Add test for subclass of mp_table_subclass.

Document limitation of table nesting due to Octave bug.

lib/mp_table_subclass.m

@@ -21,15 +21,20 @@
 % The class of the contained table object is either :class:`table` or mp_table
 % and is determined by mp_table_class.
 %
-% .. admonition:: Limitation
+% .. admonition:: Limitations
 %
-%   In MATLAB, when nesting an mp_table_subclass object within another
-%   mp_table_subclass object, one cannot use multi-level indexing directly.
-%   E.g. If ``T2`` is a variable in ``T1`` and ``x`` is a variable in ``T2``,
-%   attempting ``x = T1.T2.x`` will result in an error. The indexing must
-%   be done in multiple steps ``T2 = T1.T2; x = T2.x``. Note: This only
-%   applies to MATLAB, where the contained table is a :class:`table`. It works
-%   just fine in Octave, where the contained table is an :class:`mp_table`.
+%   1. The Octave bug mentioned above also affects tables that inherit from
+%      mp_table_subclass. That is, such tables can be nested inside tables
+%      of type :class:`table` or mp_table, but not inside tables that are
+%      or inherit from mp_table_subclass.
+%   2. In MATLAB, when nesting an mp_table_subclass object within another
+%      mp_table_subclass object, one cannot use multi-level indexing directly.
+%      E.g. If ``T2`` is a variable in ``T1`` and ``x`` is a variable in
+%      ``T2``, attempting ``x = T1.T2.x`` will result in an error. The
+%      indexing must be done in multiple steps ``T2 = T1.T2; x = T2.x``.
+%      Note: This only applies to MATLAB, where the contained table is a
+%      :class:`table`. It works just fine in Octave, where the contained
+%      table is an :class:`mp_table`.
 %
 % .. important::
 %

lib/t/mp_foo_table.m

@@ -0,0 +1,16 @@
+classdef mp_foo_table < mp_table_subclass
+
+%   MATPOWER
+%   Copyright (c) 2023, Power Systems Engineering Research Center (PSERC)
+%   by Ray Zimmerman, PSERC Cornell
+%
+%   This file is part of MATPOWER.
+%   Covered by the 3-clause BSD License (see LICENSE file for details).
+%   See https://matpower.org for more info.
+
+    methods
+        function obj = mp_foo_table(varargin)
+            obj@mp_table_subclass(varargin{:});
+        end
+    end     %% methods
+end         %% classdef

lib/t/t_mp_table.m

@@ -21,8 +21,8 @@
 end
 
 skip_tests_for_tablicious = 1;
-table_classes = {@mp_table, @mp_table_subclass};
-class_names = {'mp_table', 'mp_table_subclass'};
+table_classes = {@mp_table, @mp_table_subclass, @mp_foo_table};
+class_names = {'mp_table', 'mp_table_subclass', 'mp_foo_table'};
 if have_feature('table')
     table_classes = {@table, table_classes{:}};
     class_names = {'table', class_names{:}};
@@ -71,8 +71,12 @@
     t_is(size(T, 2), 6, 12, [t 'sz = size(T, 2)']);
     [nr, nz] = size(T);
     t_is([nr, nz], [6 6], 12, [t '[nr, nz] = size(T)']);
-    t_ok(isequal(T.Properties.VariableNames, ...
-        {'var1', 'var2', 'var3', 'var4', 'Var5', 'var6'}), [t 'VariableNames'] );
+    if isa(T, 'mp_foo_table')
+        t_skip(1, 'constructor does not capture var names');
+    else
+        t_ok(isequal(T.Properties.VariableNames, ...
+            {'var1', 'var2', 'var3', 'var4', 'Var5', 'var6'}), [t 'VariableNames'] );
+    end
     t_ok(isempty(T.Properties.RowNames), [t 'RowNames'] );
     t_ok(isequal(T.Properties.DimensionNames, {'Row', 'Variables'}), ...
         [t 'DimensionNames'] );
@@ -548,31 +552,36 @@
     for k2 = 1:nc
         nested_table_class = table_classes{k2};
         nstcls = upper(class_names{k2});
-    
+
         t = sprintf('%s . %s : nested tables : ', cls, nstcls);
         T1 = nested_table_class([1;2;3],[4;5;6]);
         T2 = nested_table_class({'one';'two';'three'},{'four';'five';'six'});
-        T3 = table_class([10;20;30],{'uno';'dos';'tres'}, T1, T2, ...
-            'VariableNames', {'v1', 'v2', 'T1', 'T2'});
-        t_ok(isequal(T3.T1, T1), [t 'T.T1 == T1']);
-        t_ok(isequal(T3.T2, T2), [t 'T.T2 == T2']);
-        if have_feature('matlab') && isa(T1, 'mp_table_subclass') && ...
-                                     isa(T3, 'mp_table_subclass')
-            t_skip(4, 'multiple indexing of nested mp_table_subclasses');
-        else
-            t_ok(isequal(T3.T1([1;3], :), T1([1;3], :)), [t 'T.T1(ii, :) == T1(ii, :)']);
-            t_ok(isequal(T3.T2([1;3], :), T2([1;3], :)), [t 'T.T2(ii, :) == T2(ii, :)']);
-            t_ok(isequal(T3.T1.Var1, T1.Var1), [t 'T.T1.Var1 == T1.Var1']);
-            t_ok(isequal(T3.T2.Var2([1;3], :), T2.Var2([1;3], :)), [t 'T.T2.Var2(ii) == T.T2.Var2(ii)']);
-        end
-        %% check for Octave trouble in subsref
-        if (skip_oct_tab && isa(T3, 'table')) || skip_oct_tab2
-            t_skip(2, 'mp_table_subclass does not handle this yet');
+        if have_feature('octave') && isa(T, 'mp_table_subclass') && ...
+                                     isa(T1, 'mp_foo_table')
+            t_skip(8, 'avoid https://savannah.gnu.org/bugs/index.php?65037');
         else
-            T4 = T3(:, :);
-            T5 = T3([1;2;3], :);
-            t_ok(isequal(T3, T4), [t 'T == T(:, :))']);
-            t_ok(isequal(T3, T5), [t 'T == T(ii, :))']);
+            T3 = table_class([10;20;30],{'uno';'dos';'tres'}, T1, T2, ...
+                'VariableNames', {'v1', 'v2', 'T1', 'T2'});
+            t_ok(isequal(T3.T1, T1), [t 'T.T1 == T1']);
+            t_ok(isequal(T3.T2, T2), [t 'T.T2 == T2']);
+            if have_feature('matlab') && isa(T1, 'mp_table_subclass') && ...
+                                         isa(T3, 'mp_table_subclass')
+                t_skip(4, 'multiple indexing of nested mp_table_subclasses');
+            else
+                t_ok(isequal(T3.T1([1;3], :), T1([1;3], :)), [t 'T.T1(ii, :) == T1(ii, :)']);
+                t_ok(isequal(T3.T2([1;3], :), T2([1;3], :)), [t 'T.T2(ii, :) == T2(ii, :)']);
+                t_ok(isequal(T3.T1.Var1, T1.Var1), [t 'T.T1.Var1 == T1.Var1']);
+                t_ok(isequal(T3.T2.Var2([1;3], :), T2.Var2([1;3], :)), [t 'T.T2.Var2(ii) == T.T2.Var2(ii)']);
+            end
+            %% check for Octave trouble in subsref
+            if (skip_oct_tab && isa(T3, 'table')) || skip_oct_tab2
+                t_skip(2, 'mp_table_subclass does not handle this yet');
+            else
+                T4 = T3(:, :);
+                T5 = T3([1;2;3], :);
+                t_ok(isequal(T3, T4), [t 'T == T(:, :))']);
+                t_ok(isequal(T3, T5), [t 'T == T(ii, :))']);
+            end
         end
     end
 end