, get/2
, set/3
, update/3
+ , pop/2
, iter/2
, map/2
, filter/2
update(T, K, F) ->
V1Opt = get(T, K),
V2 = F(V1Opt),
+ % TODO: Eliminate the 2nd lookup.
set(T, K, V2).
-iter(T, Map1) ->
- Map2 = lift_map_into_list(Map1),
- lists:foreach(Map2, T).
+pop(T1, K) ->
+ case lists:keytake(K, 1, T1)
+ of {value, {K, V}, T2} -> {{some, V}, T2}
+ ; false -> {none , T1}
+ end.
+
+iter(T, F1) ->
+ F2 = lift_map(F1),
+ lists:foreach(F2, T).
-map(T, Map1) ->
- Map2 = lift_map_into_list(Map1),
- lists:map(Map2, T).
+map(T, F1) ->
+ F2 = fun ({K, _}=X) -> {K, apply_map(F1, X)} end,
+ lists:map(F2, T).
-filter(T, Map1) ->
- Map2 = lift_map_into_list(Map1),
- lists:filter(Map2, T).
+filter(T, F1) ->
+ F2 = lift_map(F1),
+ lists:filter(F2, T).
fold(T, F1, Accumulator) ->
F2 = fun ({K, V}, Acc) -> F1(K, V, Acc) end,
T.
of_kv_list(List) ->
+ % TODO: Decide if validation is to be done here. Do so if yes.
List.
%% Helpers
%% ============================================================================
-lift_map_into_list(Map) ->
- fun ({K, V}) -> {K, Map(K, V)} end.
+-spec lift_map(F) ->
+ G
+ when F :: fun(( K, V1 ) -> V2)
+ , G :: fun(({K, V1}) -> V2)
+ .
+lift_map(F) ->
+ fun (X) -> apply_map(F, X) end.
+
+-spec apply_map(fun((K, V1) -> V2), {K, V1}) ->
+ V2.
+apply_map(F, {K, V}) ->
+ F(K, V).