# A FlowSet based on a HashSet.
class FlowHashSet[E]
	super FlowSet
	super HashSet[E]

	redef fun clone do return new FlowHashSet[E].from(self)

	# Remove all items found in `other` from `self`.
	fun remove_from(other: Collection[E]) do
		for e in other do remove(e)
	end

	redef fun flow_union(o) do return new FlowHashSet[E].from(union(o))
end