Ruby YAML and sorting top-level keys

I wanted to sort the top-level keys in a YAML hash in Ruby in a once-off way (that is, not sort all the time - just this once). I found two methods.

The first one is based on something I found on StackOverflow. So given a hash:

a = { 
  "a" => "b",
  "e" => "b",
  "c" => "b",
  "p" => "b",
  "z" => "b",
  "x" => "b",
  "d" => "b",
}

The function looks something like:

def sort_yaml1(obj)
  YAML::quick_emit(obj) do |out|
    out.map(obj.taguri, obj.to_yaml_style) do |map|
      obj.keys.sort.each do |k| 
        v = obj[k]
        map.add(k, v)
      end 
    end 
  end 
end

puts sort_yaml1(a)

The second methodology is very manual and not quite as elegant, but is probably less dependant on the YAML internals:

def sort_yaml2(obj)
  arr = obj.sort
  out = "---\n"
  arr.each do |element|
    entry = {element[0] => element[1]}
    out += entry.to_yaml.to_a[1..-1].join + "\n"
  end 
  out 
end

puts sort_yaml2(a)

Its a shame the SortedKeys option isn't supported out of the box in Ruby 1.8.7, but it seems the SortedKeys option isn't passed to the underlying syck driver at all.