, get/2
, set/3
, update/3
+ , pop/2
, iter/2
, map/2
, filter/2
% TODO: Eliminate the 2nd lookup.
set(T, K, V2).
+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).