Group menu items into per-category submenus

Parse the Categories key from .desktop files and have the renderer
emit one <menu> submenu per category (via xmerl), with items sorted
within each; entries in multiple categories appear in each submenu,
and uncategorized entries fall into a catch-all "Other" submenu.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

6 files changed, 206 insertions, 78 deletions

diff --git a/include/er_xdg_pipe_menu.hrl b/include/er_xdg_pipe_menu.hrl
index 2cee607..6d50b8d 100644
--- a/include/er_xdg_pipe_menu.hrl
+++ b/include/er_xdg_pipe_menu.hrl
@@ -2,5 +2,6 @@
     name :: binary(),
     exec :: binary(),
     icon :: binary() | undefined,
+    categories :: [binary()],
     hidden :: boolean()
 }).
diff --git a/src/er_xdg_pipe_menu.app.src b/src/er_xdg_pipe_menu.app.src
index 7013bc7..1649ec3 100644
--- a/src/er_xdg_pipe_menu.app.src
+++ b/src/er_xdg_pipe_menu.app.src
@@ -5,7 +5,8 @@
     {mod, {er_xdg_pipe_menu_app, []}},
     {applications, [
         kernel,
-        stdlib
+        stdlib,
+        xmerl
     ]},
     {env, []},
     {modules, []},
diff --git a/src/er_xdg_pipe_menu_desktop_entry.erl b/src/er_xdg_pipe_menu_desktop_entry.erl
index bbd2594..9a71013 100644
--- a/src/er_xdg_pipe_menu_desktop_entry.erl
+++ b/src/er_xdg_pipe_menu_desktop_entry.erl
@@ -3,8 +3,9 @@
 %%
 %% Reads the `[Desktop Entry]' group of a desktop entry file and
 %% extracts the fields needed to build a menu item: `Name', `Exec'
-%% and (optionally) `Icon'. Other groups (e.g. `[Desktop Action ...]')
-%% and localized keys (e.g. `Name[fr]') are ignored.
+%% and (optionally) `Icon' and `Categories'. Other groups (e.g.
+%% `[Desktop Action ...]') and localized keys (e.g. `Name[fr]') are
+%% ignored.
 %% @end
 %%%-------------------------------------------------------------------
 
@@ -16,7 +17,7 @@
 
 -define(GROUP, <<"Desktop Entry">>).
 -define(WANTED_KEYS, [
-    <<"Name">>, <<"Exec">>, <<"Icon">>, <<"NoDisplay">>, <<"Hidden">>, <<"Type">>
+    <<"Name">>, <<"Exec">>, <<"Icon">>, <<"Categories">>, <<"NoDisplay">>, <<"Hidden">>, <<"Type">>
 ]).
 -define(FIELD_CODES, "fFuUdDnNickvm").
 
@@ -99,11 +100,20 @@ to_entry(Fields) ->
                         name = Name,
                         exec = strip_field_codes(Exec),
                         icon = maps:get(<<"Icon">>, Fields, undefined),
+                        categories = parse_categories(maps:get(<<"Categories">>, Fields, undefined)),
                         hidden = is_hidden(Fields)
                     }}
             end
     end.
 
+%% `Categories' is a `;'-separated list, conventionally with a
+%% trailing separator (e.g. `Utility;Development;'); empty segments
+%% from that trailing separator (or repeated ones) are dropped.
+parse_categories(undefined) ->
+    [];
+parse_categories(Bin) ->
+    [C || C <- binary:split(Bin, <<";">>, [global]), C =/= <<>>].
+
 %% Niche variations (e.g. a Type-less override dropped into
 %% ~/.local/share/applications) are left to be special-cased there
 %% rather than accounted for here.
diff --git a/src/er_xdg_pipe_menu_renderer.erl b/src/er_xdg_pipe_menu_renderer.erl
index fafed45..f89d868 100644
--- a/src/er_xdg_pipe_menu_renderer.erl
+++ b/src/er_xdg_pipe_menu_renderer.erl
@@ -2,9 +2,13 @@
 %% @doc Renders parsed desktop entries as an Openbox pipe menu.
 %%
 %% Given a list of `#desktop_entry{}' records, produces the XML that
-%% Openbox expects on stdout from a pipe menu: one `<item>' per
-%% visible entry (entries with `hidden = true' are dropped), sorted
-%% case-insensitively by name, each wrapping an `Execute' action.
+%% Openbox expects on stdout from a pipe menu: one `<menu>' submenu
+%% per category, each containing an `<item>' per visible entry in
+%% that category (entries with `hidden = true' are dropped). An entry
+%% belonging to several categories appears in each of their submenus;
+%% an entry with no categories is placed in a catch-all `Other'
+%% submenu. Categories are sorted case-insensitively, and entries
+%% within a submenu are sorted case-insensitively by name.
 %% @end
 %%%-------------------------------------------------------------------
 
@@ -14,45 +18,61 @@
 
 -export([render/1]).
 
+-define(OTHER_CATEGORY, <<"Other">>).
+
 -spec render([#desktop_entry{}]) -> binary().
 render(Entries) ->
     Visible = [E || E <- Entries, not E#desktop_entry.hidden],
-    Sorted = lists:sort(fun by_name/2, Visible),
-    iolist_to_binary([
-        <<"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n">>,
-        <<"<openbox_pipe_menu>\n">>,
-        [render_item(E) || E <- Sorted],
-        <<"</openbox_pipe_menu>\n">>
-    ]).
+    Grouped = group_by_category(Visible),
+    Categories = lists:sort(fun category_lt/2, maps:keys(Grouped)),
+    Menu = {openbox_pipe_menu, [], submenus_content(Categories, Grouped)},
+    Xml = xmerl:export_simple(
+        [Menu],
+        xmerl_xml,
+        [{prolog, ["<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"]}]
+    ),
+    iolist_to_binary([Xml, "\n"]).
+
+group_by_category(Entries) ->
+    lists:foldl(fun add_entry_to_categories/2, #{}, Entries).
+
+add_entry_to_categories(#desktop_entry{categories = []} = E, Acc) ->
+    add_entry_to_category(?OTHER_CATEGORY, E, Acc);
+add_entry_to_categories(#desktop_entry{categories = Cats} = E, Acc) ->
+    lists:foldl(fun(Cat, Acc0) -> add_entry_to_category(Cat, E, Acc0) end, Acc, Cats).
+
+add_entry_to_category(Cat, E, Acc) ->
+    maps:update_with(Cat, fun(Es) -> [E | Es] end, [E], Acc).
+
+category_lt(A, B) -> string:lowercase(A) =< string:lowercase(B).
 
 by_name(#desktop_entry{name = A}, #desktop_entry{name = B}) ->
     string:lowercase(A) =< string:lowercase(B).
 
-render_item(#desktop_entry{name = Name, exec = Exec, icon = Icon}) ->
-    [
-        <<"  <item label=\"">>,
-        escape_attr(Name),
-        <<"\"">>,
-        icon_attr(Icon),
-        <<">\n">>,
-        <<"    <action name=\"Execute\">\n">>,
-        <<"      <command>">>,
-        escape_text(Exec),
-        <<"</command>\n">>,
-        <<"    </action>\n">>,
-        <<"  </item>\n">>
-    ].
-
-icon_attr(undefined) -> <<>>;
-icon_attr(Icon) -> [<<" icon=\"">>, escape_attr(Icon), <<"\"">>].
-
-%% Attribute values additionally need '"' escaped; text content doesn't.
-escape_attr(Bin) -> escape(Bin, [{<<"\"">>, <<"&quot;">>}]).
-escape_text(Bin) -> escape(Bin, []).
-
-escape(Bin, Extra) ->
-    lists:foldl(
-        fun({Pat, Repl}, Acc) -> binary:replace(Acc, Pat, Repl, [global]) end,
-        Bin,
-        [{<<"&">>, <<"&amp;">>}, {<<"<">>, <<"&lt;">>}, {<<">">>, <<"&gt;">>} | Extra]
+submenus_content(Categories, Grouped) ->
+    lists:foldr(
+        fun(Cat, Acc) -> ["\n  ", submenu_element(Cat, Grouped) | Acc] end, ["\n"], Categories
     ).
+
+submenu_element(Cat, Grouped) ->
+    Entries = lists:sort(fun by_name/2, maps:get(Cat, Grouped)),
+    {menu, [{id, Cat}, {label, Cat}], items_content(Entries)}.
+
+items_content(Entries) ->
+    lists:foldr(fun(E, Acc) -> ["\n    ", item_element(E) | Acc] end, ["\n  "], Entries).
+
+item_element(#desktop_entry{name = Name, exec = Exec, icon = Icon}) ->
+    {item, item_attrs(Name, Icon), [
+        "\n      ",
+        {action, [{name, <<"Execute">>}], [
+            "\n        ",
+            {command, [], [text(Exec)]},
+            "\n      "
+        ]},
+        "\n    "
+    ]}.
+
+item_attrs(Name, undefined) -> [{label, Name}];
+item_attrs(Name, Icon) -> [{label, Name}, {icon, Icon}].
+
+text(Bin) -> unicode:characters_to_list(Bin).
diff --git a/test/er_xdg_pipe_menu_desktop_entry_tests.erl b/test/er_xdg_pipe_menu_desktop_entry_tests.erl
index 399e3a5..bcea976 100644
--- a/test/er_xdg_pipe_menu_desktop_entry_tests.erl
+++ b/test/er_xdg_pipe_menu_desktop_entry_tests.erl
@@ -13,7 +13,7 @@ basic_entry_test() ->
     >>,
     ?assertEqual(
         {ok, #desktop_entry{
-            name = <<"Firefox">>, exec = <<"firefox">>, icon = <<"firefox">>, hidden = false
+            name = <<"Firefox">>, exec = <<"firefox">>, icon = <<"firefox">>, categories = [], hidden = false
         }},
         er_xdg_pipe_menu_desktop_entry:parse(Bin)
     ).
@@ -25,10 +25,35 @@ icon_is_optional_test() ->
         "Exec=foo\n"
     >>,
     ?assertEqual(
-        {ok, #desktop_entry{name = <<"Foo">>, exec = <<"foo">>, icon = undefined, hidden = false}},
+        {ok, #desktop_entry{name = <<"Foo">>, exec = <<"foo">>, icon = undefined, categories = [], hidden = false}},
         er_xdg_pipe_menu_desktop_entry:parse(Bin)
     ).
 
+categories_are_split_on_semicolon_test() ->
+    Bin = <<
+        "[Desktop Entry]\n"
+        "Name=Foo\n"
+        "Exec=foo\n"
+        "Categories=Utility;Development;\n"
+    >>,
+    {ok, Entry} = er_xdg_pipe_menu_desktop_entry:parse(Bin),
+    ?assertEqual([<<"Utility">>, <<"Development">>], Entry#desktop_entry.categories).
+
+categories_is_empty_list_when_absent_test() ->
+    Bin = <<"[Desktop Entry]\nName=Foo\nExec=foo\n">>,
+    {ok, Entry} = er_xdg_pipe_menu_desktop_entry:parse(Bin),
+    ?assertEqual([], Entry#desktop_entry.categories).
+
+repeated_category_separators_are_ignored_test() ->
+    Bin = <<
+        "[Desktop Entry]\n"
+        "Name=Foo\n"
+        "Exec=foo\n"
+        "Categories=Utility;;Development\n"
+    >>,
+    {ok, Entry} = er_xdg_pipe_menu_desktop_entry:parse(Bin),
+    ?assertEqual([<<"Utility">>, <<"Development">>], Entry#desktop_entry.categories).
+
 missing_name_test() ->
     Bin = <<"[Desktop Entry]\nExec=foo\n">>,
     ?assertEqual({error, missing_name}, er_xdg_pipe_menu_desktop_entry:parse(Bin)).
@@ -48,7 +73,7 @@ ignores_other_groups_test() ->
         "Exec=foo --new-window\n"
     >>,
     ?assertEqual(
-        {ok, #desktop_entry{name = <<"Foo">>, exec = <<"foo">>, icon = undefined, hidden = false}},
+        {ok, #desktop_entry{name = <<"Foo">>, exec = <<"foo">>, icon = undefined, categories = [], hidden = false}},
         er_xdg_pipe_menu_desktop_entry:parse(Bin)
     ).
 
@@ -63,7 +88,7 @@ ignores_comments_and_blank_lines_test() ->
         "Exec=foo\n"
     >>,
     ?assertEqual(
-        {ok, #desktop_entry{name = <<"Foo">>, exec = <<"foo">>, icon = undefined, hidden = false}},
+        {ok, #desktop_entry{name = <<"Foo">>, exec = <<"foo">>, icon = undefined, categories = [], hidden = false}},
         er_xdg_pipe_menu_desktop_entry:parse(Bin)
     ).
 
@@ -74,7 +99,7 @@ strips_multiple_field_codes_test() ->
         "Exec=foo %f --flag %i %c\n"
     >>,
     ?assertEqual(
-        {ok, #desktop_entry{name = <<"Foo">>, exec = <<"foo --flag">>, icon = undefined, hidden = false}},
+        {ok, #desktop_entry{name = <<"Foo">>, exec = <<"foo --flag">>, icon = undefined, categories = [], hidden = false}},
         er_xdg_pipe_menu_desktop_entry:parse(Bin)
     ).
 
@@ -86,7 +111,7 @@ literal_percent_is_unescaped_test() ->
     >>,
     ?assertEqual(
         {ok, #desktop_entry{
-            name = <<"Foo">>, exec = <<"foo --progress=%">>, icon = undefined, hidden = false
+            name = <<"Foo">>, exec = <<"foo --progress=%">>, icon = undefined, categories = [], hidden = false
         }},
         er_xdg_pipe_menu_desktop_entry:parse(Bin)
     ).
@@ -94,7 +119,7 @@ literal_percent_is_unescaped_test() ->
 unescapes_value_test() ->
     Bin = <<"[Desktop Entry]\nName=Foo\\sBar\nExec=foo\n">>,
     ?assertEqual(
-        {ok, #desktop_entry{name = <<"Foo Bar">>, exec = <<"foo">>, icon = undefined, hidden = false}},
+        {ok, #desktop_entry{name = <<"Foo Bar">>, exec = <<"foo">>, icon = undefined, categories = [], hidden = false}},
         er_xdg_pipe_menu_desktop_entry:parse(Bin)
     ).
 
@@ -141,7 +166,7 @@ parse_file_test() ->
     Result = er_xdg_pipe_menu_desktop_entry:parse_file(Path),
     ok = file:delete(Path),
     ?assertEqual(
-        {ok, #desktop_entry{name = <<"Foo">>, exec = <<"foo">>, icon = undefined, hidden = false}},
+        {ok, #desktop_entry{name = <<"Foo">>, exec = <<"foo">>, icon = undefined, categories = [], hidden = false}},
         Result
     ).
 
diff --git a/test/er_xdg_pipe_menu_renderer_tests.erl b/test/er_xdg_pipe_menu_renderer_tests.erl
index 1fc0192..7273625 100644
--- a/test/er_xdg_pipe_menu_renderer_tests.erl
+++ b/test/er_xdg_pipe_menu_renderer_tests.erl
@@ -5,10 +5,15 @@
 -include("er_xdg_pipe_menu.hrl").
 
 entry(Name, Exec, Icon) ->
-    entry(Name, Exec, Icon, false).
+    entry(Name, Exec, Icon, []).
 
-entry(Name, Exec, Icon, Hidden) ->
-    #desktop_entry{name = Name, exec = Exec, icon = Icon, hidden = Hidden}.
+entry(Name, Exec, Icon, Categories) ->
+    entry(Name, Exec, Icon, Categories, false).
+
+entry(Name, Exec, Icon, Categories, Hidden) ->
+    #desktop_entry{
+        name = Name, exec = Exec, icon = Icon, categories = Categories, hidden = Hidden
+    }.
 
 empty_list_renders_empty_menu_test() ->
     ?assertEqual(
@@ -19,47 +24,76 @@ empty_list_renders_empty_menu_test() ->
     ).
 
 single_entry_with_icon_test() ->
-    Rendered = er_xdg_pipe_menu_renderer:render([entry(<<"Firefox">>, <<"firefox">>, <<"firefox">>)]),
+    Rendered = er_xdg_pipe_menu_renderer:render([
+        entry(<<"Firefox">>, <<"firefox">>, <<"firefox">>, [<<"Network">>])
+    ]),
     ?assertEqual(
         <<"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
           "<openbox_pipe_menu>\n"
-          "  <item label=\"Firefox\" icon=\"firefox\">\n"
-          "    <action name=\"Execute\">\n"
-          "      <command>firefox</command>\n"
-          "    </action>\n"
-          "  </item>\n"
+          "  <menu id=\"Network\" label=\"Network\">\n"
+          "    <item label=\"Firefox\" icon=\"firefox\">\n"
+          "      <action name=\"Execute\">\n"
+          "        <command>firefox</command>\n"
+          "      </action>\n"
+          "    </item>\n"
+          "  </menu>\n"
           "</openbox_pipe_menu>\n">>,
         Rendered
     ).
 
 entry_without_icon_omits_icon_attr_test() ->
+    Rendered = er_xdg_pipe_menu_renderer:render([
+        entry(<<"Foo">>, <<"foo">>, undefined, [<<"Utility">>])
+    ]),
+    ?assertEqual(
+        <<"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+          "<openbox_pipe_menu>\n"
+          "  <menu id=\"Utility\" label=\"Utility\">\n"
+          "    <item label=\"Foo\">\n"
+          "      <action name=\"Execute\">\n"
+          "        <command>foo</command>\n"
+          "      </action>\n"
+          "    </item>\n"
+          "  </menu>\n"
+          "</openbox_pipe_menu>\n">>,
+        Rendered
+    ).
+
+entries_without_categories_go_in_other_submenu_test() ->
     Rendered = er_xdg_pipe_menu_renderer:render([entry(<<"Foo">>, <<"foo">>, undefined)]),
     ?assertEqual(
         <<"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
           "<openbox_pipe_menu>\n"
-          "  <item label=\"Foo\">\n"
-          "    <action name=\"Execute\">\n"
-          "      <command>foo</command>\n"
-          "    </action>\n"
-          "  </item>\n"
+          "  <menu id=\"Other\" label=\"Other\">\n"
+          "    <item label=\"Foo\">\n"
+          "      <action name=\"Execute\">\n"
+          "        <command>foo</command>\n"
+          "      </action>\n"
+          "    </item>\n"
+          "  </menu>\n"
           "</openbox_pipe_menu>\n">>,
         Rendered
     ).
 
 hidden_entries_are_dropped_test() ->
     Entries = [
-        entry(<<"Visible">>, <<"visible">>, undefined),
-        entry(<<"Invisible">>, <<"invisible">>, undefined, true)
+        entry(<<"Visible">>, <<"visible">>, undefined, [<<"Utility">>]),
+        entry(<<"Invisible">>, <<"invisible">>, undefined, [<<"Utility">>], true)
     ],
     Rendered = er_xdg_pipe_menu_renderer:render(Entries),
     ?assertNot(binary:match(Rendered, <<"Invisible">>) =/= nomatch),
     ?assert(binary:match(Rendered, <<"Visible">>) =/= nomatch).
 
-entries_are_sorted_case_insensitively_test() ->
+hidden_entry_leaves_no_empty_submenu_test() ->
+    Entries = [entry(<<"Invisible">>, <<"invisible">>, undefined, [<<"Utility">>], true)],
+    Rendered = er_xdg_pipe_menu_renderer:render(Entries),
+    ?assertNot(binary:match(Rendered, <<"Utility">>) =/= nomatch).
+
+entries_are_sorted_case_insensitively_within_a_submenu_test() ->
     Entries = [
-        entry(<<"zeta">>, <<"zeta">>, undefined),
-        entry(<<"Alpha">>, <<"alpha">>, undefined),
-        entry(<<"beta">>, <<"beta">>, undefined)
+        entry(<<"zeta">>, <<"zeta">>, undefined, [<<"Utility">>]),
+        entry(<<"Alpha">>, <<"alpha">>, undefined, [<<"Utility">>]),
+        entry(<<"beta">>, <<"beta">>, undefined, [<<"Utility">>])
     ],
     Rendered = er_xdg_pipe_menu_renderer:render(Entries),
     Positions = [
@@ -69,28 +103,65 @@ entries_are_sorted_case_insensitively_test() ->
     ],
     ?assertEqual(Positions, lists:sort(Positions)).
 
+submenus_are_sorted_case_insensitively_test() ->
+    Entries = [
+        entry(<<"Zed App">>, <<"zed">>, undefined, [<<"zeta">>]),
+        entry(<<"Alpha App">>, <<"alpha">>, undefined, [<<"Alpha">>]),
+        entry(<<"Beta App">>, <<"beta">>, undefined, [<<"beta">>])
+    ],
+    Rendered = er_xdg_pipe_menu_renderer:render(Entries),
+    Positions = [
+        element(1, binary:match(Rendered, <<"label=\"Alpha\"">>)),
+        element(1, binary:match(Rendered, <<"label=\"beta\"">>)),
+        element(1, binary:match(Rendered, <<"label=\"zeta\"">>))
+    ],
+    ?assertEqual(Positions, lists:sort(Positions)).
+
+entry_with_multiple_categories_appears_in_each_submenu_test() ->
+    Entries = [entry(<<"Foo">>, <<"foo">>, undefined, [<<"Utility">>, <<"Development">>])],
+    Rendered = er_xdg_pipe_menu_renderer:render(Entries),
+    {Doc, _Rest} = xmerl_scan:string(binary_to_list(Rendered)),
+    Menus = [E || E = #xmlElement{name = menu} <- Doc#xmlElement.content],
+    ?assertEqual([<<"Development">>, <<"Utility">>], lists:sort([menu_id(M) || M <- Menus])),
+    Items = [I || M <- Menus, I = #xmlElement{name = item} <- M#xmlElement.content],
+    ?assertEqual(2, length(Items)).
+
 escapes_special_characters_test() ->
-    Entry = entry(<<"Foo & <Bar> \"Baz\"">>, <<"foo --title=\"<x>&y\"">>, <<"icon\"&<>">>),
+    Entry = entry(
+        <<"Foo & <Bar> \"Baz\"">>,
+        <<"foo --title=\"<x>&y\"">>,
+        <<"icon\"&<>">>,
+        [<<"Foo & <Bar>">>]
+    ),
     Rendered = er_xdg_pipe_menu_renderer:render([Entry]),
     ?assertEqual(
         <<"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
           "<openbox_pipe_menu>\n"
-          "  <item label=\"Foo &amp; &lt;Bar&gt; &quot;Baz&quot;\" icon=\"icon&quot;&amp;&lt;&gt;\">\n"
-          "    <action name=\"Execute\">\n"
-          "      <command>foo --title=\"&lt;x&gt;&amp;y\"</command>\n"
-          "    </action>\n"
-          "  </item>\n"
+          "  <menu id=\"Foo &amp; &lt;Bar>\" label=\"Foo &amp; &lt;Bar>\">\n"
+          "    <item label=\"Foo &amp; &lt;Bar> &quot;Baz&quot;\" icon=\"icon&quot;&amp;&lt;>\">\n"
+          "      <action name=\"Execute\">\n"
+          "        <command>foo --title=\"&lt;x&gt;&amp;y\"</command>\n"
+          "      </action>\n"
+          "    </item>\n"
+          "  </menu>\n"
           "</openbox_pipe_menu>\n">>,
         Rendered
     ).
 
 output_is_well_formed_xml_test() ->
     Entries = [
-        entry(<<"Firefox">>, <<"firefox">>, <<"firefox">>),
-        entry(<<"Foo & Bar">>, <<"foo">>, undefined)
+        entry(<<"Firefox">>, <<"firefox">>, <<"firefox">>, [<<"Network">>]),
+        entry(<<"Foo & Bar">>, <<"foo">>, undefined, [<<"Network">>])
     ],
     Rendered = er_xdg_pipe_menu_renderer:render(Entries),
     {Doc, _Rest} = xmerl_scan:string(binary_to_list(Rendered)),
     ?assertEqual(openbox_pipe_menu, Doc#xmlElement.name),
-    Items = [E || E = #xmlElement{name = item} <- Doc#xmlElement.content],
+    Menus = [E || E = #xmlElement{name = menu} <- Doc#xmlElement.content],
+    ?assertEqual(1, length(Menus)),
+    [Menu] = Menus,
+    Items = [E || E = #xmlElement{name = item} <- Menu#xmlElement.content],
     ?assertEqual(2, length(Items)).
+
+menu_id(#xmlElement{attributes = Attrs}) ->
+    [Value] = [V || #xmlAttribute{name = id, value = V} <- Attrs],
+    list_to_binary(Value).