brick/programs/AttrDemo.hs
Jonathan Daugherty bd89f787d2 Support GHC 8.4 (fixes #162)
This change splits up Monoid instances into Monoid and Semigroup. It
also conditionally imports Data.Monoid on GHCs prior to 8.4.
2018-03-17 09:03:59 -07:00

80 lines
2.5 KiB
Haskell

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE CPP #-}
module Main where
#if !(MIN_VERSION_base(4,11,0))
import Data.Monoid
#endif
import Graphics.Vty
( Attr, white, blue, cyan, green, red, yellow
, black, withURL
)
import Brick.Main
import Brick.Types
( Widget
)
import Brick.Widgets.Core
( (<=>)
, withAttr
, vBox
, str
, hyperlink
, modifyDefAttr
)
import Brick.Util (on, fg)
import Brick.AttrMap (attrMap, AttrMap)
ui :: Widget n
ui =
vBox [ str "This text uses the global default attribute."
, withAttr "foundFull" $
str "Specifying an attribute name means we look it up in the attribute tree."
, (withAttr "foundFgOnly" $
str ("When we find a value, we merge it with its parent in the attribute")
<=> str "name tree all the way to the root (the global default).")
, withAttr "missing" $
str "A missing attribute name just resumes the search at its parent."
, withAttr ("general" <> "specific") $
str "In this way we build complete attribute values by using an inheritance scheme."
, withAttr "foundFull" $
str "You can override everything ..."
, withAttr "foundFgOnly" $
str "... or only what you want to change and inherit the rest."
, str "Attribute names are assembled with the Monoid append operation to indicate"
, str "hierarchy levels, e.g. \"window\" <> \"title\"."
, str " "
, withAttr "linked" $
str "This text is hyperlinked in terminals that support hyperlinking."
, str " "
, hyperlink "http://www.google.com/" $
str "This text is also hyperlinked in terminals that support hyperlinking."
, str " "
, modifyDefAttr (`withURL` "http://www.google.com/") $
str "This text is hyperlinked by modifying the default attribute."
]
globalDefault :: Attr
globalDefault = white `on` blue
theMap :: AttrMap
theMap = attrMap globalDefault
[ ("foundFull", white `on` green)
, ("foundFgOnly", fg red)
, ("general", yellow `on` black)
, ("general" <> "specific", fg cyan)
, ("linked", fg yellow `withURL` "http://www.google.com/")
]
app :: App () e ()
app =
App { appDraw = const [ui]
, appHandleEvent = resizeOrQuit
, appStartEvent = return
, appAttrMap = const theMap
, appChooseCursor = neverShowCursor
}
main :: IO ()
main = defaultMain app ()