Rearranging variable_names

avs_term_rearranged(AVs, T, AVsR) :-
    term_variables(T, Vs),
    copy_term(Vs+AVs, Vs1+AVs1),
    bind_names(AVs1),
    build_vn_list(Vs, Vs1, AVsR).

bind_names([]).
bind_names([N=V|AVs]) :-
    N = V,
    bind_names(AVs).

build_vn_list([], [], []).
build_vn_list([V|Vs],[N|Ns],NVs) :-
    ( atom(N) ->
      NVs = [N=V|NVs1]
    ; var(N) ->
      NVs = NVs1
    ),
    build_vn_list(Vs, Ns, NVs1).