fix sorting_criterion/criteria typo

src/client/spark/Modules/Market/MarketView/MarketViewVM.cs

@@ -162,7 +162,7 @@ namespace mbts.spark {
                      strip_name_filter.load_state(filters.strip_name);
                      mic_code_filter.load_state(filters.mic_code);
                   }
-                  rows_view.set_sort_descriptions(s.sorting_criterion, columns);
+                  rows_view.set_sort_descriptions(s.sorting_criteria, columns);
                }
             }), DataGridFilterHelper.hook_filters(rows_view, _filters),
             settings_manager.subscribe_current().OnDispatcher().Subscribe(grid_settings_manager),

src/client/spark/Modules/Market/MarketView/MarketViewWindowFactory.cs

@@ -91,9 +91,9 @@ namespace bts.shell {
          }
 
 
-         public static GridSettings DefaultGridSettings => GridSettings.Default.with(DefaultColumns.all, DefaultColumns.default_sorting_criterion, enable_background_color: true);
+         public static GridSettings DefaultGridSettings => GridSettings.Default.with(DefaultColumns.all, DefaultColumns.default_sorting_criteria, enable_background_color: true);
 
-         public IReadOnlyList<SortingCriteria> sorting_criterion => _sorting_criteria ?? (_sorting_criteria = DefaultColumns.default_sorting_criterion.ToList());
+         public IReadOnlyList<SortingCriteria> sorting_criteria => _sorting_criteria ?? (_sorting_criteria = DefaultColumns.default_sorting_criteria.ToList());
 
          public static StartupData Default(SecurityCriteria security_criteria) =>
             new StartupData(security_criteria, new FilterStates(), null);
@@ -131,7 +131,7 @@ namespace bts.shell {
 
 
 
-            public static IEnumerable<SortingCriteria> default_sorting_criterion {
+            public static IEnumerable<SortingCriteria> default_sorting_criteria {
                get {
                   yield return new SortingCriteria(security.id, true);
                }

src/client/spark/Modules/Market/TimeAndSales/Settings/TimeAndSalesSettings.cs

@@ -13,7 +13,7 @@ namespace bts.shell.time_and_sales {
       [ProtoMember(1)]
       public readonly SecurityCriteria security_criteria;
       [ProtoMember(2)]
-      List<SortingCriteria> _sorting_criterion;
+      List<SortingCriteria> _sorting_criteria;
       [ProtoMember(3)]
       public FilterStates filters;
       [ProtoMember(4)]
@@ -28,19 +28,19 @@ namespace bts.shell.time_and_sales {
       public TimeAndSalesSettings(SecurityCriteria security_criteria) :
          this(security_criteria, new FilterStates(), null, null) { }
 
-      public TimeAndSalesSettings(SecurityCriteria security_criteria, FilterStates filters, GridSettings grid = default, List<SortingCriteria> sorting_criterion = null) {
+      public TimeAndSalesSettings(SecurityCriteria security_criteria, FilterStates filters, GridSettings grid = default, List<SortingCriteria> sorting_criteria = null) {
          this.security_criteria = security_criteria;
          this.filters = filters;
          this.grid = grid;
-         _sorting_criterion = sorting_criterion;
+         _sorting_criteria = sorting_criteria;
       }
 
-      public static GridSettings DefaultGridSettings => GridSettings.Default.with(DefaultColumns.all, DefaultColumns.default_sorting_criterion);
+      public static GridSettings DefaultGridSettings => GridSettings.Default.with(DefaultColumns.all, DefaultColumns.default_sorting_criteria);
 
-      public List<SortingCriteria> sorting_criterion => _sorting_criterion ?? (_sorting_criterion = DefaultColumns.default_sorting_criterion.ToList());
+      public List<SortingCriteria> sorting_criteria => _sorting_criteria ?? (_sorting_criteria = DefaultColumns.default_sorting_criteria.ToList());
 
       public static TimeAndSalesSettings Default(SecurityCriteria security_criteria) =>
-        new TimeAndSalesSettings(security_criteria, new FilterStates(), null, DefaultColumns.default_sorting_criterion.ToList());
+        new TimeAndSalesSettings(security_criteria, new FilterStates(), null, DefaultColumns.default_sorting_criteria.ToList());
 
       public TimeAndSalesSettings with(SecurityCriteria security_criteria) =>
          new TimeAndSalesSettings(security_criteria, filters, grid);
@@ -53,7 +53,7 @@ namespace bts.shell.time_and_sales {
          public static GridColumnSettings aggressor => new GridColumnSettings(Columns.Aggressor.col_id(), DefaultColumnHeaders.Aggressor, width: DefaultColumnWidths.Aggressor);
          public static GridColumnSettings security_key => new GridColumnSettings(Columns.SecurityKey.col_id(), DefaultColumnHeaders.SecurityKey, is_visible: false, width: DefaultColumnWidths.SecurityKey);
 
-         public static IEnumerable<SortingCriteria> default_sorting_criterion {
+         public static IEnumerable<SortingCriteria> default_sorting_criteria {
             get {
                yield return new SortingCriteria(time.id, false);
             }

src/client/spark/Modules/Market/TimeAndSales/TimeAndSalesWindow.cs

@@ -159,7 +159,7 @@ namespace bts.shell.time_and_sales {
             })),
             _menu_display_vm.spark_cmd
          };
-         _vm.load(_state.filters, _state.sorting_criterion, _state.grid);
+         _vm.load(_state.filters, _state.sorting_criteria, _state.grid);
          _vm.request_show_ladder += show_ladder;
          var security_criteria_src = _bus.subscribe(update_securities_cmd.tag);
          var subs = new List<IDisposable> {

src/client/spark/Modules/Spreader/SyntheticManagementWindowFactory.cs

@@ -70,7 +70,7 @@ namespace bts.shell {
                grid ?? this.grid,
                menu_display ?? this.menu_display);
 
-         public static GridSettings DefaultGridSettings => GridSettings.Default.with(DefaultColumns.all, DefaultColumns.default_sorting_criterion);
+         public static GridSettings DefaultGridSettings => GridSettings.Default.with(DefaultColumns.all, DefaultColumns.default_sorting_criteria);
 
          static class DefaultColumns {
             public static GridColumnSettings name => new GridColumnSettings(col_id(Columns.Name), DefaultColumnHeaders.Name, width: DefaultColumnWidths.Security);
@@ -80,7 +80,7 @@ namespace bts.shell {
             public static GridColumnSettings security_key => new GridColumnSettings(col_id(Columns.SecurityKey), DefaultColumnHeaders.SecurityKey, is_visible: false, width: DefaultColumnWidths.SecurityKey);
             public static GridColumnSettings user => new GridColumnSettings(col_id(Columns.User), DefaultColumnHeaders.User, is_visible: false, width: DefaultColumnWidths.User);
 
-            public static IEnumerable<SortingCriteria> default_sorting_criterion {
+            public static IEnumerable<SortingCriteria> default_sorting_criteria {
                get {
                   yield return new SortingCriteria(name.id, true);
                }

src/client/spark/Modules/Trading/Fills/FillsVM.cs

@@ -154,7 +154,7 @@ namespace mbts.spark {
                TimeTextTuple.FromDateTime(DateTime.Today),
                TimeTextTuple.FromDateTime(DateTime.Today.AddDays(1)))
          },
-         settings.sorting_criterion);
+         settings.sorting_criteria);
          // resources/subscriptions
          _dispose = new CompositeDisposable(
             ObservableAutoWrapper.connect(col_tups, columns, ct => ct.col),
@@ -209,8 +209,8 @@ namespace mbts.spark {
       public FillsFilterStates get_filters() =>
          _rows_manager.get_filters();
 
-      public IEnumerable<SortingCriteria> get_sorting_criterion() =>
-         _rows_manager.get_sorting_criterion();
+      public IEnumerable<SortingCriteria> get_sorting_criteria() =>
+         _rows_manager.get_sorting_criteria();
 
       public void on_sorting(object sender, DIYGridSortingEventArgs e) =>
          _rows_manager.on_sorting(e);

src/client/spark/Modules/Trading/Fills/FillsWindow.cs

@@ -40,7 +40,7 @@ namespace mbts.spark {
       public override UIElement Content => _view;
       public override IEnumerable<SparkCommand> Commands => _commands;
 
-      public override FillsSettings SaveState => _state = new FillsSettings(_state.orders, _vm.get_sorting_criterion().ToList(), _vm.get_filters(), _vm.get_grid_save_state()) {
+      public override FillsSettings SaveState => _state = new FillsSettings(_state.orders, _vm.get_sorting_criteria().ToList(), _vm.get_filters(), _vm.get_grid_save_state()) {
          menu_display = _menu_display_vm.safe_create()
       };
 

src/client/spark/Modules/Trading/Fills/FillsWindowFactory.cs

@@ -17,7 +17,7 @@ namespace bts.shell {
       readonly IBus _bus;
       readonly OrdersModel _orders_model;
       readonly UserSettingsHub _settings_hub;
-      /// Fills 'sorting-criterion' settings were compromised a while back (mid-late 2018).
+      /// Fills 'sorting-criteria' settings were compromised a while back (mid-late 2018).
       /// The issue was that, when a column was sorted, its 'sort member path' was assigned to the SortingCriteria.col_name,
       /// rather than the <see cref="Columns"/> enum/id string.
       /// This dictionary serves as a reverse-lookup so the sort member path can be converted to the enum/id string.
@@ -58,7 +58,7 @@ namespace bts.shell {
          _bus.post(SparkTags.ShowWindow, await load(state));
 
       IShellWindow _create(FillsSettings state) {
-         GridSettingsHelper.normalize_sorting_criterion(state.sorting_criterion, _sort_member_to_id);
+         GridSettingsHelper.normalize_sorting_criteria(state.sorting_criteria, _sort_member_to_id);
          var settings_manager = new WindowSettingsManager<GridSettings>(_settings_hub,
             state.grid,
             get: us => us.fills_grid,

src/client/spark/Modules/Trading/Fills/Settings/FillsSettings.cs

@@ -34,9 +34,9 @@ namespace bts.shell.fills {
          this.grid = grid;
       }
 
-      public static GridSettings DefaultGridSettings => GridSettings.Default.with(DefaultColumns.all, DefaultColumns.default_sorting_criterion);
-      public static GridSettings MiniGridSettings => GridSettings.Default.with(DefaultColumns.Mini.all, DefaultColumns.Mini.sorting_criterion);
-      public IReadOnlyList<SortingCriteria> sorting_criterion => _sorting_criteria ?? (_sorting_criteria = DefaultColumns.default_sorting_criterion.ToList());
+      public static GridSettings DefaultGridSettings => GridSettings.Default.with(DefaultColumns.all, DefaultColumns.default_sorting_criteria);
+      public static GridSettings MiniGridSettings => GridSettings.Default.with(DefaultColumns.Mini.all, DefaultColumns.Mini.sorting_criteria);
+      public IReadOnlyList<SortingCriteria> sorting_criteria => _sorting_criteria ?? (_sorting_criteria = DefaultColumns.default_sorting_criteria.ToList());
       public static FillsSettings Default() =>
          new FillsSettings(null, null, new FillsFilterStates(), null);
 
@@ -57,7 +57,7 @@ namespace bts.shell.fills {
          public static GridColumnSettings fill_key => new GridColumnSettings(col_id(Columns.FillKey), DefaultColumnHeaders.FillKey, width: DefaultColumnWidths.FillKey);
          public static GridColumnSettings order_key => new GridColumnSettings(col_id(Columns.OrderKey), DefaultColumnHeaders.OrderKey, width: DefaultColumnWidths.OrderKey);
          public static GridColumnSettings security_key => new GridColumnSettings(col_id(Columns.SecurityKey), DefaultColumnHeaders.SecurityKey, is_visible: false, width: DefaultColumnWidths.SecurityKey);
-         public static IEnumerable<SortingCriteria> default_sorting_criterion {
+         public static IEnumerable<SortingCriteria> default_sorting_criteria {
             get {
                yield return new SortingCriteria(fill_time.id, false);
             }
@@ -96,7 +96,7 @@ namespace bts.shell.fills {
                };
 
             public static IEnumerable<GridColumnSettings> all => DefaultColumns.all.Select(_convert);
-            public static IEnumerable<SortingCriteria> sorting_criterion => default_sorting_criterion.Where(c => _try_get_data(c.col_name, out (bool is_visible, double? _) d) && d.is_visible);
+            public static IEnumerable<SortingCriteria> sorting_criteria => default_sorting_criteria.Where(c => _try_get_data(c.col_name, out (bool is_visible, double? _) d) && d.is_visible);
 
             static bool _try_get_data(string id_str, out (bool is_visible, double? width_override) data) {
                if (Enum.TryParse(id_str, out Columns k) && _mini_cols_data.TryGetValue(k, out data))

src/client/spark/Modules/Trading/Ladder/LadderSettings.cs

@@ -635,8 +635,8 @@ namespace mbts.spark {
          if (s.mini_ob.value == null)
             s.mini_ob = new LadderMiniOrderBookSettings(bts.shell.orderbook.OrderBookStartupData.default_mini_grid.general);
 #pragma warning disable CS0612 // Type or member is obsolete
-         if (s.mini_ob.value.sorting_criterion.Count == 0)
-            s.mini_ob = new LadderMiniOrderBookSettings(s.mini_ob.value.with(sorting_criterion: bts.shell.orderbook.OrderBookStartupData.default_mini_grid.general.sorting_criterion));
+         if (s.mini_ob.value.sorting_criteria.Count == 0)
+            s.mini_ob = new LadderMiniOrderBookSettings(s.mini_ob.value.with(sorting_criteria: bts.shell.orderbook.OrderBookStartupData.default_mini_grid.general.sorting_criteria));
 #pragma warning restore CS0612 // Type or member is obsolete
          s.row_height = LadderRender.measure_row_height(s);
          return s;

src/client/spark/Modules/Trading/Ladder/VM/LadderSettingsVM.cs

@@ -401,7 +401,7 @@ namespace mbts.spark {
             clone = SparkUtils.clone_proto(_current);
 #pragma warning disable CS0612 // Type or member is obsolete
             clone.mini_ob = new LadderMiniOrderBookSettings(_current.mini_ob.value != null ? 
-               mini_ob.create().with(sorting_criterion: _current.mini_ob.value.sorting_criterion) :
+               mini_ob.create().with(sorting_criteria: _current.mini_ob.value.sorting_criteria) :
                mini_ob.create());
 #pragma warning restore CS0612 // Type or member is obsolete
          }

src/client/spark/Modules/Trading/ManualFills/ManualFillsSettings.cs

@@ -8,16 +8,16 @@ namespace bts.shell.manual_fills {
    [ProtoContract]
    class ManualFillsSettings {
       [ProtoMember(1)]
-      readonly SortingCriteria[] _sorting_criterion;
+      readonly SortingCriteria[] _sorting_criteria;
 
       public static ManualFillsSettings Default =>
          new ManualFillsSettings(new[] { new SortingCriteria(nameof(mbts.ui.spark.ManualFillsView.Columns.Security), true) });
 
       public ManualFillsSettings() { }
 
-      public ManualFillsSettings(IEnumerable<SortingCriteria> sorting_criterion) =>
-         _sorting_criterion = sorting_criterion.ToArray();
+      public ManualFillsSettings(IEnumerable<SortingCriteria> sorting_criteria) =>
+         _sorting_criteria = sorting_criteria.ToArray();
 
-      public IReadOnlyList<SortingCriteria> sorting_criterion => _sorting_criterion ?? Array.Empty<SortingCriteria>();
+      public IReadOnlyList<SortingCriteria> sorting_criteria => _sorting_criteria ?? Array.Empty<SortingCriteria>();
    }
 }

src/client/spark/Modules/Trading/ManualFills/ManualFillsWindowFactory.cs

@@ -44,10 +44,10 @@ namespace bts.shell {
             var vm = ManualFillsVM.create(_bus, _orders_model);
             var view = new ManualFillsView { DataContext = vm };
             view.data_grid.Sorting += on_sorting;
-            IReadOnlyList<SortingCriteria> last_sorting_criterion = Array.Empty<SortingCriteria>();
+            IReadOnlyList<SortingCriteria> last_sorting_criteria = Array.Empty<SortingCriteria>();
             using (apply_sort()) {
                var col_sort_tuples =
-                  from sc in settings.sorting_criterion
+                  from sc in settings.sorting_criteria
                   join col in view.data_grid.Columns on sc.col_name equals _col_id(col)
                   select (col, sc);
                foreach (var (col, sc) in col_sort_tuples) {
@@ -65,8 +65,8 @@ namespace bts.shell {
                new SparkCommandCommand("Delete Selected", Icons.Trash, vm.remove_selected_fills_cmd)
             };
             return (view, cmds, get_settings, Disposable.Create(
-               vm.rows_view.subscribe_sorting_criterion(sm => view.data_grid.Columns.TryGetFirst(dc => dc.SortMemberPath == sm, out DataGridColumn match) ? _col_id(match) : null)
-               .Subscribe(sc => last_sorting_criterion = sc),
+               vm.rows_view.subscribe_sorting_criteria(sm => view.data_grid.Columns.TryGetFirst(dc => dc.SortMemberPath == sm, out DataGridColumn match) ? _col_id(match) : null)
+               .Subscribe(sc => last_sorting_criteria = sc),
                vm));
             //
             void on_sorting(object sender, DataGridSortingEventArgs e) {
@@ -102,7 +102,7 @@ namespace bts.shell {
                });
 
             ManualFillsSettings get_settings() =>
-               new ManualFillsSettings(last_sorting_criterion);
+               new ManualFillsSettings(last_sorting_criteria);
          }
       }
 

src/client/spark/Modules/Trading/OrderBook/OrderBookColumns.cs

@@ -39,7 +39,7 @@ namespace mbts.spark {
    }
 
    class OrderBookSortingData : IEquatable<OrderBookSortingData> {
-      public readonly IReadOnlyList<SortingCriteria> sorting_criterion;
+      public readonly IReadOnlyList<SortingCriteria> sorting_criteria;
       public readonly IComparer<OrderBookRowVM> comparer;
       public readonly string desc;
 
@@ -52,13 +52,13 @@ namespace mbts.spark {
             comp_builder.add(Comparer<OrderBookRowVM>.Create((l, r) => l.order_key.CompareTo(r.order_key)));
          }
          comparer = comp_builder.to_comparer();
-         sorting_criterion = column_sorting_hierarchy.Select(col => new SortingCriteria(col.id, col.SortDirection.GetValueOrDefault() == ListSortDirection.Ascending)).ToArray();
-         desc = string.Join(", ", sorting_criterion);
+         sorting_criteria = column_sorting_hierarchy.Select(col => new SortingCriteria(col.id, col.SortDirection.GetValueOrDefault() == ListSortDirection.Ascending)).ToArray();
+         desc = string.Join(", ", sorting_criteria);
       }
 
-      public bool Equals(OrderBookSortingData other) => other != null && EqualityComparer.safe_sequence_equals(sorting_criterion, other.sorting_criterion);
+      public bool Equals(OrderBookSortingData other) => other != null && EqualityComparer.safe_sequence_equals(sorting_criteria, other.sorting_criteria);
       public override bool Equals(object obj) => base.Equals(obj);
-      public override int GetHashCode() => EqualityComparer.aggregate_hash(sorting_criterion);
+      public override int GetHashCode() => EqualityComparer.aggregate_hash(sorting_criteria);
       public override string ToString() => desc;
    }
 
@@ -393,7 +393,7 @@ namespace mbts.spark {
             };
 
          public (FilterStates filters, IReadOnlyList<SortingCriteria> sorting) create() =>
-            (create_filter_states(), get_sorting_data().sorting_criterion);
+            (create_filter_states(), get_sorting_data().sorting_criteria);
 
          public void load_from((FilterStates filters, IReadOnlyList<SortingCriteria> sorting) state) {
             if (state.filters is FilterStates fs) {

src/client/spark/Modules/Trading/OrderBook/OrderBookVM.cs

@@ -606,7 +606,7 @@ namespace mbts.spark {
          _columns.filter_changed -= _on_filter_changed;
          grid_settings_manager.algo_tree_display_mode_changed -= _on_filter_changed;
 #pragma warning disable CS0612 // Type or member is obsolete
-         _columns.load_from((state.filters, (state.orderbook_grid?.general ?? OrderBookStartupData.DefaultGrid.general).sorting_criterion));
+         _columns.load_from((state.filters, (state.orderbook_grid?.general ?? OrderBookStartupData.DefaultGrid.general).sorting_criteria));
 #pragma warning restore CS0612 // Type or member is obsolete
          // resume column filter updates
          _columns.filter_changed += _on_filter_changed;
@@ -739,7 +739,7 @@ namespace mbts.spark {
       static OrderBookFillsGridSettings _get_fills_settings(FillsVM fills_vm) =>
          fills_vm == null ? OrderBookStartupData.DefaultFillsGrid :
             new OrderBookFillsGridSettings {
-               sorting_criterion = fills_vm.get_sorting_criterion().ToList(),
+               sorting_criteria = fills_vm.get_sorting_criteria().ToList(),
                filters = fills_vm.get_filters(),
                general = fills_vm.grid_settings_manager.create()
             };

src/client/spark/Modules/Trading/OrderBook/Settings/OrderBookFillsGridSettings.cs

@@ -12,9 +12,9 @@ namespace bts.shell.orderbook {
       [ProtoMember(2)]
       public FillsFilterStates filters { get; set; }
       [ProtoMember(3)]
-      public List<SortingCriteria> sorting_criterion { get; set; }
+      public List<SortingCriteria> sorting_criteria { get; set; }
 
       public FillsSettings to_startup_data() =>
-         new FillsSettings(null, sorting_criterion, filters, general);
+         new FillsSettings(null, sorting_criteria, filters, general);
    }
 }

src/client/spark/Modules/Trading/OrderBook/Settings/OrderBookGridSettingsManager.cs

@@ -82,9 +82,9 @@ namespace bts.shell.orderbook {
          algo_tree_display_mode = gs.algo_tree_display_mode;
       }
 
-      public OrderBookGridSettings create(IEnumerable<SortingCriteria> sorting_criterion) {
+      public OrderBookGridSettings create(IEnumerable<SortingCriteria> sorting_criteria) {
          var gs = core_manager.create();
-         gs.general = gs.general.with(sorting_criterion: sorting_criterion);
+         gs.general = gs.general.with(sorting_criteria: sorting_criteria);
          gs.algo_tree_display_mode = _algo_tree_display_mode;
          return gs;
       }

src/client/spark/Modules/Trading/OrderBook/Settings/OrderBookSettings.cs

@@ -133,15 +133,15 @@ namespace bts.shell.orderbook {
          get {
             var default_fills = FillsSettings.Default();
             var rv = new OrderBookFillsGridSettings {
-               sorting_criterion = default_fills.sorting_criterion.ToList(),
+               sorting_criteria = default_fills.sorting_criteria.ToList(),
                filters = default_fills.filters,
                general = FillsSettings.MiniGridSettings
             };
             return rv;
          }
       }
-      static GridSettings _default_general_grid => GridSettings.Default.with(DefaultColumns.standard, DefaultColumns.sorting_criterion);
-      public static OrderBookGridSettings default_mini_grid => new OrderBookGridSettings(GridSettings.Default.with(DefaultColumns.mini, DefaultColumns.sorting_criterion)) {
+      static GridSettings _default_general_grid => GridSettings.Default.with(DefaultColumns.standard, DefaultColumns.sorting_criteria);
+      public static OrderBookGridSettings default_mini_grid => new OrderBookGridSettings(GridSettings.Default.with(DefaultColumns.mini, DefaultColumns.sorting_criteria)) {
          algo_tree_display_mode = AlgoTreeDisplayMode.RootAndLeafNodes
       };
 
@@ -179,7 +179,7 @@ namespace bts.shell.orderbook {
          public static GridColumnSettings edit_price => new GridColumnSettings(Columns.EditablePrice.ToString(), DIYGrid.DefaultColumnHeaders.Price, width: DIYGrid.DefaultColumnWidths.MiniOrderBook.EditablePrice);
          public static GridColumnSettings commit => new GridColumnSettings(Columns.Commit.ToString(), width: DIYGrid.DefaultColumnWidths.MiniOrderBook.Commit);
 
-         public static IEnumerable<SortingCriteria> sorting_criterion {
+         public static IEnumerable<SortingCriteria> sorting_criteria {
             get {
                yield return new SortingCriteria(time_created.id, false);
             }

src/client/spark/Modules/Trading/PAndLWindowFactory.cs

@@ -64,9 +64,9 @@ namespace bts.shell {
             this.grid = grid;
          }
 
-         public static GridSettings DefaultGridSettings => GridSettings.Default.with(DefaultColumns.all, DefaultColumns.default_sorting_criterion);
+         public static GridSettings DefaultGridSettings => GridSettings.Default.with(DefaultColumns.all, DefaultColumns.default_sorting_criteria);
 
-         public IReadOnlyList<SortingCriteria> sorting_criterion => _sort_criteria ?? (_sort_criteria = DefaultColumns.default_sorting_criterion.ToList());
+         public IReadOnlyList<SortingCriteria> sorting_criteria => _sort_criteria ?? (_sort_criteria = DefaultColumns.default_sorting_criteria.ToList());
          public static PAndLStartupData Default() =>
             new PAndLStartupData(null, new FilterStates(), pnl_calc_type.midpoint);
 
@@ -100,7 +100,7 @@ namespace bts.shell {
             public static GridColumnSettings pnl_price => new GridColumnSettings(col_id(Columns.PNLPrice), DefaultColumnHeaders.PnLPrice, width: DefaultColumnWidths.PnL_Generic, horizontal_alignment: System.Windows.HorizontalAlignment.Right);
             public static GridColumnSettings has_day_trades => new GridColumnSettings(col_id(Columns.TradedToday), "Traded Today", width: 100, horizontal_alignment: System.Windows.HorizontalAlignment.Center);
 
-            public static IEnumerable<SortingCriteria> default_sorting_criterion {
+            public static IEnumerable<SortingCriteria> default_sorting_criteria {
                get {
                   yield return new SortingCriteria(account.id, true);
                   yield return new SortingCriteria(exchange.id, true);

src/client/spark/Modules/Trading/PNL/PNLWindowFactory.cs

@@ -85,14 +85,14 @@ namespace bts.shell {
             Func<PNLSaveState> get_save_state = () => {
                var cols = cached_columns.ToArray(c => c.create());
                var filters = vm.get_filters_states();
-               var sorting_criterion = vm.sorting_hierarchy.Select(tup => new SortingCriteria(tup.key.ToString(), tup.direction == ListSortDirection.Ascending)).ToArray();
+               var sorting_criteria = vm.sorting_hierarchy.Select(tup => new SortingCriteria(tup.key.ToString(), tup.direction == ListSortDirection.Ascending)).ToArray();
                var calc_type = vm.calculation_type;
                var state = settings_manager.instance_settings;
                if (state == null) {
                   // don't use defaults if the user manipulated the window state outside of the settings dialog (e.g., resized column(s) via drag, or changed sort/filter)
                   var defaults = settings_manager.default_settings;
                   if (calc_type == defaults.calculation_type &&
-                     defaults.sorting_criterion.SequenceEqual(sorting_criterion) &&
+                     defaults.sorting_criteria.SequenceEqual(sorting_criteria) &&
                      defaults.grid.columns.SequenceEqual(cols) && defaults.filters.safe_equals(filters)) {
                      // the user's current state still matches the defaults (i.e., no outside manipulation was performed); return null so this window will use the latest default settings when restored
                      return new PNLSaveState { use_defaults = true, settings = null };
@@ -101,7 +101,7 @@ namespace bts.shell {
                }
                // assign latest values, as they may have be modified outside of the settings dialog (in which case the settings manager would be out of date)
                state = state.with(
-                  sorting_criterion,
+                  sorting_criteria,
                   vm.anchors,
                   filters,
                   state.grid.with(columns: cols, background: vm.grid_background_color.rgb_color()),

src/client/spark/Modules/Trading/PNL/Settings/PNLSettings.cs

@@ -80,7 +80,7 @@ namespace bts.shell.pnl {
          };
 
       [ProtoMember(1)]
-      SortingCriteria[] _sorting_criterion;
+      SortingCriteria[] _sorting_criteria;
       [ProtoMember(5)]
       Columns[] _anchors;
       [ProtoMember(7)]
@@ -106,7 +106,7 @@ namespace bts.shell.pnl {
 
       public static PNLSettings Default =>
          new PNLSettings {
-            _sorting_criterion = new[] {
+            _sorting_criteria = new[] {
                new SortingCriteria(nameof(Columns.Account), true),
                new SortingCriteria(nameof(Columns.Security), true)
             },
@@ -154,7 +154,7 @@ namespace bts.shell.pnl {
       public static GridSettings DefaultGridSettings =>
          GridSettings.Default.with(
             DefaultColumns.all,
-            DefaultColumns.default_sorting_criterion,
+            DefaultColumns.default_sorting_criteria,
             enable_background_color: true);
 
       public static fills.FillsSettings DefaultAuxiliaryFills {
@@ -289,8 +289,8 @@ namespace bts.shell.pnl {
       public PNLCellAppearance header_defaults => header_cell_appearance.to_appearance().merge(grid_defaults);
       public IReadOnlyList<PNLAnimationTriggerData> header_row_animations => _header_row_animations ?? (_header_row_animations = default_header_row_animations.ToArray());
       //
-      public IReadOnlyList<SortingCriteria> sorting_criterion =>
-         _sorting_criterion ?? (_sorting_criterion = DefaultColumns.default_sorting_criterion.ToArray());
+      public IReadOnlyList<SortingCriteria> sorting_criteria =>
+         _sorting_criteria ?? (_sorting_criteria = DefaultColumns.default_sorting_criteria.ToArray());
 
       PNLCellAppearanceProto _grid_cell_appearance => _grid_cell_appearance_backing ?? (
          _grid_cell_appearance_backing = new PNLCellAppearanceProto {
@@ -305,7 +305,7 @@ namespace bts.shell.pnl {
          });
 
       public PNLSettings with(
-         IEnumerable<SortingCriteria> sorting_criterion = null,
+         IEnumerable<SortingCriteria> sorting_criteria = null,
          IEnumerable<Columns> anchors = null,
          FilterStates filters = null,
          GridSettings grid = null,
@@ -323,7 +323,7 @@ namespace bts.shell.pnl {
             header_row_display = header_row_display ?? this.header_row_display,
             // row operators (anchors, sorting, filters)
             _anchors = (anchors ?? _anchors.empty_if_null()).ToArray(),
-            _sorting_criterion = (sorting_criterion ?? _sorting_criterion.empty_if_null()).ToArray(),
+            _sorting_criteria = (sorting_criteria ?? _sorting_criteria.empty_if_null()).ToArray(),
             filters = filters ?? this.filters,
             // cell appearance (group/header)
             _group_background_colors = _group_background_colors?.ToList(),
@@ -349,7 +349,7 @@ namespace bts.shell.pnl {
          data_formatting.safe_equals(other.data_formatting) &&
          // row operators (anchors, sorting, filters)
          anchors.SequenceEqual(other.anchors) &&
-         sorting_criterion.SequenceEqual(other.sorting_criterion) &&
+         sorting_criteria.SequenceEqual(other.sorting_criteria) &&
          filters.safe_equals(other.filters) &&
          // cell appearance (group/header)
          group_background_colors.SequenceEqual(other.group_background_colors) &&
@@ -431,7 +431,7 @@ namespace bts.shell.pnl {
          public static GridColumnSettings settlement_price => new GridColumnSettings(nameof(Columns.SettlementPrice), DefaultColumnHeaders.Settlement, false, width: DefaultColumnWidths.Settlement, horizontal_alignment: HorizontalAlignment.Right);
          public static GridColumnSettings pnl_price => new GridColumnSettings(nameof(Columns.PNLPrice), DefaultColumnHeaders.PnLPrice, width: DefaultColumnWidths.Price, horizontal_alignment: HorizontalAlignment.Right);
 
-         public static IEnumerable<SortingCriteria> default_sorting_criterion {
+         public static IEnumerable<SortingCriteria> default_sorting_criteria {
             get {
                yield return new SortingCriteria(account.id, true);
                yield return new SortingCriteria(security.id, true);

src/client/spark/Modules/Trading/PNL/VM/PNLVM.cs

@@ -118,7 +118,15 @@ namespace bts.shell.pnl {
             ).FilterWithRaw(filter_src, PNLRowData.key_fn, null)
             .OnDispatcher()
             .Subscribe(_update),
-            _symbols_source(pnl_source).OnDispatcher().Subscribe(symbol_filter_items_observer),
+            // Note: the symbol filter items don't really need to be an IObservable
+            // (the symbol items used to be extracted from the IObservable pnl_source).
+            // It is only an IObservable now due to legacy; the filter was designed to observe incremental updates.
+            // This is can be easily changed if need be.
+            Observable.Return(
+               TableUpdate<string, string>.mk_empty(sym => sym).with_added(
+               SecurityHelper.get_all_display_symbols()))
+            .OnDispatcher()
+            .Subscribe(symbol_filter_items_observer),
             Disposable.Create(() => {
                foreach (var f in _all_filters)
                   f.filter_changed -= _refresh_filter.execute;
@@ -369,7 +377,7 @@ namespace bts.shell.pnl {
          }
          anchors.sync_with(settings.anchors);
          header_row_display = settings.header_row_display;
-         sorting_hierarchy = DIYGridSortHelper.convert_sorting_criterion<ColumnKeys>(settings.sorting_criterion).ToList();
+         sorting_hierarchy = DIYGridSortHelper.convert_sorting_criteria<ColumnKeys>(settings.sorting_criteria).ToList();
          // group background colors
          _group_background_converter = new AlternationConverter();
          _group_background_converter.Values.AddRange(settings.group_background_colors.Select(c => c.argb_color()));

src/client/spark/Trades/TradesSource.cs

@@ -44,17 +44,17 @@ namespace mbts.spark {
    }
 
    static class TradesSource {
-      public static IEnumerable<Product> aggregate_security_criteria(IEnumerable<SecurityImmutable> securities, IEnumerable<SecurityCriteria> security_criterion) =>
-         securities.Where(s => security_criterion.Any(sc => ContractPickerModel.security_in_criteria(sc, s)))
+      public static IEnumerable<Product> aggregate_security_criteria(IEnumerable<SecurityImmutable> securities, IEnumerable<SecurityCriteria> security_criteria) =>
+         securities.Where(s => security_criteria.Any(sc => ContractPickerModel.security_in_criteria(sc, s)))
          .Select(Product.from_security)
          .Distinct();
 
-      public static IObservable<IReadOnlyList<TradeInfo>> create(MDConsumer consumer, IObservable<IReadOnlyDictionary<uint, SecurityImmutable>> security_map, IObservable<IEnumerable<SecurityCriteria>> security_criterion, TimeSpan poll_interval) =>
-         security_criterion.CombineLatest(security_map, (criterion, map) => (criterion, map))
+      public static IObservable<IReadOnlyList<TradeInfo>> create(MDConsumer consumer, IObservable<IReadOnlyDictionary<uint, SecurityImmutable>> security_map, IObservable<IEnumerable<SecurityCriteria>> security_criteria, TimeSpan poll_interval) =>
+         security_criteria.CombineLatest(security_map, (criterion, map) => (criterion, map))
             .Scan((channels: ImmutableDictionary<Product, ChannelConsumer>.Empty, active: new List<ChannelConsumer>(0)), (channel_data, data) => {
-               var (criterion, map) = data;
+               var (criteria, map) = data;
                var (channels, active) = channel_data;
-               var products = aggregate_security_criteria(map.Values, criterion);
+               var products = aggregate_security_criteria(map.Values, criteria);
                active = new List<ChannelConsumer>();
                foreach (var p in products) {
                   if (!channels.TryGetValue(p, out var c)) {

src/client/spark/view/Controls/DIYGrid/DIYGrid.cs

@@ -68,8 +68,8 @@ namespace mbts.ui.controls {
          .to_comparer();
       }
 
-      public static IEnumerable<(TKey key, ListSortDirection direction)> convert_sorting_criterion<TKey>(IEnumerable<SortingCriteria> sorting_criterion) where TKey : struct {
-         foreach (var sc in sorting_criterion) {
+      public static IEnumerable<(TKey key, ListSortDirection direction)> convert_sorting_criteria<TKey>(IEnumerable<SortingCriteria> sorting_criteria) where TKey : struct {
+         foreach (var sc in sorting_criteria) {
             if (Enum.TryParse(sc.col_name, false, out TKey key))
                yield return (key, sc.direction());
          }

src/client/spark/view/Controls/DIYGrid/Settings/GridSettings.cs

@@ -76,9 +76,9 @@ namespace mbts.ui.settings {
       // columns
       [ProtoMember(6)]
       List<GridColumnSettings> _columns;
-      // sorting criterion
+      // sorting criteria
       [ProtoMember(7)]
-      List<SortingCriteria> _sorting_criterion;
+      List<SortingCriteria> _sorting_criteria;
       // background
       [ProtoMember(8)]
       [DefaultValue(_default_background)]
@@ -103,7 +103,7 @@ namespace mbts.ui.settings {
          uint font_color = _default_font_color,
          ColorOpacityProto? selection_highlight = null,
          IEnumerable<GridColumnSettings> columns = null,
-         IEnumerable<SortingCriteria> sorting_criterion = null,
+         IEnumerable<SortingCriteria> sorting_criteria = null,
          uint background = _default_background,
          bool enable_background_color = _default_enable_background_color) {
          //
@@ -113,7 +113,7 @@ namespace mbts.ui.settings {
          _font_weight = (ushort)font_weight.ToOpenTypeWeight();
          _selection_highlight = selection_highlight ?? new ColorOpacityProto(0, 1);
          _columns = new List<GridColumnSettings>(columns.empty_if_null());
-         _sorting_criterion = new List<SortingCriteria>(sorting_criterion.empty_if_null());
+         _sorting_criteria = new List<SortingCriteria>(sorting_criteria.empty_if_null());
          _background = background;
          _enable_background_color = enable_background_color;
       }
@@ -127,15 +127,15 @@ namespace mbts.ui.settings {
       public uint background_color => _background;
       public bool enable_background_color => _enable_background_color;
       public IReadOnlyList<GridColumnSettings> columns => _columns ?? (_columns = new List<GridColumnSettings>(0));
-      [Obsolete] // TODO: remove sorting_criterion from GridSettings entirely. This should be part of IShellWindow's StartupData, since it is an instance-specific setting, and prob not part of the shared defaults
-      public IReadOnlyList<SortingCriteria> sorting_criterion => _sorting_criterion ?? (_sorting_criterion = new List<SortingCriteria>(0));
+      [Obsolete] // TODO: remove sorting_criteria from GridSettings entirely. This should be part of IShellWindow's StartupData, since it is an instance-specific setting, and prob not part of the shared defaults
+      public IReadOnlyList<SortingCriteria> sorting_criteria => _sorting_criteria ?? (_sorting_criteria = new List<SortingCriteria>(0));
 
       public static GridSettings get_default() =>
          new GridSettings(_default_font_family, _default_font_size, FontWeights.Normal, _default_font_color, new ColorOpacityProto(Colors.MediumSlateBlue, 0.4));
 
       public GridSettings with(
          IEnumerable<GridColumnSettings> columns = null,
-         IEnumerable<SortingCriteria> sorting_criterion = null,
+         IEnumerable<SortingCriteria> sorting_criteria = null,
          string font_family = null,
          double font_size = double.NaN,
          uint? background = null,
@@ -147,7 +147,7 @@ namespace mbts.ui.settings {
             _font_color,
             _selection_highlight,
             columns ?? _columns,
-            sorting_criterion ?? _sorting_criterion,
+            sorting_criteria ?? _sorting_criteria,
             background ?? _background,
             enable_background_color ?? _enable_background_color);
 
@@ -164,7 +164,7 @@ namespace mbts.ui.settings {
          _enable_background_color == other._enable_background_color &&
          EqualityComparer.safe_sequence_equals(columns, other.columns) &&
 #pragma warning disable CS0612 // Type or member is obsolete
-         EqualityComparer.safe_sequence_equals(sorting_criterion, other.sorting_criterion);
+         EqualityComparer.safe_sequence_equals(sorting_criteria, other.sorting_criteria);
 #pragma warning restore CS0612 // Type or member is obsolete
 
       public override bool Equals(object obj) =>
@@ -181,7 +181,7 @@ namespace mbts.ui.settings {
             _enable_background_color.GetHashCode(),
             EqualityComparer.safe_aggregate_hash(columns),
 #pragma warning disable CS0612 // Type or member is obsolete
-            EqualityComparer.safe_aggregate_hash(sorting_criterion));
+            EqualityComparer.safe_aggregate_hash(sorting_criteria));
 #pragma warning restore CS0612 // Type or member is obsolete
    }
-}
+}

src/client/spark/view/Controls/DIYGrid/Settings/GridSettingsHelper.cs

@@ -54,14 +54,14 @@ namespace mbts.ui.settings {
       public static string fmt_col_id<TColKey>(TColKey key) where TColKey : struct =>
          key.ToString();
 
-      public static void normalize_sorting_criterion<TColKey>(IEnumerable<SortingCriteria> sorting_criterion, IReadOnlyDictionary<string, TColKey> sort_member_to_id) where TColKey : struct =>
-         normalize_sorting_criterion(sorting_criterion, new Func<string, TColKey?>[] {
+      public static void normalize_sorting_criteria<TColKey>(IEnumerable<SortingCriteria> sorting_criteria, IReadOnlyDictionary<string, TColKey> sort_member_to_id) where TColKey : struct =>
+         normalize_sorting_criteria(sorting_criteria, new Func<string, TColKey?>[] {
             parse_col_id<TColKey>,
             col_name => sort_member_to_id.TryGetValue(col_name, out var k) ? k : (TColKey?)null
          });
 
-      public static void normalize_sorting_criterion<TColKey>(IEnumerable<SortingCriteria> sorting_criterion, IEnumerable<Func<string, TColKey?>> conversion_dels) where TColKey : struct {
-         foreach (var sc in sorting_criterion) {
+      public static void normalize_sorting_criteria<TColKey>(IEnumerable<SortingCriteria> sorting_criteria, IEnumerable<Func<string, TColKey?>> conversion_dels) where TColKey : struct {
+         foreach (var sc in sorting_criteria) {
             sc.col_name = conversion_dels
                .Select(del => del(sc.col_name))
                .FirstOrDefault(k => k.HasValue)?.ToString() ?? sc.col_name;

src/client/spark/view/Controls/DIYGrid/Utils/DIYGridRowsManager.cs

@@ -114,7 +114,7 @@ namespace mbts.ui.controls {
       public Func<T, bool> filter { get; private set; }
 
       public TFiltersState get_filters() => _filters.create();
-      public IEnumerable<SortingCriteria> get_sorting_criterion() => _sorting.create();
+      public IEnumerable<SortingCriteria> get_sorting_criteria() => _sorting.create();
 
       public void on_sorting(DIYGridSortingEventArgs e) => _sorting.on_sorting(e);
       public void on_settings(TFiltersState filters, IEnumerable<SortingCriteria> sorting) {

src/client/spark/view/Controls/DIYGrid/Utils/DIYGridSortManager.cs

@@ -54,13 +54,13 @@ namespace mbts.ui.controls {
          ).to_comparer();
       }
 
-      public void load_from(IEnumerable<SortingCriteria> sorting_criterion) {
+      public void load_from(IEnumerable<SortingCriteria> sorting_criteria) {
          var sort_member_to_id = _map
             .Where(kv => !string.IsNullOrEmpty(kv.Value.col.sort_member_path))
             .Distinct()
             .ToDictionary(kv => kv.Value.col.sort_member_path, kv => kv.Key);
-         GridSettingsHelper.normalize_sorting_criterion(sorting_criterion, sort_member_to_id);
-         _on_settings(sorting_criterion
+         GridSettingsHelper.normalize_sorting_criteria(sorting_criteria, sort_member_to_id);
+         _on_settings(sorting_criteria
             .Select(sc => (GridSettingsHelper.parse_col_id<TColKey>(sc.col_name), sc.is_ascending ? ListSortDirection.Ascending : ListSortDirection.Descending))
             .Where(t => t.Item1.HasValue)
             .Select(t => (t.Item1.Value, t.Item2)));

src/client/spark/view/Extensions/WPFExtensions.cs

@@ -372,11 +372,11 @@ namespace mbts.ui {
          on sd.PropertyName equals col.path
          select new SortingCriteria(col.id, sd.Direction == ListSortDirection.Ascending);
 
-      public static IEnumerable<SortDescription> get_sort_descriptions(this IEnumerable<SortingCriteria> sorting_criterion, IEnumerable<DataGridColumn> columns) =>
-         get_sort_descriptions(sorting_criterion, columns.Select(c => (controls.DataGridEx.GetCellKey(c)?.ToString(), c.SortMemberPath)));
+      public static IEnumerable<SortDescription> get_sort_descriptions(this IEnumerable<SortingCriteria> sorting_criteria, IEnumerable<DataGridColumn> columns) =>
+         get_sort_descriptions(sorting_criteria, columns.Select(c => (controls.DataGridEx.GetCellKey(c)?.ToString(), c.SortMemberPath)));
 
-      public static IEnumerable<SortDescription> get_sort_descriptions(this IEnumerable<SortingCriteria> sorting_criterion, IEnumerable<(string id, string path)> columns) =>
-         from sc in sorting_criterion
+      public static IEnumerable<SortDescription> get_sort_descriptions(this IEnumerable<SortingCriteria> sorting_criteria, IEnumerable<(string id, string path)> columns) =>
+         from sc in sorting_criteria
          join col in columns
          on sc.col_name equals col.id
          select new SortDescription(col.path, sc.direction());
@@ -384,9 +384,9 @@ namespace mbts.ui {
       /// <summary>
       /// Converts each <see cref="SortingCriteria"/> into a <see cref="SortDescription"/> and assigns the result to <paramref name="collection_view"/>.SortDescriptions.
       /// </summary>
-      public static void set_sort_descriptions(this ICollectionView collection_view, IEnumerable<SortingCriteria> sorting_criterion, ObservableCollection<controls.DIYGrid.ColumnBase> columns) {
+      public static void set_sort_descriptions(this ICollectionView collection_view, IEnumerable<SortingCriteria> sorting_criteria, ObservableCollection<controls.DIYGrid.ColumnBase> columns) {
          using (collection_view.DeferRefresh()) {
-            collection_view.SortDescriptions.SetItems(sorting_criterion.empty_if_null()
+            collection_view.SortDescriptions.SetItems(sorting_criteria.empty_if_null()
                .Select(sc => new SortDescription(
                   columns.FirstOrDefault(c => string.Equals(c.id, sc.col_name, StringComparison.CurrentCultureIgnoreCase))?.sort_member_path,
                   sc.is_ascending ? ListSortDirection.Ascending : ListSortDirection.Descending))
@@ -394,18 +394,18 @@ namespace mbts.ui {
          }
       }
 
-      public static IObservable<IReadOnlyList<SortingCriteria>> subscribe_sorting_criterion(this ICollectionView collection_view, Func<string, string> sort_member_to_id) =>
+      public static IObservable<IReadOnlyList<SortingCriteria>> subscribe_sorting_criteria(this ICollectionView collection_view, Func<string, string> sort_member_to_id) =>
          Observable.Create<IReadOnlyList<SortingCriteria>>(o => {
             INotifyCollectionChanged notification_src = collection_view.SortDescriptions;
             IList<SortDescription> sort_descriptions = collection_view.SortDescriptions;
-            var sorting_criterion = sort_descriptions.Select(to_criteria).ToList();
+            var sorting_criteria = sort_descriptions.Select(to_criteria).ToList();
             notification_src.CollectionChanged += on_sort_descriptions_changed;
-            o.OnNext(sorting_criterion);
+            o.OnNext(sorting_criteria);
             return Disposable.Create(dispose);
             // local methods
             void on_sort_descriptions_changed(object sender, NotifyCollectionChangedEventArgs e) {
-               CollectionHelper.reflect_change(sorting_criterion, collection_view.SortDescriptions, to_criteria, null, e);
-               o.OnNext(sorting_criterion);
+               CollectionHelper.reflect_change(sorting_criteria, collection_view.SortDescriptions, to_criteria, null, e);
+               o.OnNext(sorting_criteria);
             }
             SortingCriteria to_criteria(SortDescription sd) => new SortingCriteria(sort_member_to_id(sd.PropertyName), sd.Direction == ListSortDirection.Ascending);
             void dispose() => notification_src.CollectionChanged -= on_sort_descriptions_changed;

src/client/spark/view/Spark/PAndL/PAndLVM.cs

@@ -169,7 +169,7 @@ namespace mbts.spark {
          }
 
          // restore sort state or supply default value
-         pnl_view.set_sort_descriptions(startup_data.sorting_criterion, columns);
+         pnl_view.set_sort_descriptions(startup_data.sorting_criteria, columns);
 
          var col_settings_flags = new Dictionary<string, GridColumnSettingsFeatureFlags> {
             { Columns.StartPNL.ToString(), GridColumnSettingsFeatureFlags.ImmutableFontColor },

src/client/spark_api/security/SecurityExtensions.cs

@@ -11,5 +11,8 @@ namespace bts.api {
             default: return SecurityType.Unset;
          }
       }
+
+      public static string display_symbol(this SecurityImmutable security) =>
+         SecurityHelper.get_display_symbol(security);
    }
 }

src/client/spark_api/security/SecurityHelper.cs

@@ -1,10 +1,24 @@
-using System;
+using mbts.co2;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using static bts.api.Security;
 
 namespace bts.api {
    internal static class SecurityHelper {
+      public static IEnumerable<string> get_all_display_symbols() =>
+         get_all_display_symbols(UserSymbol.get_all().Select(usym => usym.symbol));
+
+      public static IEnumerable<string> get_all_display_symbols(IEnumerable<string> system_symbols) {
+         // todo: actual impl
+         return system_symbols;
+      }
+
+      public static string get_display_symbol(SecurityImmutable security) {
+         // todo: actual impl
+         return security.Symbol;
+      }
+
       public static IEnumerable<FutureLeg> get_flat_future_legs(SecurityImmutable sec) {
          switch (sec.ContractCase) {
             case ContractOneofCase.Spread: return _get_flat_future_legs(sec.Spread.Legs, 1);