module DisplayOptions where

import Data.List ((\\))

type ShowInfo = [What]
data What     = NodeLabel | NodeInfo | EdgeLabel | EdgeInfo	deriving (Eq)

data DisplayOptions = DP
	{ dpShowInfo :: ShowInfo
	}

standard :: DisplayOptions
standard = DP []

toggle :: What -> DisplayOptions -> DisplayOptions
toggle w (DP opts) = DP (if w `elem` opts then opts\\[w] else w:opts)