kempe-0.2.0.5: lib/maybe.kmp

type Maybe a { Just a | Nothing }

fromMaybe : a (Maybe a) -- a
          =: [
    { case
        | Just    -> dip(drop)
        | Nothing ->
    }
]

isJust : (Maybe a) -- Bool
       =: [
    { case
        | Just -> drop True
        | Nothing -> False
    }
]

isNothing : (Maybe a) -- Bool
          =: [
    { case
        | Nothing -> True
        | Just -> drop False
    }
]