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https://github.com/jtdaugherty/brick.git
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This change makes it possible for brick to extent the event space using its own event notions in addition those provided by Vty and the application itself. This means we no longer need the user to provide the type and appLiftVtyEvent went away. This makes pattern-matching in event handlers a little noisier with the benefit that we can now add events like mouse clicks or drags to the event type.
100 lines
3.0 KiB
Haskell
100 lines
3.0 KiB
Haskell
{-# LANGUAGE OverloadedStrings #-}
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module Main where
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import Lens.Micro ((^.))
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import Control.Monad (void)
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import Data.Monoid
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import Data.Maybe (fromMaybe)
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import qualified Graphics.Vty as V
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import qualified Brick.Main as M
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import qualified Brick.Types as T
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import qualified Brick.Widgets.Border as B
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import qualified Brick.Widgets.List as L
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import qualified Brick.Widgets.Center as C
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import qualified Brick.AttrMap as A
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import qualified Data.Vector as Vec
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import Brick.Types
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( Widget
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)
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import Brick.Widgets.Core
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( (<+>)
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, str
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, vLimit
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, hLimit
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, vBox
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, withAttr
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)
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import Brick.Util (fg, on)
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drawUI :: (Show a) => L.List () a -> [Widget ()]
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drawUI l = [ui]
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where
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label = str "Item " <+> cur <+> str " of " <+> total
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cur = case l^.(L.listSelectedL) of
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Nothing -> str "-"
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Just i -> str (show (i + 1))
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total = str $ show $ Vec.length $ l^.(L.listElementsL)
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box = B.borderWithLabel label $
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hLimit 25 $
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vLimit 15 $
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L.renderList listDrawElement True l
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ui = C.vCenter $ vBox [ C.hCenter box
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, str " "
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, C.hCenter $ str "Press +/- to add/remove list elements."
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, C.hCenter $ str "Press Esc to exit."
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]
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appEvent :: L.List () Char -> T.BrickEvent () e -> T.EventM () (T.Next (L.List () Char))
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appEvent l (T.VtyEvent e) =
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case e of
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V.EvKey (V.KChar '+') [] ->
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let el = nextElement (L.listElements l)
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pos = Vec.length $ l^.(L.listElementsL)
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in M.continue $ L.listInsert pos el l
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V.EvKey (V.KChar '-') [] ->
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case l^.(L.listSelectedL) of
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Nothing -> M.continue l
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Just i -> M.continue $ L.listRemove i l
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V.EvKey V.KEsc [] -> M.halt l
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ev -> M.continue =<< L.handleListEvent ev l
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where
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nextElement :: Vec.Vector Char -> Char
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nextElement v = fromMaybe '?' $ Vec.find (flip Vec.notElem v) (Vec.fromList ['a' .. 'z'])
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appEvent l _ = M.continue l
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listDrawElement :: (Show a) => Bool -> a -> Widget ()
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listDrawElement sel a =
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let selStr s = if sel
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then withAttr customAttr (str $ "<" <> s <> ">")
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else str s
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in C.hCenter $ str "Item " <+> (selStr $ show a)
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initialState :: L.List () Char
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initialState = L.list () (Vec.fromList ['a','b','c']) 1
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customAttr :: A.AttrName
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customAttr = L.listSelectedAttr <> "custom"
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theMap :: A.AttrMap
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theMap = A.attrMap V.defAttr
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[ (L.listAttr, V.white `on` V.blue)
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, (L.listSelectedAttr, V.blue `on` V.white)
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, (customAttr, fg V.cyan)
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]
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theApp :: M.App (L.List () Char) e ()
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theApp =
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M.App { M.appDraw = drawUI
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, M.appChooseCursor = M.showFirstCursor
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, M.appHandleEvent = appEvent
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, M.appStartEvent = return
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, M.appAttrMap = const theMap
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}
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main :: IO ()
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main = void $ M.defaultMain theApp initialState
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