fp2/week3/camil/StdDynSet.icl

   1 implementation module StdDynSet
   2
   3 import StdEnv
   4 import StdMaybe
   5 import StdDynamic
   6
   7 fromDynamic :: Dynamic -> Maybe t | TC t
   8 fromDynamic (x :: t^) = Just x
   9 fromDynamic other = Nothing
  10
  11 isEqual:: Dynamic t -> Bool | Set t
  12 isEqual (x :: t^) a = x == a
  13 isEqual _ _ = False
  14
  15 //isEqual`:: Dynamic Dynamic -> Bool | Set t
  16 //isEqual` (x :: t^) (y :: t^) = x == y
  17 //isEqual` _ _ = False
  18
  19 isEqual`` :: Dynamic Dynamic -> Bool
  20 isEqual`` x y = (fromJust(fromDynamic x)) == (fromJust(fromDynamic y))
  21
  22 class Set a | TC, ==, toString a
  23
  24 :: Set = Set [Dynamic]
  25
  26 instance zero     Set
  27 where zero = Set []
  28
  29 instance toString Set
  30 where toString (Set a) = abort "toString not implemented"
  31
  32 instance == Set
  33 where == a b = nrOfElts a == nrOfElts b && isSubset a b
  34
  35 toSet :: a -> Set | Set, == a
  36 toSet e = Set [dynamic e]
  37
  38 nrOfElts :: Set -> Int
  39 nrOfElts (Set a) = length a
  40
  41 isEmptySet :: Set -> Bool
  42 isEmptySet (Set []) = True
  43 isEmptySet _ = False
  44
  45 memberOfSet :: a Set -> Bool | Set, == a
  46 memberOfSet _ (Set []) = False
  47 memberOfSet x (Set [(y :: a^):xs]) = x == y || memberOfSet x (Set xs)
  48 memberOfSet x (Set [y:xs]) = memberOfSet x (Set xs)
  49
  50 dynMemberOfSet :: Dynamic Set -> Bool
  51 dynMemberOfSet _ (Set []) = False
  52 dynMemberOfSet x (Set [y:xs]) = isEqual x (fromJust(fromDynamic y)) || dynMemberOfSet x (Set xs)
  53 //dynMemberOfSet x (Set [y:xs]) = memberOfSet x (Set xs)
  54
  55 isSubset :: Set Set -> Bool
  56 isSubset a b = (nrOfElts a) == (nrOfElts (intersection a b))
  57
  58 isStrictSubset :: Set Set -> Bool
  59 isStrictSubset a b = abort "isStrictSubset nog niet geimplementeerd.\n"
  60
  61 union :: Set Set -> Set
  62 union (Set a) (Set b) = Set (a ++ b)
  63
  64 intersection :: Set Set -> Set
  65 intersection (Set []) bs = bs
  66 intersection as (Set []) = as
  67 intersection (Set [a:as]) (Set bs) = Set [a \\ a <- as | not (dynMemberOfSet a (Set bs))]
  68
  69 without :: Set Set -> Set
  70 without a b = abort "without nog niet geimplementeerd.\n"
  71
  72 //Start :: Set
  73 Start = memberOfSet 2 (toSet 1)