import code from "readLine.o"
+//Maybe
+isNothing :: !(Maybe .x) -> Bool
+isNothing Nothing = True
+isNothing _ = False
+
+isJust :: !(Maybe .x) -> Bool
+isJust Nothing = False
+isJust _ = True
+
+fromJust :: !(Maybe .x) -> .x
+fromJust (Just x) = x
+
instance toString HistoryItem where
toString {line,timestamp} = line +++ " (" +++ timestamp +++ ")"
instance toString HistoryState where