implementation module StdSortList

import StdEnv

::  SortList a :== [a]

newSortList   :: (SortList a)
newSortList = []

memberSort    :: a (SortList a) -> Bool       | Eq, Ord a      // is element van
memberSort _ [] = False
memberSort m l
    | hd l == m = True
    | hd l > m = False
    | otherwise = memberSort m (tl l)

insertSort    :: a (SortList a) -> SortList a | Ord a          // voeg element toe
insertSort m l = insertSort` newSortList m l 
where 
    insertSort` :: (SortList a) a (SortList a) -> (SortList a) | Ord a
    insertSort` l1 m l2
        | count l2 == 0 = l1 ++ [m]
        | minimum l2 >= m = l1 ++ [m] ++ l2
        | otherwise = insertSort` (l1 ++ [hd l2]) m (tl l2)

removeFirst   :: a (SortList a) -> SortList a | Eq, Ord a      // verwijder eerste voorkomen
removeFirst m l = removeFirst` newSortList m l
where
    removeFirst` :: (SortList a) a (SortList a) -> (SortList a) | Eq, Ord a
    removeFirst` l1 m l2
        | count l2 == 0 = l1
        | minimum l2 > m = l1 ++ l2
        | minimum l2 == m = l1 ++ tl l2
        | otherwise = removeFirst` (l1 ++ [hd l2]) m (tl l2)

removeAll     :: a (SortList a) -> SortList a | Eq, Ord a      // verwijder alle voorkomens
removeAll m l = removeAll` newSortList m l
where
    removeAll` :: (SortList a) a (SortList a) -> (SortList a) | Eq, Ord a
    removeAll` l1 m l2
        | count l2 == 0 = l1
        | minimum l2 > m = l1 ++ l2
        | minimum l2 == m = removeAll` l1 m (tl l2)
        | otherwise = removeAll` (l1 ++ [hd l2]) m (tl l2)

elements      ::   (SortList a) -> [a]                         // geef alle elementen
elements l = l

count         ::   (SortList a) -> Int                         // aantal elementen
count l = length l

minimum       ::   (SortList a) -> a                           // huidige minimum waarde
minimum l = hd l

maximum       ::   (SortList a) -> a                           // huidige maximum waarde
maximum l = last l

mergeSortList :: (SortList a) (SortList a) -> SortList a | Eq, Ord a // meng gesorteerde lijsten
mergeSortList l1 [] = l1
mergeSortList l1 l2 = mergeSortList (insertSort (hd l2) l1) (tl l2)