Bubblesort in Erlang

It's amazing how if a language isn't a part of your daily work, how rusty you get at it. Oh erlang, how I didn't mean to neglect you! I finally convinced Ian to give Erlang a shot, and he's been going through Joe Armstrong's book. He decided to write bubblesort, and it took him hours. This is what he had to say:

I'm having some difficulty
getting used to the idea of a language where every variable is a const.
its interesting, though.

but I have to admit the one line erlang quicksort is one of the
prettiest code snippits I've ever seen.

but "=:=" for equivalence? a three character long operator? who do
they think they are?

I wrote bubble sort and merge sort in erlang last night. it took
hours. the code looks horrible. for the first time since learning
basic in high school I feel like a foreigner in a strange land. its
invigorating.

actually I find it a bit intimidating. when something takes more than a
few lines of code I wonder if I'm doing it wrong. if joe armstrong ever
saw my bubble sort he'd probably take my book away.

I decided to give it a shot. It's certainly a far better exercise than FizzBuzz. Given that I had written a neural network in erlang before, I figured I'd be more than ok with bubblesort. Right?

Wrong.

It's taken an embarrassingly long time to get it right, plus, I took a shortcut that isn't very optimal. If I ever had to write this in an interview in Erlang, They'd take my keyboard away. Here's what I came up with:

-module(bubblesort).
-export([sort/1]).

sort([First | Rest]) ->
    sort_helper([First | Rest], swap(First, Rest)).

sort_helper(List, New_list) when List =:= New_list ->
    List;
sort_helper(List, [First | Rest]) ->
    sort_helper([First | Rest], swap(First, Rest)).

swap(Current, []) ->
    [Current];
swap(Current, [First | Rest]) when Current =< First ->
    [Current] ++ swap(First, Rest);
swap(Current, [First | Rest]) ->
    [First] ++ swap(Current, Rest).

Notice that I use the guard "List =:= New_list" to determine if a swap took place. In a large list, this would add n comparisons on every pass. Horrible. But since it's an exercise, I neglected to keep track of swaps.

More than half the time was wrestling with the syntax. I had forgotten a lot of it, and mixed up [First, Rest] with [First | Rest], and I kept forgetting that I needed to prefix the functions by their module names. It's bubblesort:swap(...) when you want to call it, and I was scratching my head for 10 mins. But the other time was just thinking recursively. Unless you're working in a language the heavily uses recursive to iteration, you don't often use it. But defn I prefer recursive as it's much more succinct. Can anyone come up with a one-liner Bubblesort?

For reference, "the one liner" quicksort Ian was talking about:

qsort([]) -> 
    [];
qsort([Pivot | T]) ->
    qsort([X || X <- T, X < Pivot]) ++ [Pivot] ++ qsort([X || X <- T, X >= Pivot]).