, deleteMax
, deleteFindMin
, deleteFindMax
+ , maxView
+ , minView
-- * Conversion
Bin _ x l r -> let (xm,r') = deleteFindMax r in (xm,balance x l r')
Tip -> (error "Set.deleteFindMax: can not return the maximal element of an empty set", Tip)
+-- | /O(log n)/. Retrieves the minimal key of the set, and the set stripped from that element
+-- @fail@s (in the monad) when passed an empty set.
+minView :: Monad m => Set a -> m (Set a, a)
+minView Tip = fail "Set.minView: empty set"
+minView x = return (swap $ deleteFindMin x)
+
+-- | /O(log n)/. Retrieves the maximal key of the set, and the set stripped from that element
+-- @fail@s (in the monad) when passed an empty set.
+maxView :: Monad m => Set a -> m (Set a, a)
+maxView Tip = fail "Set.maxView: empty set"
+maxView x = return (swap $ deleteFindMax x)
+
+swap (a,b) = (b,a)
+
+
{--------------------------------------------------------------------
[balance x l r] balances two trees with value x.