def depsolve (port, level = 2, *known_deps)
	puts "--" * level + "> " + port
	res = []
	my_deps = requires(port)
	new_deps = my_deps - known_deps
	puts "known deps: " + known_deps.join(',')
	puts port + "'s deps: " + my_deps.join(',')
	puts "new deps: " + new_deps.join(',')
	new_deps.each do |dep|
		res = depsolve(dep, level + 2, known_deps | my_deps)
	end
	return res
end