update docs, statebox_orddict:orddict_from_proplist/1

Author: etrepum

CHANGES.md

@@ -1,3 +1,10 @@
+Version 0.2.2 released 2011-06-14
+
+* Updated README
+* statebox_orddict:orddict_from_proplist/1 now uses
+  orddict:from_list/1 instead of lists:usort/1 for correctness
+* Fixed docstring for statebox_orddict:f_subtract/2
+
 Version 0.2.1 released 2011-04-30
 
 * Added LICENSE file (MIT)

README.md

@@ -95,3 +95,30 @@ Using the `statebox_orddict` convenience wrapper:
                              New),
     Resovled = statebox_orddict:from_values([ChildA, ChildB]),
     statebox:value(Resolved) =:= [{a, 1}, {b, 1}, {c, [a, aa, b, bb]}].
+
+Resources
+---------
+
+On Mochi Labs
+=============
+
+[statebox, an eventually consistent data model for Erlang (and Riak)][labs0]
+on the Mochi Labs blog describes the rationale for statebox and shows how it
+works.
+
+[labs0]: http://labs.mochimedia.com/archive/2011/05/08/statebox/
+
+Convergent / Commutative Replicated Data Types
+==============================================
+
+The technique used to implement this is similar to what is described in
+this paper:
+[A comprehensive study of Convergent and Commutative Replicated Data Types][CRDT].
+statebox was developed without knowledge of the paper, so the terminology and
+implementation details differ.
+
+I think the technique used by statebox would be best described as a
+state-based object, although the merge algorithm and event queue
+is similar to how op-based objects are described.
+
+[CRDT]: http://hal.archives-ouvertes.fr/inria-00555588/

src/statebox.app.src

@@ -1,7 +1,7 @@
 {application, statebox,
  [
   {description, "Erlang state \"monad\" with merge/conflict-resolution capabilities. Useful for Riak."},
-  {vsn, "0.2.1"},
+  {vsn, "0.2.2"},
   {registered, []},
   {applications, [
                   kernel,

src/statebox_orddict.erl

@@ -22,11 +22,11 @@ from_values([]) ->
 from_values(Vals) ->
     statebox:merge([as_statebox(V) || V <- Vals]).
 
-%% @doc Convert a proplist() to an orddict() (by sorting it).
+%% @doc Convert a proplist() to an orddict().
 %%      Only [{term(), term()}] proplists are supported.
 -spec orddict_from_proplist(proplist()) -> orddict().
 orddict_from_proplist(P) ->
-    lists:usort(P).
+    orddict:from_list(P).
 
 %% @doc Return true if the statebox's value is [], false otherwise.
 -spec is_empty(statebox()) -> boolean().
@@ -121,6 +121,12 @@ orddict_from_proplist_test() ->
     ?assertEqual(
        [{a, b}, {c, d}],
        orddict_from_proplist([{c, d}, {a, b}])),
+    ?assertEqual(
+       [{a, c}],
+       orddict_from_proplist([{a, b}, {a, c}])),
+    ?assertEqual(
+       [{a, b}],
+       orddict_from_proplist([{a, c}, {a, b}])),
     ok.
 
 is_empty_test() ->