Order items according to another sorted array

erlang-sort.erl

-spec sort([integer()], [integer()]) -> {[integer()], [integer()]}.
sort([], _)              -> {[], [0]};
sort(Stack, Stack)       -> {Stack, [0]};
sort(Stack=[H|_], Order) ->
    Length = length(Stack),
    Last = lists:last(Stack),
    Ops = case lists:max(Stack) of
      	      H    -> [Length];
      	      Last -> [];
	      Max  -> [position(Max, Stack), Length]
	  end,
    {NewStack, CompletedOps} = flip(Ops, Stack),
    sort(Length - 1, NewStack, Order, CompletedOps).

-spec sort(integer(), [integer()],  [integer()],  [integer()]) -> { [integer()],  [integer()]}.
sort(_, [], _, Ops)           -> {[], Ops};
sort(1, Stack, _, Ops)        -> {Stack, Ops};
sort(_, Stack, Stack, Ops)    -> {Stack, [0|Ops]};
sort(Iter, Stack, Order, Ops) -> 
    {NewStack, CompletedOps} = flip([position(Iter, Stack), Iter], Stack, Ops),
    sort(Iter - 1, NewStack, Order, CompletedOps).  

ruby-sort.rb

order = [3, 1, 2, 4, 5, 7, 6]
items = [{id: 1}, {id: 2}, {id: 3}, {id: 4}, {id: 5}, {id: 6}, {id: 7}]

order.map do |id|
  items.find { |item| item[:id] == id }
end