partition_impl : pure (list:@T, pivot:T, ret:(2$@T))->(2$@T) =
    return ret if !list;
    (h,t) = *list;
    if h < pivot ?
        return partition_impl( t, pivot, ( [0]ret::h, [1]ret ) );
    else ?
        return partition_impl( t, pivot, ( [0]ret, [1]ret::h ) );
    .
.
partition : pure (list:@T, pivot:T)->(2$@T) =
    return partition_impl( list, pivot, (2$[]) );
.

quick_sort : pure (list:@T)->(@T) =
    if !list ? return list;.
    (h,t) = *list;
    if !t ? return list;.
    (pre,post) = partition(t, h);
    if !pre ? return h::quicksort(post);
    else if !post ? return quicksort(pre)::h;
    else return quicksort(pre)::h::quicksort(post);
    .
.

(14:22:41) pfeilspitze> I wrote up quick, insertion, selection, and merge sorts before starting on the interpreter
(14:23:08) pfeilspitze> they've gone through a number of revisions as I adapt the syntax
(14:23:41) pfeilspitze> for parsing ease, grammar simplification, and typing convenience
(14:24:33) pfeilspitze> I was originally using index@tuple for the get-nth-element syntax
(14:24:43) pfeilspitze> but it turned out to be really annoying to type
(14:25:00) pfeilspitze> yeah, and I need to get off to circuit analysis class