brick/programs/SuspendAndResumeDemo.hs

63 lines
1.4 KiB
Haskell

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TemplateHaskell #-}
module Main where
import Control.Lens (makeLenses, (.~), (^.), (&))
import Control.Monad (void)
import Data.Monoid
import Data.Default
import qualified Graphics.Vty as V
import Brick.Main
( App(..), neverShowCursor, defaultMain
, suspendAndResume, halt, continue
, EventM, Next
)
import Brick.Widgets.Core
( Widget
, vBox
, str
)
data St =
St { _stExternalInput :: String
}
makeLenses ''St
drawUI :: St -> [Widget]
drawUI st = [ui]
where
ui = vBox [ str $ "External input: \"" <> st^.stExternalInput <> "\""
, "(Press Esc to quit or Space to ask for input)"
]
appEvent :: St -> V.Event -> EventM (Next St)
appEvent st e =
case e of
V.EvKey V.KEsc [] -> halt st
V.EvKey (V.KChar ' ') [] -> suspendAndResume $ do
putStrLn "Suspended. Please enter something and press enter to resume:"
s <- getLine
return $ st & stExternalInput .~ s
_ -> continue st
initialState :: St
initialState =
St { _stExternalInput = ""
}
theApp :: App St V.Event
theApp =
App { appDraw = drawUI
, appChooseCursor = neverShowCursor
, appHandleEvent = appEvent
, appStartEvent = return
, appAttrMap = const def
, appLiftVtyEvent = id
}
main :: IO ()
main = do
void $ defaultMain theApp initialState