@@ -2,41 +2,147 @@
22Module: Reflex.Vty.Widget
33Description: Basic set of widgets and building blocks for reflex-vty applications
44-}
5−{-# Language UndecidableInstances #-}
6−
7−module Reflex.Vty.Widget where
5+{-# LANGUAGE FlexibleContexts #-}
6+{-# LANGUAGE FlexibleInstances #-}
7+{-# LANGUAGE FunctionalDependencies #-}
8+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
9+{-# LANGUAGE LambdaCase #-}
10+{-# LANGUAGE MultiParamTypeClasses #-}
11+{-# LANGUAGE OverloadedStrings #-}
12+{-# LANGUAGE RankNTypes #-}
13+{-# LANGUAGE RecursiveDo #-}
14+{-# LANGUAGE ScopedTypeVariables #-}
15+{-# LANGUAGE StandaloneDeriving #-}
16+{-# LANGUAGE TypeFamilies #-}
17+{-# LANGUAGE UndecidableInstances #-}
18+module Reflex.Vty.Widget
19+ ( VtyWidgetCtx(..)
20+ , VtyWidget(..)
21+ , VtyWidgetOut(..)
22+ , runVtyWidget
23+ , mainWidget
24+ , mainWidgetWithHandle
25+ , HasDisplaySize(..)
26+ , displayWidth
27+ , displayHeight
28+ , HasFocus(..)
29+ , HasVtyInput(..)
30+ , Region(..)
31+ , regionSize
32+ , regionBlankImage
33+ , Drag(..)
34+ , drag
35+ , MouseDown(..)
36+ , MouseUp(..)
37+ , mouseDown
38+ , mouseUp
39+ , pane
40+ , modifyImages
41+ , tellImages
42+ , tellShutdown
43+ , splitV
44+ , splitVDrag
45+ , box
46+ , text
47+ , display
48+ , hyphenBoxStyle
49+ , singleBoxStyle
50+ , roundedBoxStyle
51+ , thickBoxStyle
52+ , doubleBoxStyle
53+ , fill
54+ , hRule
55+ ) where
856
957import Control.Applicative (liftA2)
1058import 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
59+import Control.Monad.Trans (lift)
60+import Control.Monad.Trans.Reader (ReaderT, runReaderT, asks, ask)
61+import Control.Monad.Trans.Writer (WriterT, runWriterT, censor, tell)
62+import Control.Monad.Writer.Adjustable ()
63+import Data.Default (Default(..))
64+import Data.Text (Text)
65+import qualified Data.Text as T
66+import qualified Data.Text.Zipper as TZ
1967import Graphics.Vty (Image)
2068import qualified Graphics.Vty as V
2169import Reflex
22−import Reflex.Class ()
23−import Reflex.Host.Class (MonadReflexCreateTrigger)
70+import Reflex.Class.Switchable
71+import Reflex.NotReady.Class
72+import Reflex.NotReady.Class.Orphans ()
73+
2474import Reflex.Vty.Host
2575
26−-- * Running a vty application
76+-- | The context within which a 'VtyWidget' runs
77+data VtyWidgetCtx t = VtyWidgetCtx
78+ { _vtyWidgetCtx_size :: Dynamic t (Int,Int)
79+ -- ^ The width and height of the region allocated to the widget.
80+ , _vtyWidgetCtx_focus :: Dynamic t Bool
81+ -- ^ Whether the widget should behave as if it has focus for keyboard input.
82+ , _vtyWidgetCtx_input :: Event t VtyEvent
83+ -- ^ User input events that the widget's parent chooses to share. These will generally
84+ -- be filtered for relevance:
85+ -- * Keyboard inputs are restricted to focused widgets
86+ -- * Mouse inputs are restricted to the region in which the widget resides and are
87+ -- translated into its internal coordinates.
88+ }
89+
90+-- | The output of a 'VtyWidget'
91+data VtyWidgetOut t = VtyWidgetOut
92+ { _vtyWidgetOut_images :: Behavior t [Image]
93+ -- ^ The visual output of the 'VtyWidget'
94+ , _vtyWidgetOut_shutdown :: Event t ()
95+ }
96+
97+instance Reflex t => Semigroup (VtyWidgetOut t) where
98+ wo <> wo' = VtyWidgetOut
99+ { _vtyWidgetOut_images = _vtyWidgetOut_images wo <> _vtyWidgetOut_images wo'
100+ , _vtyWidgetOut_shutdown = _vtyWidgetOut_shutdown wo <> _vtyWidgetOut_shutdown wo'
101+ }
102+
103+instance (Reflex t) => Monoid (VtyWidgetOut t) where
104+ mempty = VtyWidgetOut mempty mempty
105+ mappend wo wo' = wo <> wo'
106+
107+instance Reflex t => Switchable t (VtyWidgetOut t) where
108+ switching e0 e = do
109+ shutdown <- switching (_vtyWidgetOut_shutdown e0) $ fmap _vtyWidgetOut_shutdown e
110+ images <- switching (_vtyWidgetOut_images e0) $ fmap _vtyWidgetOut_images e
111+ return $ VtyWidgetOut
112+ { _vtyWidgetOut_images = images
113+ , _vtyWidgetOut_shutdown = shutdown
114+ }
115+
116+-- | A widget that can read its context and produce image output
117+newtype VtyWidget t m a = VtyWidget
118+ { unVtyWidget :: WriterT (VtyWidgetOut t) (ReaderT (VtyWidgetCtx t) m) a
119+ }
120+ deriving (Functor, Applicative, Monad, MonadSample t, MonadHold t, MonadFix, NotReady t)
121+
122+instance (PostBuild t m, Reflex t) => PostBuild t (VtyWidget t m) where
123+ getPostBuild = VtyWidget $ lift getPostBuild
124+
125+instance (Adjustable t m, MonadHold t m, Reflex t) => Adjustable t (VtyWidget t m) where
126+ runWithReplace a0 a' = VtyWidget $ runWithReplace (unVtyWidget a0) $ fmap unVtyWidget a'
127+ traverseIntMapWithKeyWithAdjust f dm0 dm' = VtyWidget $
128+ traverseIntMapWithKeyWithAdjust (\k v -> unVtyWidget (f k v)) dm0 dm'
129+ traverseDMapWithKeyWithAdjust f dm0 dm' = VtyWidget $ do
130+ traverseDMapWithKeyWithAdjust (\k v -> unVtyWidget (f k v)) dm0 dm'
131+ traverseDMapWithKeyWithAdjustWithMove f dm0 dm' = VtyWidget $ do
132+ traverseDMapWithKeyWithAdjustWithMove (\k v -> unVtyWidget (f k v)) dm0 dm'
133+
134+-- | Runs a 'VtyWidget' with a given context
135+runVtyWidget
136+ :: Reflex t
137+ => VtyWidgetCtx t
138+ -> VtyWidget t m a
139+ -> m (a, VtyWidgetOut t)
140+runVtyWidget ctx w = runReaderT (runWriterT (unVtyWidget w)) ctx
27141
28−-- | Sets up the top-level context for a vty widget and runs it with that context
142+-- | Sets up the top-level context for a 'VtyWidget' and runs it with that context
29143mainWidgetWithHandle
30144 :: 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 ()))
145+ -> (forall t m. MonadVtyApp t m => VtyWidget t m ())
40146 -> IO ()
41147mainWidgetWithHandle vty child =
42148 runVtyAppWithHandle vty $ \dr0 inp -> do
@@ -46,178 +152,71 @@ mainWidgetWithHandle vty child =
46152 let inp' = fforMaybe inp $ \case
47153 V.EvResize {} -> Nothing
48154 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
155+ let ctx = VtyWidgetCtx
156+ { _vtyWidgetCtx_size = size
157+ , _vtyWidgetCtx_input = inp'
158+ , _vtyWidgetCtx_focus = constDyn True
159+ }
160+ ((), wo) <- runVtyWidget ctx $ do
161+ tellImages . ffor (current size) $ \(w, h) -> [V.charFill V.defAttr ' ' w h]
162+ child
57163 return $ VtyResult
58− { _vtyResult_picture = fmap (V.picForLayers . reverse) images
59− , _vtyResult_shutdown = shutdown
164+ { _vtyResult_picture = fmap (V.picForLayers . reverse) (_vtyWidgetOut_images wo)
165+ , _vtyResult_shutdown = _vtyWidgetOut_shutdown wo
60166 }
61167
62−-- | The output of a vty widget
63−data VtyWidgetOut t = VtyWidgetOut
64− { _vtyWidgetOut_shutdown :: Event t ()
65− }
66−
67168-- | Like 'mainWidgetWithHandle', but uses a default vty configuration
68169mainWidget
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 ()))
170+ :: (forall t m. MonadVtyApp t m => VtyWidget t m ())
78171 -> IO ()
79172mainWidget child = do
80173 vty <- getDefaultVty
81174 mainWidgetWithHandle vty child
82175
83−-- * Input Events
176+-- | A class for things that know their own display size dimensions
177+class (Reflex t, Monad m) => HasDisplaySize t m | m -> t where
178+ displaySize :: m (Dynamic t (Int, Int))
179+
180+instance (Reflex t, Monad m) => HasDisplaySize t (VtyWidget t m) where
181+ displaySize = VtyWidget . lift $ asks _vtyWidgetCtx_size
182+
183+-- | Retrieve the display width (columns)
184+displayWidth :: HasDisplaySize t m => m (Dynamic t Int)
185+displayWidth = fmap fst <$> displaySize
186+
187+-- | Retrieve the display height (rows)
188+displayHeight :: HasDisplaySize t m => m (Dynamic t Int)
189+displayHeight = fmap snd <$> displaySize
84190
85191-- | A class for things that can receive vty events as input
86−class HasInput t m | m -> t where
192+class HasVtyInput t m | m -> t where
87193 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
180194
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
195+instance (Reflex t, Monad m) => HasVtyInput t (VtyWidget t m) where
196+ input = VtyWidget . lift $ asks _vtyWidgetCtx_input
219197
220−-- * Getting and setting the display region
198+-- | A class for things that can dynamically gain and lose focus
199+class HasFocus t m | m -> t where
200+ focus :: m (Dynamic t Bool)
201+
202+instance (Reflex t, Monad m) => HasFocus t (VtyWidget t m) where
203+ focus = VtyWidget . lift $ asks _vtyWidgetCtx_focus
204+
205+-- | A class for widgets that can produce images to draw to the display
206+class (Reflex t, Monad m) => ImageWriter t m | m -> t where
207+ -- | Send images upstream for rendering
208+ tellImages :: Behavior t [Image] -> m ()
209+
210+instance (Reflex t, Monad m) => ImageWriter t (VtyWidget t m) where
211+ tellImages imgs = VtyWidget $ tell (mempty { _vtyWidgetOut_images = imgs })
212+
213+-- | A class for things that can shut down the vty application
214+class (Reflex t, Monad m) => Shutdown t m where
215+ -- | Signals that the vty application should shut down
216+ tellShutdown :: Event t () -> m ()
217+
218+instance (Reflex t, Monad m) => Shutdown t (VtyWidget t m) where
219+ tellShutdown sd = VtyWidget $ tell (mempty { _vtyWidgetOut_shutdown = sd })
221220
222221-- | A chunk of the display area
223222data Region = Region
@@ -228,293 +227,14 @@ data Region = Region
228227 }
229228 deriving (Show, Read, Eq, Ord)
230229
231−-- | A region that occupies no space.
232−nilRegion :: Region
233−nilRegion = Region 0 0 0 0
234−
235230-- | The width and height of a 'Region'
236231regionSize :: Region -> (Int, Int)
237232regionSize (Region _ _ w h) = (w, h)
238233
239234-- | 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
311− :: (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
318−
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
375− :: (Reflex t, Monad m)
376− => Dynamic t Bool
377− -> FocusReader t m a
378− -> m a
379−runFocusReader b = flip runReaderT b . unFocusReader
380−
381−-- * "Image" output
382−
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
515−
516−
517−-- ** Manipulating images
235+regionBlankImage :: Region -> Image
236+regionBlankImage r@(Region _ _ width height) =
237+ withinImage r $ V.charFill V.defAttr ' ' width height
518238
519239-- | Translates and crops an 'Image' so that it is contained by
520240-- the given 'Region'.
@@ -526,17 +246,7 @@ withinImage (Region left top width height)
526246 | width < 0 || height < 0 = withinImage (Region left top 0 0)
527247 | otherwise = V.translate left top . V.crop width height
528248
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
249+-- | Low-level widget combinator that runs a child 'VtyWidget' within
540250-- a given region and context. This widget filters and modifies the input
541251-- that the child widget receives such that:
542252-- * unfocused widgets receive no key events
@@ -544,18 +254,298 @@ imagesInRegion reg = liftA2 (\r is -> map (withinImage r) is) reg
544254-- * mouse inputs inside the region have their coordinates translated such
545255-- that (0,0) is the top-left corner of the region
546256pane
547− :: (Reflex t, Monad m, HasInput t m, HasImageWriter t m, HasDisplayRegion t m, HasFocusReader t m)
548− => Dynamic t Region
257+ :: (Reflex t, Monad m)
258+ => Dynamic t Region -- ^ Region into which we should draw the widget (in coordinates relative to our own)
549259 -> 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 ()
260+ -> VtyWidget t m a
261+ -> VtyWidget t m a
262+pane reg foc child = VtyWidget $ do
263+ ctx <- lift ask
264+ let ctx' = VtyWidgetCtx
265+ { _vtyWidgetCtx_input = leftmost -- TODO: think about this leftmost more.
266+ [ fmapMaybe id $
267+ attachWith (\(r,f) e -> filterInput r f e)
268+ (liftA2 (,) (current reg) (current foc))
269+ (_vtyWidgetCtx_input ctx)
270+ ]
271+ , _vtyWidgetCtx_focus = liftA2 (&&) (_vtyWidgetCtx_focus ctx) foc
272+ , _vtyWidgetCtx_size = fmap regionSize reg }
273+ (result, wo) <- lift . lift $ runVtyWidget ctx' child
274+ let images = _vtyWidgetOut_images wo
275+ images' = liftA2 (\r is -> map (withinImage r) is) (current reg) images
276+ wo' = wo { _vtyWidgetOut_images = images' }
277+ tell wo'
278+ return result
279+ where
280+ filterInput :: Region -> Bool -> VtyEvent -> Maybe VtyEvent
281+ filterInput (Region l t w h) focused e = case e of
282+ V.EvKey _ _ | not focused -> Nothing
283+ V.EvMouseDown x y btn m -> mouse (\u v -> V.EvMouseDown u v btn m) x y
284+ V.EvMouseUp x y btn -> mouse (\u v -> V.EvMouseUp u v btn) x y
285+ _ -> Just e
286+ where
287+ mouse con x y
288+ | or [ x < l
289+ , y < t
290+ , x >= l + w
291+ , y >= t + h ] = Nothing
292+ | otherwise =
293+ Just (con (x - l) (y - t))
294+
295+-- | Information about a drag operation
296+data Drag = Drag
297+ { _drag_from :: (Int, Int) -- ^ Where the drag began
298+ , _drag_to :: (Int, Int) -- ^ Where the mouse currently is
299+ , _drag_button :: V.Button -- ^ Which mouse button is dragging
300+ , _drag_modifiers :: [V.Modifier] -- ^ What modifiers are held
301+ , _drag_end :: Bool -- ^ Whether the drag ended (the mouse button was released)
302+ }
303+ deriving (Eq, Ord, Show)
304+
305+-- | Converts raw vty mouse drag events into an event stream of 'Drag's
306+drag
307+ :: (Reflex t, MonadFix m, MonadHold t m)
308+ => V.Button
309+ -> VtyWidget t m (Event t Drag)
310+drag btn = do
311+ inp <- input
312+ let f :: Maybe Drag -> V.Event -> Maybe Drag
313+ f Nothing = \case
314+ V.EvMouseDown x y btn' mods
315+ | btn == btn' -> Just $ Drag (x,y) (x,y) btn' mods False
316+ | otherwise -> Nothing
317+ _ -> Nothing
318+ f (Just (Drag from _ _ mods end)) = \case
319+ V.EvMouseDown x y btn' mods'
320+ | end -> Just $ Drag (x,y) (x,y) btn' mods' False
321+ | btn == btn' -> Just $ Drag from (x,y) btn mods' False
322+ | otherwise -> Nothing -- Ignore other buttons.
323+ V.EvMouseUp x y (Just btn')
324+ | end -> Nothing
325+ | btn == btn' -> Just $ Drag from (x,y) btn mods True
326+ | otherwise -> Nothing
327+ V.EvMouseUp x y Nothing -- Terminal doesn't specify mouse up button,
328+ -- assume it's the right one.
329+ | end -> Nothing
330+ | otherwise -> Just $ Drag from (x,y) btn mods True
331+ _ -> Nothing
332+ rec let newDrag = attachWithMaybe f (current dragD) inp
333+ dragD <- holdDyn Nothing $ Just <$> newDrag
334+ return (fmapMaybe id $ updated dragD)
335+
336+-- | Mouse down events for a particular mouse button
337+mouseDown
338+ :: (Reflex t, Monad m)
339+ => V.Button
340+ -> VtyWidget t m (Event t MouseDown)
341+mouseDown btn = do
342+ i <- input
343+ return $ fforMaybe i $ \case
344+ V.EvMouseDown x y btn' mods -> if btn == btn'
345+ then Just $ MouseDown btn' (x, y) mods
346+ else Nothing
347+ _ -> Nothing
348+
349+-- | Mouse up events for a particular mouse button
350+mouseUp
351+ :: (Reflex t, Monad m)
352+ => VtyWidget t m (Event t MouseUp)
353+mouseUp = do
354+ i <- input
355+ return $ fforMaybe i $ \case
356+ V.EvMouseUp x y btn' -> Just $ MouseUp btn' (x, y)
357+ _ -> Nothing
358+
359+-- | Information about a mouse down event
360+data MouseDown = MouseDown
361+ { _mouseDown_button :: V.Button
362+ , _mouseDown_coordinates :: (Int, Int)
363+ , _mouseDown_modifiers :: [V.Modifier]
364+ }
365+ deriving (Eq, Ord, Show)
366+
367+-- | Information about a mouse up event
368+data MouseUp = MouseUp
369+ { _mouseUp_button :: Maybe V.Button
370+ , _mouseUp_coordinates :: (Int, Int)
371+ }
372+ deriving (Eq, Ord, Show)
373+
374+-- | A plain split of the available space into vertically stacked panes.
375+-- No visual separator is built in here.
376+splitV :: (Reflex t, Monad m)
377+ => Dynamic t (Int -> Int)
378+ -- ^ Function used to determine size of first pane based on available size
379+ -> Dynamic t (Bool, Bool)
380+ -- ^ How to focus the two sub-panes, given that we are focused.
381+ -> VtyWidget t m a
382+ -- ^ Widget for first pane
383+ -> VtyWidget t m b
384+ -- ^ Widget for second pane
385+ -> VtyWidget t m (a,b)
386+splitV sizeFunD focD wA wB = do
387+ sz <- displaySize
388+ let regA = (\f (w,h) -> Region 0 0 w (f h)) <$> sizeFunD <*> sz
389+ regB = (\(w,h) (Region _ _ _ hA) -> Region 0 hA w (h - hA)) <$> sz <*> regA
390+ ra <- pane regA (fst <$> focD) wA
391+ rb <- pane regB (snd <$> focD) wB
392+ return (ra,rb)
393+
394+-- | A split of the available space into two parts with a draggable separator.
395+-- Starts with half the space allocated to each, and the first pane has focus.
396+-- Clicking in a pane switches focus.
397+splitVDrag :: (Reflex t, MonadFix m, MonadHold t m)
398+ => VtyWidget t m ()
399+ -> VtyWidget t m a
400+ -> VtyWidget t m b
401+ -> VtyWidget t m (a,b)
402+splitVDrag wS wA wB = do
403+ sz <- displaySize
404+ (_, h0) <- sample $ current sz
405+ dragE <- drag V.BLeft
406+ let splitter0 = h0 `div` 2
407+ rec splitterCheckpoint <- holdDyn splitter0 $ leftmost [fst <$> ffilter snd dragSplitter, resizeSplitter]
408+ splitterPos <- holdDyn splitter0 $ leftmost [fst <$> dragSplitter, resizeSplitter]
409+ splitterFrac <- holdDyn ((1::Double) / 2) $ ffor (attach (current sz) (fst <$> dragSplitter)) $ \((_,h),x) ->
410+ fromIntegral x / fromIntegral h
411+ let dragSplitter = fforMaybe (attach (current splitterCheckpoint) dragE) $
412+ \(splitterY, Drag (_, fromY) (_, toY) _ _ end) ->
413+ if splitterY == fromY then Just (toY, end) else Nothing
414+ regA = (\(w,_) sp -> Region 0 0 w sp) <$> sz <*> splitterPos
415+ regS = (\(w,_) sp -> Region 0 sp w 1) <$> sz <*> splitterPos
416+ regB = (\(w,h) sp -> Region 0 (sp + 1) w (h - sp - 1)) <$> sz <*> splitterPos
417+ resizeSplitter = ffor (attach (current splitterFrac) (updated sz)) $
418+ \(frac, (_,h)) -> round (frac * fromIntegral h)
419+ focA <- holdDyn True $ leftmost
420+ [ True <$ mA
421+ , False <$ mB
422+ ]
423+ (mA, rA) <- pane regA focA $ withMouseDown wA
424+ pane regS (pure False) wS
425+ (mB, rB) <- pane regB (not <$> focA) $ withMouseDown wB
426+ return (rA, rB)
427+ where
428+ withMouseDown x = do
429+ m <- mouseDown V.BLeft
430+ x' <- x
431+ return (m, x')
432+
433+-- | Fill the background with a particular character.
434+fill :: (Reflex t, Monad m) => Char -> VtyWidget t m ()
435+fill c = do
436+ sz <- displaySize
437+ let fillImg = ffor (current sz) $ \(w,h) -> [V.charFill V.defAttr c w h]
438+ tellImages fillImg
439+
440+-- | Fill the background with the bottom
441+hRule :: (Reflex t, Monad m) => BoxStyle -> VtyWidget t m ()
442+hRule boxStyle = fill (_boxStyle_s boxStyle)
443+
444+-- | Transform the images produces by a widget
445+modifyImages
446+ :: (Reflex t, MonadHold t m, MonadFix m)
447+ => Behavior t ([Image] -> [Image])
448+ -> VtyWidget t m a
449+ -> VtyWidget t m a
450+modifyImages f (VtyWidget w) = VtyWidget $ flip censor w $ \wo ->
451+ wo { _vtyWidgetOut_images = f <*> (_vtyWidgetOut_images wo) }
452+
453+-- | Defines a set of symbols to use to draw the outlines of boxes
454+-- C.f. https://en.wikipedia.org/wiki/Box-drawing_character
455+data BoxStyle = BoxStyle
456+ { _boxStyle_nw :: Char
457+ , _boxStyle_n :: Char
458+ , _boxStyle_ne :: Char
459+ , _boxStyle_e :: Char
460+ , _boxStyle_se :: Char
461+ , _boxStyle_s :: Char
462+ , _boxStyle_sw :: Char
463+ , _boxStyle_w :: Char
464+ }
465+
466+instance Default BoxStyle where
467+ def = singleBoxStyle
468+
469+-- | A box style that uses hyphens and pipe characters. Doesn't handle
470+-- corners very well.
471+hyphenBoxStyle :: BoxStyle
472+hyphenBoxStyle = BoxStyle '-' '-' '-' '|' '-' '-' '-' '|'
473+
474+-- | A single line box style
475+singleBoxStyle :: BoxStyle
476+singleBoxStyle = BoxStyle '┌' '─' '┐' '│' '┘' '─' '└' '│'
477+
478+-- | A thick single line box style
479+thickBoxStyle :: BoxStyle
480+thickBoxStyle = BoxStyle '┏' '━' '┓' '┃' '┛' '━' '┗' '┃'
481+
482+-- | A double line box style
483+doubleBoxStyle :: BoxStyle
484+doubleBoxStyle = BoxStyle '╔' '═' '╗' '║' '╝' '═' '╚' '║'
485+
486+-- | A single line box style with rounded corners
487+roundedBoxStyle :: BoxStyle
488+roundedBoxStyle = BoxStyle '╭' '─' '╮' '│' '╯' '─' '╰' '│'
489+
490+-- | Draws a box in the provided style and a child widget inside of that box
491+box :: (Monad m, Reflex t)
492+ => BoxStyle
493+ -> VtyWidget t m a
494+ -> VtyWidget t m a
495+box style child = do
496+ sz <- displaySize
497+ let boxReg = ffor (current sz) $ \(w,h) -> Region 0 0 w h
498+ innerReg = ffor sz $ \(w,h) -> Region 1 1 (w - 2) (h - 2)
499+ tellImages (fmap boxImages boxReg)
500+ tellImages (fmap (\r -> [regionBlankImage r]) (current innerReg))
501+ pane innerReg (pure True) child
502+ where
503+ boxImages :: Region -> [Image]
504+ boxImages (Region left top width height) =
505+ let right = left + width - 1
506+ bottom = top + height - 1
507+ sides =
508+ [ withinImage (Region (left + 1) top (width - 2) 1) $
509+ V.charFill V.defAttr (_boxStyle_n style) (width - 2) 1
510+ , withinImage (Region right (top + 1) 1 (height - 2)) $
511+ V.charFill V.defAttr (_boxStyle_e style) 1 (height - 2)
512+ , withinImage (Region (left + 1) bottom (width - 2) 1) $
513+ V.charFill V.defAttr (_boxStyle_s style) (width - 2) 1
514+ , withinImage (Region left (top + 1) 1 (height - 2)) $
515+ V.charFill V.defAttr (_boxStyle_w style) 1 (height - 2)
516+ ]
517+ corners =
518+ [ withinImage (Region left top 1 1) $
519+ V.char V.defAttr (_boxStyle_nw style)
520+ , withinImage (Region right top 1 1) $
521+ V.char V.defAttr (_boxStyle_ne style)
522+ , withinImage (Region right bottom 1 1) $
523+ V.char V.defAttr (_boxStyle_se style)
524+ , withinImage (Region left bottom 1 1) $
525+ V.char V.defAttr (_boxStyle_sw style)
526+ ]
527+ in sides ++ if width > 1 && height > 1 then corners else []
528+
529+-- | Renders text, wrapped to the container width
530+text
531+ :: (Reflex t, Monad m)
532+ => Behavior t Text
533+ -> VtyWidget t m ()
534+text msg = do
535+ dw <- displayWidth
536+ let img = (\w s -> [wrapText w V.defAttr s]) <$> current dw <*> msg
537+ tellImages img
538+ where
539+ wrapText maxWidth attrs = V.vertCat
540+ . concatMap (fmap (V.string attrs . T.unpack) . TZ.wrapWithOffset maxWidth 0)
541+ . T.split (=='\n')
542+
543+-- | Renders any behavior whose value can be converted to
544+-- 'String' as text
545+display
546+ :: (Reflex t, Monad m, Show a)
547+ => Behavior t a
548+ -> VtyWidget t m ()
549+display a = text $ T.pack . show <$> a
550+
551+