: (Reflex t, Monad m) => BoxStyle -> VtyWidget t m ()
341+hRule boxStyle = fill (_boxStyle_s boxStyle)
342+
343+fractionSz :: Double -> Int -> Int
344+fractionSz x h = round (fromIntegral h * x)
345+
346+modifyImages
347+ :: (Reflex t, MonadHold t m, MonadFix m)
348+ => Behavior t ([Image] -> [Image])
349+ -> VtyWidget t m a
350+ -> VtyWidget t m a
351+modifyImages f (VtyWidget w) = VtyWidget $ flip censor w $ \wo ->
352+ wo { _vtyWidgetOut_images = f <*> (_vtyWidgetOut_images wo) }
353+
354+data BoxStyle = BoxStyle
355+ { _boxStyle_nw :: Char
356+ , _boxStyle_n :: Char
357+ , _boxStyle_ne :: Char
358+ , _boxStyle_e :: Char
359+ , _boxStyle_se :: Char
360+ , _boxStyle_s :: Char
361+ , _boxStyle_sw :: Char
362+ , _boxStyle_w :: Char
363+ }
382364
383−-- | A class for widgets that can produce images to draw to the display
384−class (Reflex t, Monad m) => HasImageWriter t m | m -> t where
385− -- | Send images upstream for rendering
386− tellImages :: Behavior t [Image] -> m ()
387− default tellImages :: (f m' ~ m, Monad m', MonadTrans f, HasImageWriter t m') => Behavior t [Image] -> m ()
388− tellImages = lift . tellImages
389− -- | Apply a transformation to the images produced by the child actions
390− mapImages :: (Behavior t [Image] -> Behavior t [Image]) -> m a -> m a
391− default mapImages :: (f m' ~ m, Monad m', MFunctor f, HasImageWriter t m') => (Behavior t [Image] -> Behavior t [Image]) -> m a -> m a
392− mapImages f = hoist (mapImages f)
393−
394−-- | A widget that can produce images to draw onto the display
395−newtype ImageWriter t m a = ImageWriter
396− { unImageWriter :: BehaviorWriterT t [Image] m a }
397− deriving
398− ( Functor
399− , Applicative
400− , Monad
401− , MonadFix
402− , MonadHold t
403− , MonadIO
404− , MonadRef
405− , MonadReflexCreateTrigger t
406− , MonadSample t
407− , NotReady t
408− , PerformEvent t
409− , PostBuild t
410− , TriggerEvent t
411− )
412−
413−instance MonadTrans (ImageWriter t) where
414− lift = ImageWriter . lift
415−
416−instance MFunctor (ImageWriter t) where
417− hoist f = ImageWriter . (hoist f) . unImageWriter
418−
419−instance (Adjustable t m, MonadFix m, MonadHold t m) => Adjustable t (ImageWriter t m) where
420− runWithReplace (ImageWriter a) e = ImageWriter $ runWithReplace a $ fmap unImageWriter e
421− traverseIntMapWithKeyWithAdjust f m e = ImageWriter $ traverseIntMapWithKeyWithAdjust (\k v -> unImageWriter $ f k v) m e
422− traverseDMapWithKeyWithAdjust f m e = ImageWriter $ traverseDMapWithKeyWithAdjust (\k v -> unImageWriter $ f k v) m e
423− traverseDMapWithKeyWithAdjustWithMove f m e = ImageWriter $ traverseDMapWithKeyWithAdjustWithMove (\k v -> unImageWriter $ f k v) m e
424−
425−instance HasImageWriter t m => HasImageWriter t (ReaderT x m)
426−instance HasImageWriter t m => HasImageWriter t (BehaviorWriterT t x m)
427−instance HasImageWriter t m => HasImageWriter t (DynamicWriterT t x m)
428−instance HasImageWriter t m => HasImageWriter t (EventWriterT t x m)
429−instance HasImageWriter t m => HasImageWriter t (NodeIdT m)
430−
431−instance (Monad m, Reflex t) => HasImageWriter t (ImageWriter t m) where
432− tellImages = ImageWriter . tellBehavior
433− mapImages f (ImageWriter x) = ImageWriter $ do
434− (a, images) <- lift $ runBehaviorWriterT x
435− tellBehavior $ f images
436− pure a
437−
438−instance HasDisplayRegion t m => HasDisplayRegion t (ImageWriter t m)
439−instance HasFocusReader t m => HasFocusReader t (ImageWriter t m)
440−
441−-- | Run a widget that can produce images
442−runImageWriter
443− :: (Reflex t, Monad m)
444− => ImageWriter t m a
445− -> m (a, Behavior t [Image])
446−runImageWriter = runBehaviorWriterT . unImageWriter
447−
448−-- * Theming
449−
450−-- | A class for things that can be visually styled
451−class (Reflex t, Monad m) => HasTheme t m | m -> t where
452− theme :: m (Behavior t V.Attr)
453− default theme :: (f m' ~ m, Monad m', MonadTrans f, HasTheme t m') => m (Behavior t V.Attr)
454− theme = lift theme
455− localTheme :: (Behavior t V.Attr -> Behavior t V.Attr) -> m a -> m a
456− default localTheme :: (f m' ~ m, Monad m', MFunctor f, HasTheme t m') => (Behavior t V.Attr -> Behavior t V.Attr) -> m a -> m a
457− localTheme f = hoist (localTheme f)
458−
459−instance HasTheme t m => HasTheme t (ReaderT x m)
460−instance HasTheme t m => HasTheme t (BehaviorWriterT t x m)
461−instance HasTheme t m => HasTheme t (DynamicWriterT t x m)
462−instance HasTheme t m => HasTheme t (EventWriterT t x m)
463−instance HasTheme t m => HasTheme t (NodeIdT m)
464−instance HasTheme t m => HasTheme t (Input t m)
465−instance HasTheme t m => HasTheme t (ImageWriter t m)
466−instance HasTheme t m => HasTheme t (DisplayRegion t m)
467−instance HasTheme t m => HasTheme t (FocusReader t m)
468−
469−-- | A widget that has access to theme information
470−newtype ThemeReader t m a = ThemeReader
471− { unThemeReader :: ReaderT (Behavior t V.Attr) m a }
472− deriving
473− ( Functor
474− , Applicative
475− , Monad
476− , MonadFix
477− , MonadHold t
478− , MonadIO
479− , MonadRef
480− , MonadSample t
481− )
482−
483−instance (Monad m, Reflex t) => HasTheme t (ThemeReader t m) where
484− theme = ThemeReader ask
485− localTheme f = ThemeReader . local f . unThemeReader
486−
487−deriving instance MonadReflexCreateTrigger t m => MonadReflexCreateTrigger t (ThemeReader t m)
488−deriving instance NotReady t m => NotReady t (ThemeReader t m)
489−deriving instance PerformEvent t m => PerformEvent t (ThemeReader t m)
490−deriving instance PostBuild t m => PostBuild t (ThemeReader t m)
491−deriving instance TriggerEvent t m => TriggerEvent t (ThemeReader t m)
492−instance HasImageWriter t m => HasImageWriter t (ThemeReader t m)
493−
494−instance (Adjustable t m, MonadFix m, MonadHold t m) => Adjustable t (ThemeReader t m) where
495− runWithReplace (ThemeReader a) e = ThemeReader $ runWithReplace a $ fmap unThemeReader e
496− traverseIntMapWithKeyWithAdjust f m e = ThemeReader $ traverseIntMapWithKeyWithAdjust (\k v -> unThemeReader $ f k v) m e
497− traverseDMapWithKeyWithAdjust f m e = ThemeReader $ traverseDMapWithKeyWithAdjust (\k v -> unThemeReader $ f k v) m e
498− traverseDMapWithKeyWithAdjustWithMove f m e = ThemeReader $ traverseDMapWithKeyWithAdjustWithMove (\k v -> unThemeReader $ f k v) m e
499−
500−instance MonadTrans (ThemeReader t) where
501− lift = ThemeReader . lift
502−
503−instance MFunctor (ThemeReader t) where
504− hoist f = ThemeReader . hoist f . unThemeReader
505−
506−instance MonadNodeId m => MonadNodeId (ThemeReader t m)
507−
508−-- | Run a 'ThemeReader' action with the given focus value
509−runThemeReader
510− :: (Reflex t, Monad m)
511− => Behavior t V.Attr
512− -> ThemeReader t m a
513− -> m a
514−runThemeReader b = flip runReaderT b . unThemeReader
365+instance Default BoxStyle where
366+ def = singleBoxStyle
515367
368+hyphenBoxStyle :: BoxStyle
369+hyphenBoxStyle = BoxStyle '-' '-' '-' '|' '-' '-' '-' '|'
516370
517−-- ** Manipulating images
371+singleBoxStyle :: BoxStyle
372+singleBoxStyle = BoxStyle '┌' '─' '┐' '│' '┘' '─' '└' '│'
518373
519−-- | Translates and crops an 'Image' so that it is contained by
520−-- the given 'Region'.
521−withinImage
522− :: Region
523− -> Image
524− -> Image
374+thickBoxStyle :: BoxStyle
375+thickBoxStyle = BoxStyle '┏' '━' '┓' '┃' '┛' '━' '┗' '┃'
376+
377+doubleBoxStyle :: BoxStyle
378+doubleBoxStyle = BoxStyle '╔' '═' '╗' '║' '╝' '═' '╚' '║'
379+
380+roundedBoxStyle :: BoxStyle
381+roundedBoxStyle = BoxStyle '╭' '─' '╮' '│' '╯' '─' '╰' '│'
382+
383+box :: (Monad m, Reflex t)
384+ => BoxStyle
385+ -> VtyWidget t m a
386+ -> VtyWidget t m a
387+box style child = do
388+ sz <- displaySize
389+ let boxReg = ffor (current sz) $ \(w,h) -> Region 0 0 w h
390+ innerReg = ffor sz $ \(w,h) -> Region 1 1 (w - 2) (h - 2)
391+ tellImages (fmap boxImages boxReg)
392+ tellImages (fmap (\r -> [regionBlankImage r]) (current innerReg))
393+ pane innerReg (pure True) child
394+ where
395+ boxImages :: Region -> [Image]
396+ boxImages (Region left top width height) =
397+ let right = left + width - 1
398+ bottom = top + height - 1
399+ sides =
400+ [ withinImage (Region (left + 1) top (width - 2) 1) $
401+ V.charFill V.defAttr (_boxStyle_n style) (width - 2) 1
402+ , withinImage (Region right (top + 1) 1 (height - 2)) $
403+ V.charFill V.defAttr (_boxStyle_e style) 1 (height - 2)
404+ , withinImage (Region (left + 1) bottom (width - 2) 1) $
405+ V.charFill V.defAttr (_boxStyle_s style) (width - 2) 1
406+ , withinImage (Region left (top + 1) 1 (height - 2)) $
407+ V.charFill V.defAttr (_boxStyle_w style) 1 (height - 2)
408+ ]
409+ corners =
410+ [ withinImage (Region left top 1 1) $
411+ V.char V.defAttr (_boxStyle_nw style)
412+ , withinImage (Region right top 1 1) $
413+ V.char V.defAttr (_boxStyle_ne style)
414+ , withinImage (Region right bottom 1 1) $
415+ V.char V.defAttr (_boxStyle_se style)
416+ , withinImage (Region left bottom 1 1) $
417+ V.char V.defAttr (_boxStyle_sw style)
418+ ]
419+ in sides ++ if width > 1 && height > 1 then corners else []
420+
421+text :: (Reflex t, Monad m) => Behavior t Text -> VtyWidget t m ()
422+text msg = do
423+ dw <- displayWidth
424+ let img = (\w s -> [wrapText w V.defAttr s]) <$> current dw <*> msg
425+ tellImages img
426+
427+display :: (Reflex t, Monad m, Show a) => Behavior t a -> VtyWidget t m ()
428+display a = text $ T.pack . show <$> a
429+
430+regionBlankImage :: Region -> Image
431+regionBlankImage r@(Region _ _ width height) =
432+ withinImage r $ V.charFill V.defAttr ' ' width height
433+
434+withinImage :: Region -> Image -> Image
525435withinImage (Region left top width height)
526436 | width < 0 || height < 0 = withinImage (Region left top 0 0)
527437 | otherwise = V.translate left top . V.crop width height
528438
529−-- | Crop a behavior of images to a behavior of regions. See 'withinImage'.
530−imagesInRegion
531− :: Reflex t
532− => Behavior t Region
533− -> Behavior t [Image]
534− -> Behavior t [Image]
535−imagesInRegion reg = liftA2 (\r is -> map (withinImage r) is) reg
536−
537−-- * Running sub-widgets
538−
539−-- | Low-level widget combinator that runs a child widget within
540−-- a given region and context. This widget filters and modifies the input
541−-- that the child widget receives such that:
542−-- * unfocused widgets receive no key events
543−-- * mouse inputs outside the region are ignored
544−-- * mouse inputs inside the region have their coordinates translated such
545−-- that (0,0) is the top-left corner of the region
546−pane
547− :: (Reflex t, Monad m, HasInput t m, HasImageWriter t m, HasDisplayRegion t m, HasFocusReader t m)
548− => Dynamic t Region
549− -> Dynamic t Bool -- ^ Whether the widget should be focused when the parent is.
550− -> m a
551− -> m a
552−pane dr foc child = localRegion (const dr) $
553− mapImages (imagesInRegion $ current dr) $
554− localFocus (const foc) $
555− inputInFocusedRegion >>= \e -> localInput (const e) child
556−
557−-- * Misc
558−
559−-- | A widget that draws nothing
560−blank :: Monad m => m ()
561−blank = return ()
439+wrapText :: Int -> Attr -> Text -> Image
440+wrapText maxWidth attrs = V.vertCat
441+ . concatMap (fmap (V.string attrs . T.unpack) . wrapWithOffset maxWidth 0)
442+ . T.split (=='\n')
443+
444+wrapWithOffset :: Int -> Int -> Text -> [Text]
445+wrapWithOffset maxWidth n xs =
446+ let (firstLine, rest) = T.splitAt (maxWidth - n) xs
447+ in firstLine : (fmap (T.take maxWidth) . takeWhile (not . T.null) . iterate (T.drop maxWidth) $ rest)
448+
449+wrapInputState
450+ :: Int -- ^ Maximum line length
451+ -> Attr -- ^ Normal string attributes
452+ -> Attr -- ^ Cursor character attributes
453+ -> InputState -- ^ The input to render
454+ -> ([Image], Int)
455+wrapInputState maxWidth attrs cursorAttrs (InputState before after) =
456+ let -- Break up the InputState into:
457+ -- * A top section of lines before the line containing the cursor
458+ -- * A part of the line containing the cursor that comes immediately before the cursor
459+ -- * The cursor character (i.e., the character the cursor is on top of)
460+ -- * The remainder of the line containing the cursor
461+ -- * The bottom section of lines after the line containing the cursor
462+ (top, midBefore, cursorChar, midAfter, bottom) = case (initLast before', headTail after') of
463+ (Nothing, Nothing) -> ([], "", ' ', "", [])
464+ (Just (top', mid), Nothing) -> (top', mid, ' ', "", [])
465+ (Nothing, Just (mid, bottom')) -> case T.uncons mid of
466+ Nothing -> ([], "", ' ', "", bottom')
467+ Just (c, rest) -> ([], "", c, rest, bottom')
468+ (Just (top', midB), Just (midA, bottom')) -> case T.uncons midA of
469+ Nothing -> (top', midB, ' ', "", bottom')
470+ Just (c, rest) -> (top', midB, c, rest, bottom')
471+ (midBeforeTop, midBefore') = fromMaybe ([], "") $ initLast $ wrap [midBefore]
472+ cursorAfterEOL = T.length midBefore' == maxWidth
473+ (midAfter', midAfterBottom) =
474+ let offset = if cursorAfterEOL then 1 else T.length midBefore' + 1
475+ in case wrapWithOffset maxWidth offset midAfter of
476+ [] -> ("", [])
477+ x:xs -> (x, xs)
478+ cursor = V.char cursorAttrs cursorChar
479+ images = mconcat
480+ [ vstring <$> wrap top
481+ , vstring <$> midBeforeTop
482+ , if cursorAfterEOL
483+ then
484+ [ vstring midBefore'
485+ , V.horizCat
486+ [ cursor
487+ , vstring midAfter'
488+ ]
489+ ]
490+ else
491+ [ V.horizCat
492+ [ vstring midBefore'
493+ , cursor
494+ , vstring midAfter'
495+ ]
496+ ]
497+ , vstring <$> midAfterBottom
498+ , vstring <$> bottom
499+ ]
500+ cursorY = length top + length midBeforeTop + if cursorAfterEOL then 1 else 0
501+ in (images, cursorY)
502+ where
503+ before' = T.split (=='\n') before
504+ after' = T.split (=='\n') after
505+ vstring = V.string attrs . T.unpack
506+ wrap :: [Text] -> [Text]
507+ wrap = concatMap (wrapWithOffset maxWidth 0)
508+ headTail :: [a] -> Maybe (a, [a])
509+ headTail = \case
510+ [] -> Nothing
511+ x:xs -> Just (x, xs)
512+ initLast :: [a] -> Maybe ([a], a)
513+ initLast = \case
514+ [] -> Nothing
515+ (x:xs) -> case initLast xs of
516+ Nothing -> Just ([], x)
517+ Just (ys, y) -> Just (x:ys, y)
518+
519+data InputState = InputState
520+ { _inputState_beforeCursor :: Text
521+ , _inputState_afterCursor :: Text
522+ }
523+
524+inputValue :: InputState -> Text
525+inputValue (InputState a b) = a <> b
526+
527+updateInputState :: V.Event -> InputState -> InputState
528+updateInputState ev i@(InputState before after) = case ev of
529+ -- Regular characters
530+ V.EvKey (V.KChar k) [] -> InputState (T.snoc before k) after
531+ -- Deletion buttons
532+ V.EvKey V.KBS [] -> InputState (if T.null before then T.empty else T.init before) after
533+ V.EvKey V.KDel [] -> case T.uncons after of
534+ Nothing -> i
535+ Just (_, a) -> InputState before a
536+ -- Key combinations
537+ V.EvKey (V.KChar 'u') [V.MCtrl] -> InputState mempty mempty
538+ V.EvKey (V.KChar 'w') [V.MCtrl] -> InputState (T.dropWhileEnd (not . isSpace) $ T.dropWhileEnd isSpace $ before) after
539+ -- Arrow keys
540+ V.EvKey V.KRight [] -> case T.uncons after of
541+ Nothing -> i
542+ Just (a, as) -> InputState (T.snoc before a) as
543+ V.EvKey V.KLeft [] -> case T.unsnoc before of
544+ Nothing -> i
545+ Just (bs, b) -> InputState bs (T.cons b after)
546+ V.EvKey V.KUp [] ->
547+ let (pre, post) = T.breakOnEnd "\n" before
548+ (top, previousLine) = T.breakOnEnd "\n" (T.dropEnd 1 pre)
549+ (previousLineBefore, previousLineAfter) = T.splitAt (T.length post) previousLine
550+ in if T.null pre
551+ then i
552+ else InputState (top <> previousLineBefore) (previousLineAfter <> "\n" <> post <> after)
553+ V.EvKey V.KDown [] ->
554+ let offset = T.length $ T.takeWhileEnd (/='\n') before
555+ (pre, post) = T.breakOn "\n" after
556+ (nextLine, rest) = T.breakOn "\n" (T.drop 1 post)
557+ (nextLineBefore, nextLineAfter) = T.splitAt offset nextLine
558+ in if T.null post
559+ then i
560+ else InputState (before <> pre <> "\n" <> nextLineBefore) (nextLineAfter <> rest)
561+ V.EvKey V.KHome [] ->
562+ let (pre, post) = T.breakOnEnd "\n" before
563+ in InputState pre (post <> after)
564+ V.EvKey V.KEnd [] ->
565+ let (pre, post) = T.breakOn "\n" after
566+ in InputState (before <> pre) post
567+ _ -> i
568+
569+data TextInputConfig t = TextInputConfig
570+ { _textInputConfig_initialValue :: Text
571+ , _textInputConfig_modifyInputState :: Event t (InputState -> InputState)
572+ }
573+
574+instance Reflex t => Default (TextInputConfig t) where
575+ def = TextInputConfig "" never
576+
577+textInput :: (Reflex t, MonadHold t m, MonadFix m) => TextInputConfig t -> VtyWidget t m (Dynamic t Text)
578+textInput cfg = do
579+ i <- input
580+ v <- foldDyn ($) (InputState (_textInputConfig_initialValue cfg) mempty) $ mergeWith (.)
581+ [ updateInputState <$> i
582+ , _textInputConfig_modifyInputState cfg
583+ ]
584+ dw <- displayWidth
585+ dh <- displayHeight
586+ let img = (\w s -> wrapInputState w V.defAttr (V.withStyle V.defAttr V.reverseVideo) s) -- TODO cursor ought to blink
587+ <$> dw
588+ <*> v
589+ y <- holdUniqDyn $ snd <$> img
590+ let newScrollTop st (h, cursorY)
591+ | cursorY < st = cursorY
592+ | cursorY >= st + h = cursorY - h + 1
593+ | otherwise = st
594+ rec let hy = attachWith newScrollTop (current scrollTop) $ updated $ zipDyn dh y
595+ scrollTop <- holdDyn 0 hy
596+ tellImages $ (\(imgs, _) st -> (:[]) . V.vertCat $ drop st imgs) <$> current img <*> current scrollTop
597+ return $ inputValue <$> v
598+
599+multilineTextInput :: (Reflex t, MonadHold t m, MonadFix m) => TextInputConfig t -> VtyWidget t m (Dynamic t Text)
600+multilineTextInput cfg = do
601+ i <- input
602+ textInput $ cfg
603+ { _textInputConfig_modifyInputState = mergeWith (.)
604+ [ fforMaybe i $ \case
605+ V.EvKey V.KEnter [] -> Just $ \(InputState before after) -> InputState (T.snoc before '\n') after
606+ _ -> Nothing
607+ , _textInputConfig_modifyInputState cfg
608+ ]
609+ }