Add keys/1

Makefile

@@ -1,6 +1,6 @@
 PROJECT = gb_merkle_trees
 PROJECT_DESCRIPTION = General balanced Merkle trees
-PROJECT_VERSION = 0.2.1
+PROJECT_VERSION = 0.2.2
 
 TEST_DEPS = triq
 dep_triq = git https://gitlab.com/triq/triq.git e5ba907a11985bf8150f5b5b332d39516ab15857

ebin/gb_merkle_trees.app

@@ -1,6 +1,6 @@
 {application, 'gb_merkle_trees', [
 	{description, "General balanced Merkle trees"},
-	{vsn, "0.2.0"},
+	{vsn, "0.2.2"},
 	{modules, ['gb_bench','gb_merkle_trees']},
 	{registered, []},
 	{applications, [kernel,stdlib,crypto]},

src/gb_merkle_trees.erl

@@ -36,6 +36,7 @@
          from_list/1,
          from_orddict/1,
          from_orddict/2,
+         keys/1,
          lookup/2,
          merkle_proof/2,
          root_hash/1,
@@ -198,6 +199,14 @@ to_orddict(Tree) ->
       [],
       Tree).
 
+-spec keys(tree()) -> list(key()).
+%% @doc Return the keys as an ordered list.
+keys(Tree) ->
+    foldr(
+      fun ({Key, _}, Acc) -> [Key|Acc] end,
+      [],
+      Tree).
+
 -spec foldr(fun(({key(), value()}, Acc :: any()) -> any()), Acc :: any(), tree()) -> Acc :: any().
 %% @doc Iterate through keys and values, from those with highest keys to lowest.
 foldr(Fun, Acc, {_, RootNode}) ->
@@ -510,6 +519,8 @@ prop_orddict_conversion_idempotence() ->
     ?FORALL(KVO, kv_orddict(), KVO =:= to_orddict(from_orddict(KVO))).
 prop_from_orddict_returns_a_perfectly_balanced_tree() ->
     ?FORALL(KVO, kv_orddict(), is_perfectly_balanced(from_orddict(KVO))).
+prop_keys() ->
+    ?FORALL(Tree, tree(), keys(Tree) =:= [Key || {Key, _} <- to_orddict(Tree)]).
 from_list_sometimes_doesnt_return_a_perfectly_balanced_tree_test() ->
     ?assertNotEqual(
        true,