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+## Copyright (C) 2008 David Bateman
+##
+## 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} {} refreshdata ()
+## @deftypefnx {Function File} {} refreshdata (@var{h})
+## @deftypefnx {Function File} {} refreshdata (@var{h}, @var{ws})
+## Evaluates any datasource properties of the current figure and updates
+## the corresponding data. If call with one or more arguments @var{h} is
+## a scalar or array of figure handles which to refresh. The data
+## sources are by default evaluated in the "base" workspace but can also
+## be set in the "caller" workspace.
+##
+## An example of the use of refreshdata is
+##
+## @example
+## @group
+## x = 0:0.1:10;
+## y = sin (x);
+## plot (x, y, "ydatasource", "y");
+## for i = 1 : 100
+##   pause(0.1)
+##   y = sin (x + 0.1 * i);
+##   refreshdata();
+## endfor
+## @end group
+## @end example
+## 
+## @seealso{linkdata}
+## @end deftypefn
+
+function refreshdata (h, ws)
+
+  if (nargin == 0)
+    h = gcf ();
+    ws = "base";
+  else
+    if (iscell (h))
+      h = [h{:}];
+    endif
+    if (!all (ishandle (h)) || !all (strcmp (get (h, "type"), "figure")))
+      error ("refreshdata: expecting a list of figure handles");
+    endif
+    if (nargin < 2)
+      ws = "base";
+    else
+      if (!ischar (ws) || !(strcmpi (ws, "base") || strcmpi (ws, "caller")))
+	error ("refreshdata: expecting workspace to be \"base\" or ""caller\"");
+      else
+	ws = tolower (ws);
+      endif
+    endif
+  endif
+
+  h = findall (h);
+  objs = [];
+  props = {};
+
+  for i = 1 : numel (h)
+    obj = get (h (i));
+    fldnames = fieldnames (obj);
+    m = regexpi (fieldnames(obj), "^.datasource$", "match");
+    idx = cellfun (@(x) !isempty(x), m);
+    if (any (idx))
+      props = [props; {cell2mat(m(idx))}];
+      objs  = [objs ; h(i)];
+    endif
+  endfor
+
+  for i = 1 : length (objs)
+    for j = 1 : length (props {i})
+      expr = get (objs(i), props{i}{j});
+      if (!isempty (expr))
+	val = evalin (ws, expr);
+	prop =  props{i}{j}(1:end-6);
+        if (! isequal (get (objs(i), prop), val))
+	  set (objs(i), props{i}{j}(1:end-6), val);
+        endif
+      endif
+    endfor
+  endfor
+endfunction
+
+%!demo
+%! x = 0:0.1:10;
+%! y = sin (x);
+%! plot (x, y, "ydatasource", "y");
+%! for i = 1 : 100
+%!   pause(0.1)
+%!   y = sin (x + 0.1 * i);
+%!   refreshdata();
+%! endfor