generating json (erlang)

gistfile1.erl

-module(json_fun).

-export([
    test/0
]).

-record(my_api, {
    name,
    age,
    cars
}).

-record(car, {
    name,
    year
}).

%% public
test() ->
    my_api_json(#my_api {
      name = <<"LP">>,
      age = 28,
      cars = [
          #car {
              name = <<"Toyota">>,
              year = <<"2014">>
          },
          #car {
              name = <<"Lexus">>
          }
      ]
    }).

%% private
my_api_json(#my_api {} = MyApi) ->
    jiffy:encode({zip(record_info(fields, my_api), tl(tuple_to_list(MyApi)))}).

car_json(#car {} = Car) ->
    jiffy:encode({zip(record_info(fields, car), tl(tuple_to_list(Car)))}).

zip([], []) -> [];
zip([_ | T], [undefined | T2]) -> zip(T, T2);
zip([cars | T], [Cars | T2]) ->
    [{cars, [car_json(Car) || Car <- Cars]} | zip(T, T2)];
zip([H | T], [H2 | T2]) ->
    [{atom_to_binary(H, utf8), H2} | zip(T, T2)].

json_fun:test().
<<"{"name":"LP","age":28,"cars":["{\"name\":\"Toyota\",\"year\":\"2014\"}","{\"name\":\"Lexus\"}"]}">>