private fun search_recursive(node: BKNode, res: Array[BKMatch], key: String, tolerance: Int) do
		var dist = node.key.levenshtein_distance(key)
		var min = dist - tolerance
		var max = dist + tolerance

		if dist < tolerance then
			res.add new BKMatch(dist, node.key)
		end

		for odist, child in node do
			if odist < min or odist > max then continue
			search_recursive(child, res, key, tolerance)
		end
	end