dynset

[fp1415.git] / fp2 / week3 / camil / StdDynSet.icl

diff --git a/fp2/week3/camil/StdDynSet.icl b/fp2/week3/camil/StdDynSet.icl
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+++ b/fp2/week3/camil/StdDynSet.icl
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+implementation module StdDynSet
+
+import StdEnv
+import StdMaybe
+import StdDynamic
+
+fromDynamic :: Dynamic -> Maybe t | TC t
+fromDynamic (x :: t^) = Just x
+fromDynamic other = Nothing
+
+isEqual:: Dynamic t -> Bool | Set t
+isEqual (x :: t^) a = x == a
+isEqual _ _ = False
+
+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 == a b = nrOfElts a == nrOfElts b && isSubset a b
+
+toSet :: a -> Set | Set, == a
+toSet e = Set [dynamic e]
+
+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 :: a^):xs]) = x == y || memberOfSet x (Set xs)
+memberOfSet x (Set [y:xs]) = memberOfSet x (Set xs)
+
+dynMemberOfSet :: Dynamic Set -> Bool
+dynMemberOfSet _ (Set []) = False
+dynMemberOfSet x (Set [y:xs]) = isEqual x (fromJust(fromDynamic y)) || dynMemberOfSet x (Set xs)
+//dynMemberOfSet x (Set [y:xs]) = memberOfSet x (Set xs)
+
+isSubset :: Set Set -> Bool
+isSubset a b = (nrOfElts a) == (nrOfElts (intersection a b))
+
+isStrictSubset :: Set Set -> Bool
+isStrictSubset a b = abort "isStrictSubset nog niet geimplementeerd.\n"
+
+union :: Set Set -> Set
+union (Set a) (Set b) = Set (a ++ b)
+
+intersection :: Set Set -> Set
+intersection (Set []) bs = bs
+intersection as (Set []) = as
+intersection (Set [a:as]) (Set [(b::t):bs]) = Set [a \\ a <- as | not (dynMemberOfSet a (Set bs))]
+
+without :: Set Set -> Set
+without a b = abort "without nog niet geimplementeerd.\n"
+
+//Start :: Set
+Start = memberOfSet 2 (toSet 1)