%%%----------------------------------------------------------------------------
-module(hope_kv_list).
--behavior(hope_dictionary).
+-behavior(hope_gen_dictionary).
-export_type(
[ t/2
, fold/3
, of_kv_list/1
, to_kv_list/1
+ , validate_unique_presence/2 % Assume default optional parameter(s)
+ , validate_unique_presence/3 % Specify optional parameter(s)
]).
-type t(K, V) ::
[{K, V}].
+-type presence_error(A) ::
+ {keys_missing , [A]}
+ | {keys_duplicated , [A]}
+ | {keys_unsupported , [A]}
+ .
+
%% ============================================================================
%% API
empty() ->
[].
+-spec get(t(K, V), K) ->
+ hope_option:t(V).
get(T, K) ->
case lists:keyfind(K, 1, T)
of false -> none
; {K, V} -> {some, V}
end.
+-spec set(t(K, V), K, V) ->
+ t(K, V).
set(T, K, V) ->
lists:keystore(K, 1, T, {K, V}).
+-spec update(t(K, V), K, fun((hope_option:t(V)) -> V)) ->
+ t(K, V).
update(T, K, F) ->
V1Opt = get(T, K),
V2 = F(V1Opt),
% TODO: Eliminate the 2nd lookup.
set(T, K, V2).
+-spec pop(t(K, V), K) ->
+ {hope_option:t(V), t(K, V)}.
pop(T1, K) ->
case lists:keytake(K, 1, T1)
of {value, {K, V}, T2} -> {{some, V}, T2}
; false -> {none , T1}
end.
+-spec iter(t(K, V), fun((K, V) -> ok)) ->
+ ok.
iter(T, F1) ->
F2 = lift_map(F1),
lists:foreach(F2, T).
+-spec map(t(K, V), fun((K, V) -> V)) ->
+ t(K, V).
map(T, F1) ->
F2 = fun ({K, _}=X) -> {K, apply_map(F1, X)} end,
lists:map(F2, T).
+-spec filter(t(K, V), fun((K, V) -> boolean())) ->
+ t(K, V).
filter(T, F1) ->
F2 = lift_map(F1),
lists:filter(F2, T).
+-spec fold(t(K, V), fun((K, V, Acc) -> Acc), Acc) ->
+ Acc.
fold(T, F1, Accumulator) ->
F2 = fun ({K, V}, Acc) -> F1(K, V, Acc) end,
lists:foldl(F2, Accumulator, T).
+-spec to_kv_list(t(K, V)) ->
+ [{K, V}].
to_kv_list(T) ->
T.
+-spec of_kv_list([{K, V}]) ->
+ t(K, V).
of_kv_list(List) ->
% TODO: Decide if validation is to be done here. Do so if yes.
List.
+-spec validate_unique_presence(t(K, _V), [K]) ->
+ hope_result:t(ok, [presence_error(K)]).
+validate_unique_presence(T, KeysRequired) ->
+ KeysOptional = [],
+ validate_unique_presence(T, KeysRequired, KeysOptional).
+
+-spec validate_unique_presence(t(K, _V), [K], [K]) ->
+ hope_result:t(ok, [presence_error(K)]).
+validate_unique_presence(T, KeysRequired, KeysOptional) ->
+ KeysSupported = KeysRequired ++ KeysOptional,
+ KeysGiven = [K || {K, _V} <- T],
+ KeysGivenUnique = lists:usort(KeysGiven),
+ KeysDups = lists:usort(KeysGiven -- KeysGivenUnique),
+ KeysMissing = KeysRequired -- KeysGivenUnique,
+ KeysUnsupported = KeysGivenUnique -- KeysSupported,
+ case {KeysDups, KeysMissing, KeysUnsupported}
+ of {[], [], []} ->
+ {ok, ok}
+ ; {Dups, Missing, Unsupported} ->
+ ErrorDups =
+ case Dups
+ of [] -> []
+ ; [_|_] -> [{keys_duplicated, Dups}]
+ end,
+ ErrorMissing =
+ case Missing
+ of [] -> []
+ ; [_|_] -> [{keys_missing, Missing}]
+ end,
+ ErrorUnsupported =
+ case Unsupported
+ of [] -> []
+ ; [_|_] -> [{keys_unsupported, Unsupported}]
+ end,
+ Errors = ErrorDups ++ ErrorMissing ++ ErrorUnsupported,
+ {error, Errors}
+ end.
+
%% ============================================================================
%% Helpers