module NSWTopo::Zip

def zip(directory, archive)
  Enumerator.new do |yielder|
    yielder << ->(dir) { OS.zip "-r", archive.expand_path, *Pathname.glob('*') }
    yielder << ->(dir) { OS.send "7z", "a", "-tzip", "-r", archive.expand_path, *Pathname.glob('*') }
    raise "no zip utility installed"
  end.each do |zip|
    Dir.chdir(directory, &zip)
    break
  rescue OS::Missing
  end
end