module Exercise_5 where
import Data.Maybe

{- Library -- nicht verändern! -}

type State = Integer
type DA = (State, State -> Char -> State, State -> Bool)
type ListDA = (State, [((State, Char), State)], [State])

a :: DA
a = (0, delta, (==1))
  where
    delta 0 'a' = 1
    delta 1 'a' = 1
    delta 2 'a' = 1
    delta 0 'b' = 2
    delta 1 'b' = 2
    delta 2 'b' = 2

toDA :: ListDA -> DA
toDA (start, delta, final) = (start, deltaFun delta, (`elem` final))
  where deltaFun dl = curry (fromMaybe 0 . flip lookup dl)


{- H1 -}

fixpoint :: (a -> a -> Bool) -> (a -> a) -> a -> a
fixpoint = undefined

cents :: [Integer] -> [Integer]
cents = undefined

trancl :: [(Integer, Integer)] -> [(Integer, Integer)]
trancl = undefined

{- H2 -}

advance :: DA -> State -> String -> State
advance = undefined

prop_advance_empty :: DA -> State -> Bool
prop_advance_empty = undefined

prop_advance_single :: DA -> State -> Char -> Bool
prop_advance_single = undefined

prop_advance_concat :: DA -> State -> String -> String -> Bool
prop_advance_concat = undefined

accept :: DA -> String -> Bool
accept = undefined

reachableStates :: DA -> State -> [Char] -> [State]
reachableStates = undefined


{- H3 -}

{-WETT-}
quasiSubseq :: Eq a => [a] -> [a] -> Bool
quasiSubseq xs ys = undefined
{-TTEW-}