Added exclude_field method to rfc4627.

src/rfc4627.erl

@@ -94,7 +94,7 @@
 -export([unicode_decode/1, unicode_encode/1]).
 -export([from_record/3, to_record/3]).
 -export([hex_digit/1, digit_hex/1]).
--export([get_field/2, get_field/3, set_field/3]).
+-export([get_field/2, get_field/3, set_field/3, exclude_field/2]).
 -export([equiv/2]).
 
 %% @spec () -> string()
@@ -357,7 +357,7 @@ parse_codepoint([$" | Rest]) -> %% " emacs balancing
     {done, Rest};
 parse_codepoint([$\\, Key | Rest]) ->
     parse_general_char(Key, Rest);
-parse_codepoint([X | Rest]) ->					   
+parse_codepoint([X | Rest]) ->
     {ok, X, Rest}.
 
 parse_general_char($b, Rest) -> {ok, 8, Rest};
@@ -526,6 +526,11 @@ decode_record_fields(Values, Fallback, Index, [Field | Rest]) ->
 	     element(Index, Fallback)
      end | decode_record_fields(Values, Fallback, Index + 1, Rest)].
 
+%% @spec (JsonOnbect::jsonobj(), atom()) -> jsononj()
+%% @doc Exclude a named field from a JSON "object".
+exclude_field({obj, Props}, Key) ->
+    {obj, lists:keydelete(Key, 1, Props)}.
+
 %% @spec (JsonObject::jsonobj(), atom()) -> {ok, json()} | not_found
 %% @doc Retrieves the value of a named field of a JSON "object".
 get_field({obj, Props}, Key) ->

test/test_rfc4627.erl

@@ -38,6 +38,7 @@ test_all() ->
     passed = test_unicode(),
     passed = test_equiv(),
     passed = test_eof_detection(),
+    passed = test_exclude(),
     passed.
 
 test_codec() ->
@@ -158,6 +159,21 @@ test_dict() ->
     {ok, [1, 2]} = rfc4627:get_field(Obj, "c"),
     passed.
 
+test_exclude() ->
+    Dict = dict:store("c", 2,
+                        dict:store("b", <<"hello">>,
+                            dict:store("a", 123, dict:new()))),
+    {ok, Obj, ""} = rfc4627:decode(rfc4627:encode(Dict)),
+    Obj2 = rfc4627:exclude_field(Obj, "a"),
+    true = rfc4627:equiv({obj, [{"c", 2}, {"b", <<"hello">>}]}, Obj2),
+    Obj3 = rfc4627:exclude_field(Obj2, "b"),
+    true = rfc4627:equiv({obj, [{"c", 2}]}, Obj3),
+    Obj4 = rfc4627:exclude_field(Obj3, "x"),
+    true = rfc4627:equiv({obj, [{"c", 2}]}, Obj4),
+    Obj5 = rfc4627:exclude_field(Obj3, "c"),
+    true = rfc4627:equiv({obj, []}, Obj5),
+    passed.
+
 test_equiv() ->
     true = rfc4627:equiv([1, 2], [1, 2]),
     false = rfc4627:equiv([1, 2], [2, 1]),