brick/programs/AttrDemo.hs
Jonathan Daugherty 6f1b62ae53 AttrName: remove IsString instance
This change is motivated by the API wart that results from the
overloading of both "<>" and string literals that resulted in code like
this:

  a :: AttrName
  a = "blah" <> "things"

While this worked to create an AttrName with two segments, it is far too
easy to read this as two strings concatenated. The overloading hides
what is really going on with the segments of the attribute name. The way
to write the above example after this change is:

  a :: AttrName
  a = attrName "blah" <> attrName "things"
2022-08-04 18:44:57 -07:00

81 lines
2.7 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, attrName)
ui :: Widget n
ui =
vBox [ str "This text uses the global default attribute."
, withAttr (attrName "foundFull") $
str "Specifying an attribute name means we look it up in the attribute tree."
, (withAttr (attrName "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 (attrName "missing") $
str "A missing attribute name just resumes the search at its parent."
, withAttr (attrName "general" <> attrName "specific") $
str "In this way we build complete attribute values by using an inheritance scheme."
, withAttr (attrName "foundFull") $
str "You can override everything ..."
, withAttr (attrName "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 (attrName "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
[ (attrName "foundFull", white `on` green)
, (attrName "foundFgOnly", fg red)
, (attrName "general", yellow `on` black)
, (attrName "general" <> attrName "specific",
fg cyan)
, (attrName "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 ()