semantic/app/Console.hs

module Console where

import Data.Char

data Colour = Black | Red | Green | Yellow | Blue | Purple | Cyan | White
  deriving Bounded

instance Enum Colour where
  fromEnum Black = 30
  fromEnum Red = 31
  fromEnum Green = 32
  fromEnum Yellow = 33
  fromEnum Blue = 34
  fromEnum Purple = 35
  fromEnum Cyan = 36
  fromEnum White = 37

  toEnum 30 = Black
  toEnum 31 = Red
  toEnum 32 = Green
  toEnum 33 = Yellow
  toEnum 34 = Blue
  toEnum 35 = Purple
  toEnum 36 = Cyan
  toEnum 37 = White
  toEnum _ = error "unknown colour code"

data Style = Normal | Bold | Underline
  deriving Bounded

instance Enum Style where
  fromEnum Normal = 0
  fromEnum Bold = 1
  fromEnum Underline = 4

  toEnum 0 = Normal
  toEnum 1 = Bold
  toEnum 4 = Underline

data Attribute = Attribute { colour :: Colour, style :: Style }

applyAttribute :: Attribute -> String -> String
applyAttribute attribute string = "\x001b[" ++ [ chr . fromEnum $ style attribute ] ++ ";" ++ [ chr . fromEnum $ colour attribute ] ++ "m" ++ string ++ "\x001b[0m"