1 module DisplayOptions where

2

3 import Data.List ((\\))

4

5 type ShowInfo = [What]

6 data What = NodeLabel | NodeInfo | EdgeLabel | EdgeInfo deriving (Eq)

7

8 data DisplayOptions = DP

9 { dpShowInfo :: ShowInfo

10 }

11

12 standard :: DisplayOptions

13 standard = DP []

14

15 toggle :: What -> DisplayOptions -> DisplayOptions

16 toggle w (DP opts) = DP (if w `elem` opts then opts\\[w] else w:opts)