--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/@pyobject/pyobject.m	Thu May 26 11:35:20 2016 -0700
@@ -0,0 +1,135 @@
+%% Copyright (C) 2016 Colin B. Macdonald
+%%
+%% This file is part of PyTave.
+%%
+%% OctSymPy 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.
+%%
+%% This software 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 this software; see the file COPYING.
+%% If not, see <http://www.gnu.org/licenses/>.
+
+%% -*- texinfo -*-
+%% @documentencoding UTF-8
+%% @defun  pyobject (@var{s})
+%% Wrap a Python object.
+%%
+%% TODO: where/how to document classdef classes?
+%%
+%% @seealso{pyexec, pyeval}
+%% @end defun
+
+classdef pyobject < handle
+  properties
+    id
+  end
+
+  methods(Static)
+    function x = fromPythonVarName(pyvarname)
+      % if @var{pyvarname} is a string, its assumed to be a variable
+      % name, e.g., previously created with pyexec.  This must exist
+      % at the time of construction but it can disappear later (we
+      % will keep track of the reference).
+      if (~ ischar(pyvarname))
+        error('pyobject: currently we only take variable names as input')
+      end
+      cmd = sprintf ([ ...
+        'if not ("__InOct__" in vars() or "__InOct__" in globals()):\n' ...
+        '  __InOct__ = dict()\n' ...
+        '__InOct__[hex(id(%s))] = %s' ], ...
+        pyvarname, pyvarname);
+      pyexec (cmd);
+      id = pyeval (['hex(id(' pyvarname '))']);
+      x = pyobject(id);
+    end
+  end
+
+
+  methods
+    function x = pyobject(id)
+      % warning: not intended for casual use: you must also insert
+      % the object into the Python `__InOct__` dict with key `id`.
+      x.id = id;
+    end
+
+    function delete(x)
+      % called on clear of the last reference---for subclasses of
+      % handle; not called at all for "value classes".
+      % FIXME: #46497 this is never called!
+      %save('proof_of_delete', 6, x.id)
+      disp ('delete')
+      % throws KeyError if it wasn't in there for some reason
+      cmd = sprintf ('__InOct__.pop("%s")', x.id);
+      pyexec (cmd);
+    end
+
+    function force_delete (x)
+      % Manual workaround for #46497: call right before @code{clear x}.  But
+      % be careful, @code{x} needs to be the last reference: don't do this:
+      % @example
+      % d = pyobject (...);
+      % d2 = d;
+      % force_delete (d)
+      % clear d
+      % d2
+      %   @print{} ... KeyError ...
+      % @end example
+      delete(x)
+    end
+
+    dummy (x)
+
+    function r = getid (x)
+      r = x.id;
+    end
+
+    function disp(x)
+      printf ('[PyObject id %s]\n', x.id);
+      disp (pyeval (sprintf ('str(__InOct__["%s"])', x.id)))
+    end
+
+    function s = whatclass(x)
+      s = pyeval (sprintf ('str(__InOct__["%s"].__class__)', x.id));
+    end
+
+    function lst = whatmethods(x)
+      % filter the output of `dir(x)`
+      % properties only:
+      % [a for a in dir(x) if not callable(getattr(x, a)) and not a.startswith("__")]
+      cmd = sprintf ( ...
+        '[a for a in dir(__InOct__["%s"]) if not a.startswith("__")]', ...
+        x.id);
+      lst = pyeval (cmd);
+    end
+
+    function r = subsref(x, idx)
+      s = '';
+      for i=1:length(idx)
+        t = idx(i);
+        switch t.type
+          case '()'
+            if ( ! isempty (t.subs))
+              t
+              error('not implemented: function calls with arguments')
+            end
+            s = sprintf ('%s()', s);
+          case '.'
+            assert(ischar(t.subs))
+            s = sprintf ('%s.%s', s, t.subs);
+          otherwise
+            t
+            error('not implemented')
+        end
+      end
+      r = pyeval (sprintf ('__InOct__["%s"]%s', x.id, s));
+    end
+
+  end
+end