define comb(n, m);
    lvars ress = [];
    define do_combs(l, m, el_lst);
        lvars i;
        if m = 0 then
            cons(rev(el_lst), ress) -> ress;
        else
            for i from l to n - m do
                do_combs(i + 1, m - 1, cons(i, el_lst));
            endfor;
        endif;
    enddefine;
    do_combs(0, m, []);
    rev(ress);
enddefine;

comb(5, 3) ==>