implementation module StdDynSet

import StdEnv
import StdDynamic

class Set a | TC, ==, toString a

:: Set = Set [Dynamic]

instance zero     Set
where zero = Set []

instance toString Set
where toString (Set a) = abort "toString not implemented"
	
instance == Set
where 
	(==) (Set []) (Set []) = True
	(==) (Set []) _ = False
	(==) _ (Set []) = False

toSet :: a -> Set | Set a
toSet a = Set [dynamic a]

nrOfElts :: Set -> Int
nrOfElts (Set a) = length a

isEmptySet :: Set -> Bool
isEmptySet (Set []) = True
isEmptySet _ = False

memberOfSet :: a Set -> Bool | Set a
memberOfSet _ (Set []) = False
memberOfSet x (Set [y:xs])
| isEqual x y = True
| otherwise = memberOfSet x xs

isSubset :: Set Set -> Bool
isSubset a b = abort "isSubset nog niet geimplementeerd.\n"

isStrictSubset :: Set Set -> Bool
isStrictSubset a b = abort "isStrictSubset nog niet geimplementeerd.\n"

union :: Set Set -> Set
union a b = abort "union nog niet geimplementeerd.\n"

intersection :: Set Set -> Set
intersection a b = abort "intersection nog niet geimplementeerd.\n"

without :: Set Set -> Set
without a b = abort "without nog niet geimplementeerd.\n"

Start :: Set
Start = toSet 1