%!demo
%! ## `lt` (the `<` operator) ranks values by category order, so it needs an
%! ## *ordinal* array.  It compares against a category name or another ordinal
%! ## array.
%!
%! C = categorical ({'M'; 'S'; 'L'; 'M'}, {'S', 'M', 'L'}, 'Ordinal', true)
%!
%! ## Which sizes are strictly smaller than `L`?
%! C < 'L'
%!
%! ## `>`, `<=` and `>=` behave the same way; the same test on a nominal array
%! ## would raise an error, because unordered categories cannot be ranked.
