--- /dev/null
+## Copyright (C) 2005-2012 Søren Hauberg
+##
+## 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 {Command} {} doc @var{function_name}
+## Display documentation for the function @var{function_name}
+## directly from an on-line version of
+## the printed manual, using the GNU Info browser. If invoked without
+## any arguments, the manual is shown from the beginning.
+##
+## For example, the command @kbd{doc rand} starts the GNU Info browser
+## at the @code{rand} node in the on-line version of the manual.
+##
+## Once the GNU Info browser is running, help for using it is available
+## using the command @kbd{C-h}.
+## @seealso{help}
+## @end deftypefn
+
+## Author: Soren Hauberg <soren@hauberg.org>
+## Adapted-by: jwe
+
+function retval = doc (fname)
+
+ if (nargin == 0 || nargin == 1)
+
+ ftype = 0;
+
+ if (nargin == 1)
+ ## Get the directory where the function lives.
+ ## FIXME -- maybe we should have a better way of doing this.
+
+ if (ischar (fname))
+ ftype = exist (fname);
+ else
+ error ("doc: expecting argument to be a character string");
+ endif
+ else
+ fname = "";
+ endif
+
+ if (ftype == 2 || ftype == 3)
+ ffile = which (fname);
+ else
+ ffile = "";
+ endif
+
+ if (isempty (ffile))
+ info_dir = octave_config_info ("infodir");
+ else
+ info_dir = fileparts (ffile);
+ endif
+
+ ## Determine if a file called doc.info exist in the same
+ ## directory as the function.
+
+ info_file_name = fullfile (info_dir, "doc.info");
+
+ [stat_info, err] = stat (info_file_name);
+
+ if (err < 0)
+ info_file_name = info_file ();
+ endif
+
+ ## FIXME -- don't change the order of the arguments below because
+ ## the info-emacs-info script currently expects --directory DIR as
+ ## the third and fourth arguments. Someone should fix that.
+
+ cmd = sprintf ("\"%s\" --file \"%s\" --directory \"%s\"",
+ info_program (), info_file_name, info_dir);
+
+ have_fname = ! isempty (fname);
+
+ if (have_fname)
+ status = system (sprintf ("%s --index-search %s", cmd, fname));
+ endif
+
+ if (! (have_fname && status == 0))
+ status = system (cmd);
+ if (status == 127)
+ warning ("unable to find info program `%s'", info_program ());
+ endif
+ endif
+
+ if (nargout > 0)
+ retval = status;
+ endif
+
+ else
+ print_usage ();
+ endif
+
+endfunction
+
+%!test if exist( info_file ()) != 2 && exist (sprintf ("%s.gz", info_file ())) != 2
+%! error ("Info file %s or %s.gz does not exist!", info_file (), info_file ());
+%! endif