Basic.hs

{-# LANGUAGE TypeSynonymInstances, FlexibleInstances #-}

module IHaskell.Display.Basic () where

import           IHaskell.Display

import           Text.Printf

instance Show a => IHaskellDisplay (Maybe a) where
  display just = return $ Display [stringDisplay, htmlDisplay]
    where
      stringDisplay = plain (show just)
      htmlDisplay = html str
      str =
        case just of
          Nothing -> "<span style='color: red; font-weight: bold;'>Nothing</span>"
          Just x -> printf
                      "<span style='color: green; font-weight: bold;'>Just</span><span style='font-family: monospace;'>%s</span>"
                      (show x)