all_opts__.m

% Copyright (C) 2009 VZLU Prague
%
% This file is part of Octave.
%
% Octave is free software; you can redistribute it and/or modify it
% under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 3 of the License, or (at
% your option) any later version.
%
% Octave is distributed in the hope that it will be useful, but
% WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
% General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with Octave; see the file COPYING.  If not, see
% <http://www.gnu.org/licenses/>.

% -*- texinfo -*-
% @deftypefn {Function File} {@var{names} =} __all_opts__ (@dots{})
% Undocumented internal function.
% @end deftypefn

% Query all options from all known optimization functions and return a
% list of possible values.

function names = all_opts__ (varargin)

  % persistent saved_names = {};
  persistent saved_names;
  % saved_names = {};

  % do not clear this function
  mlock ();

  % guard against recursive calls.
%  persistent recursive = false;
  persistent recursive;
  % recursive = false;

  if (recursive)
    names = {};
  elseif (nargin == 0)
    names = saved_names;
  else
    % query all options from all known functions. These will call optimset,
    % which will in turn call us, but we won't answer.
    recursive = true;
    names = saved_names;
    for i = 1:nargin
      try
        opts = optimset (varargin{i});
        fn = fieldnames (opts).';
        names = [names, fn];
      catch
        % throw the error as a warning.
        warning (lasterr ());
      end
    end
    names = unique (names);
    lnames = unique (tolower (names));
    if (length (lnames) < length (names))
      % This is bad.
      error ('all_opts__: duplicate options with inconsistent case');
    end
    saved_names = names;
    recursive = false;
  end

end