/*

Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 John W. Eaton
Copyright (C) 2009 VZLU Prague, a.s.
Copyright (C) 2010 Jaroslav Hajek

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/>.

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <iostream>
#include <sstream>
#include <vector>

#include "file-ops.h"
#include "oct-locbuf.h"

#include "defun.h"
#include "error.h"
#include "gripes.h"
#include "input.h"
#include "oct-map.h"
#include "ov-base.h"
#include "ov-fcn-handle.h"
#include "ov-usr-fcn.h"
#include "pr-output.h"
#include "pt-pr-code.h"
#include "pt-misc.h"
#include "pt-stmt.h"
#include "pt-cmd.h"
#include "pt-exp.h"
#include "pt-assign.h"
#include "pt-arg-list.h"
#include "variables.h"
#include "parse.h"
#include "unwind-prot.h"
#include "defaults.h"
#include "file-stat.h"
#include "load-path.h"
#include "oct-env.h"

#include "byte-swap.h"
#include "ls-ascii-helper.h"
#include "ls-hdf5.h"
#include "ls-oct-ascii.h"
#include "ls-oct-binary.h"
#include "ls-utils.h"

DEFINE_OCTAVE_ALLOCATOR (octave_fcn_handle);

DEFINE_OV_TYPEID_FUNCTIONS_AND_DATA (octave_fcn_handle,
                                     "function handle",
                                     "function_handle");

const std::string octave_fcn_handle::anonymous ("@<anonymous>");

octave_fcn_handle::octave_fcn_handle (const octave_value& f,
                                      const std::string& n)
  : fcn (f), nm (n), has_overloads (false)
{
  octave_user_function *uf = fcn.user_function_value (true);

  if (uf && nm != anonymous)
    symbol_table::cache_name (uf->scope (), nm);
}

octave_value_list
octave_fcn_handle::subsref (const std::string& type,
                            const std::list<octave_value_list>& idx,
                            int nargout)
{
  return octave_fcn_handle::subsref (type, idx, nargout, 0);
}

octave_value_list
octave_fcn_handle::subsref (const std::string& type,
                            const std::list<octave_value_list>& idx,
                            int nargout, const std::list<octave_lvalue>* lvalue_list)
{
  octave_value_list retval;

  switch (type[0])
    {
    case '(':
      {
        int tmp_nargout = (type.length () > 1 && nargout == 0) ? 1 : nargout;

        retval = do_multi_index_op (tmp_nargout, idx.front (),
                                    idx.size () == 1 ? lvalue_list : 0);
      }
      break;

    case '{':
    case '.':
      {
        std::string tnm = type_name ();
        error ("%s cannot be indexed with %c", tnm.c_str (), type[0]);
      }
      break;

    default:
      panic_impossible ();
    }

  // FIXME -- perhaps there should be an
  // octave_value_list::next_subsref member function?  See also
  // octave_builtin::subsref.

  if (idx.size () > 1)
    retval = retval(0).next_subsref (nargout, type, idx);

  return retval;
}

octave_value_list
octave_fcn_handle::do_multi_index_op (int nargout, 
                                      const octave_value_list& args)
{
  return do_multi_index_op (nargout, args, 0);
}

octave_value_list
octave_fcn_handle::do_multi_index_op (int nargout, 
                                      const octave_value_list& args,
                                      const std::list<octave_lvalue>* lvalue_list)
{
  octave_value_list retval;

  out_of_date_check (fcn, std::string (), false);

  if (has_overloads)
    {
      // Possibly overloaded function.
      octave_value ov_fcn;

      // Compute dispatch type.
      builtin_type_t btyp;
      std::string dispatch_type = get_dispatch_type (args, btyp);

      // Retrieve overload.
      if (btyp != btyp_unknown)
        {
          out_of_date_check (builtin_overloads[btyp], dispatch_type, false);
          ov_fcn = builtin_overloads[btyp];
        }
      else
        {
          str_ov_map::iterator it = overloads.find (dispatch_type);
          if (it != overloads.end ())
            {
              out_of_date_check (it->second, dispatch_type, false);
              ov_fcn = it->second;
            }
        }

      if (ov_fcn.is_defined ())
        retval = ov_fcn.do_multi_index_op (nargout, args, lvalue_list);
      else if (fcn.is_defined ())
        retval = fcn.do_multi_index_op (nargout, args, lvalue_list);
      else
        error ("%s: no method for class %s", nm.c_str (), dispatch_type.c_str ());
    }
  else
    {
      // Non-overloaded function (anonymous, subfunction, private function).
      if (fcn.is_defined ())
        retval = fcn.do_multi_index_op (nargout, args, lvalue_list);
      else
        error ("%s: no longer valid function handle", nm.c_str ());
    }

  return retval;
}

bool 
octave_fcn_handle::is_equal_to (const octave_fcn_handle& h) const
{
  bool retval = fcn.is_copy_of (h.fcn) && (has_overloads == h.has_overloads);
  retval = retval && (overloads.size () == h.overloads.size ());

  if (retval && has_overloads)
    {
      for (int i = 0; i < btyp_num_types && retval; i++)
        retval = builtin_overloads[i].is_copy_of (h.builtin_overloads[i]);

      str_ov_map::const_iterator iter = overloads.begin (), hiter = h.overloads.begin ();
      for (; iter != overloads.end () && retval; iter++, hiter++)
        retval = (iter->first == hiter->first) && (iter->second.is_copy_of (hiter->second));
    }

  return retval;
}

bool
octave_fcn_handle::set_fcn (const std::string &octaveroot, 
                            const std::string& fpath)
{
  bool success = true;

  if (octaveroot.length () != 0
      && fpath.length () >= octaveroot.length ()
      && fpath.substr (0, octaveroot.length ()) == octaveroot
      && OCTAVE_EXEC_PREFIX != octaveroot)
    {
      // First check if just replacing matlabroot is enough
      std::string str = OCTAVE_EXEC_PREFIX + 
        fpath.substr (octaveroot.length ());                
      file_stat fs (str);

      if (fs.exists ())
        {
          size_t xpos = str.find_last_of (file_ops::dir_sep_chars ());

          std::string dir_name = str.substr (0, xpos);

          octave_function *xfcn
            = load_fcn_from_file (str, dir_name, "", nm);

          if (xfcn)
            {
              octave_value tmp (xfcn);

              fcn = octave_value (new octave_fcn_handle (tmp, nm));
            }
          else
            {
              error ("function handle points to non-existent function");
              success = false;
            }
        }
      else
        {
          // Next just search for it anywhere in the system path
          string_vector names(3);
          names(0) = nm + ".oct";
          names(1) = nm + ".mex";
          names(2) = nm + ".m";

          dir_path p (load_path::system_path ());

          str = octave_env::make_absolute (p.find_first_of (names));

          size_t xpos = str.find_last_of (file_ops::dir_sep_chars ());

          std::string dir_name = str.substr (0, xpos);

          octave_function *xfcn = load_fcn_from_file (str, dir_name, "", nm);

          if (xfcn)
            {
              octave_value tmp (xfcn);

              fcn = octave_value (new octave_fcn_handle (tmp, nm));
            }
          else
            {
              error ("function handle points to non-existent function");
              success = false;
            }
        }
    }
  else
    {
      if (fpath.length () > 0)
        {
          size_t xpos = fpath.find_last_of (file_ops::dir_sep_chars ());

          std::string dir_name = fpath.substr (0, xpos);

          octave_function *xfcn = load_fcn_from_file (fpath, dir_name, "", nm);

          if (xfcn)
            {
              octave_value tmp (xfcn);

              fcn = octave_value (new octave_fcn_handle (tmp, nm));
            }
          else
            {
              error ("function handle points to non-existent function");
              success = false;
            }
        }
      else
        {
          fcn = symbol_table::find_function (nm);

          if (! fcn.is_function ())
            {
              error ("function handle points to non-existent function");
              success = false;
            }
        }
    }

  return success;
}

bool
octave_fcn_handle::save_ascii (std::ostream& os)
{
  if (nm == anonymous)
    {
      os << nm << "\n";

      print_raw (os, true);
      os << "\n";

      if (fcn.is_undefined ())
        return false;

      octave_user_function *f = fcn.user_function_value ();

      std::list<symbol_table::symbol_record> vars
        = symbol_table::all_variables (f->scope (), 0);

      size_t varlen = vars.size ();

      if (varlen > 0)
        {
          os << "# length: " << varlen << "\n";

          for (std::list<symbol_table::symbol_record>::const_iterator p = vars.begin ();
               p != vars.end (); p++)
            {
              if (! save_ascii_data (os, p->varval (), p->name (), false, 0))
                return os;
            }
        }
    }
  else
    {
      octave_function *f = function_value ();
      std::string fnm = f ? f->fcn_file_name () : std::string ();

      os << "# octaveroot: " << OCTAVE_EXEC_PREFIX << "\n";
      if (! fnm.empty ())
        os << "# path: " << fnm << "\n";
      os << nm << "\n";
    }

  return true;
}

bool
octave_fcn_handle::load_ascii (std::istream& is)
{
  bool success = true;

  std::streampos pos = is.tellg ();
  std::string octaveroot = extract_keyword (is, "octaveroot", true);
  if (octaveroot.length() == 0)
    {
      is.seekg (pos);
      is.clear ();
    }
  pos = is.tellg ();
  std::string fpath = extract_keyword (is, "path", true);
  if (fpath.length() == 0)
    {
      is.seekg (pos);
      is.clear ();
    }

  is >> nm;

  if (nm == anonymous)
    {
      skip_preceeding_newline (is);

      std::string buf;

      if (is)
        {

          // Get a line of text whitespace characters included, leaving
          // newline in the stream.
          buf = read_until_newline (is, true);

        }

      pos = is.tellg ();

      unwind_protect_safe frame;

      // Set up temporary scope to use for evaluating the text that
      // defines the anonymous function.

      symbol_table::scope_id local_scope = symbol_table::alloc_scope ();
      frame.add_fcn (symbol_table::erase_scope, local_scope);

      symbol_table::set_scope (local_scope);

      octave_call_stack::push (local_scope, 0);
      frame.add_fcn (octave_call_stack::pop);

      octave_idx_type len = 0;

      if (extract_keyword (is, "length", len, true) && len >= 0)
        {
          if (len > 0)
            {
              for (octave_idx_type i = 0; i < len; i++)
                {
                  octave_value t2;
                  bool dummy;

                  std::string name
                    = read_ascii_data (is, std::string (), dummy, t2, i);

                  if (!is)
                    {
                      error ("load: failed to load anonymous function handle");
                      break;
                    }

                  symbol_table::varref (name, local_scope, 0) = t2;
                }
            }
        }
      else
        {
          is.seekg (pos);
          is.clear ();
        }

      if (is && success)
        {
          int parse_status;
          octave_value anon_fcn_handle = 
            eval_string (buf, true, parse_status);

          if (parse_status == 0)
            {
              octave_fcn_handle *fh = 
                anon_fcn_handle.fcn_handle_value ();

              if (fh)
                {
                  fcn = fh->fcn;

                  octave_user_function *uf = fcn.user_function_value (true);

                  if (uf)
                    symbol_table::cache_name (uf->scope (), nm);
                }
              else
                success = false;
            }
          else
            success = false;
        }
      else
        success = false;
    }
  else
    success = set_fcn (octaveroot, fpath);

  return success;
}

bool
octave_fcn_handle::save_binary (std::ostream& os, bool& save_as_floats)
{
  if (nm == anonymous)
    {
      std::ostringstream nmbuf;

      if (fcn.is_undefined ())
        return false;

      octave_user_function *f = fcn.user_function_value ();

      std::list<symbol_table::symbol_record> vars
        = symbol_table::all_variables (f->scope (), 0);

      size_t varlen = vars.size ();

      if (varlen > 0)
        nmbuf << nm << " " << varlen;
      else
        nmbuf << nm;

      std::string buf_str = nmbuf.str();
      int32_t tmp = buf_str.length ();
      os.write (reinterpret_cast<char *> (&tmp), 4);
      os.write (buf_str.c_str (), buf_str.length ());

      std::ostringstream buf;
      print_raw (buf, true);
      std::string stmp = buf.str ();
      tmp = stmp.length ();
      os.write (reinterpret_cast<char *> (&tmp), 4);
      os.write (stmp.c_str (), stmp.length ());

      if (varlen > 0)
        {
          for (std::list<symbol_table::symbol_record>::const_iterator p = vars.begin ();
               p != vars.end (); p++)
            {
              if (! save_binary_data (os, p->varval (), p->name (),
                                      "", 0, save_as_floats))
                return os;
            }
        }
    }
  else
    {
      std::ostringstream nmbuf;

      octave_function *f = function_value ();
      std::string fnm = f ? f->fcn_file_name () : std::string ();

      nmbuf << nm << "\n" << OCTAVE_EXEC_PREFIX << "\n" << fnm;

      std::string buf_str = nmbuf.str ();
      int32_t tmp = buf_str.length ();
      os.write (reinterpret_cast<char *> (&tmp), 4);
      os.write (buf_str.c_str (), buf_str.length ());
    }

  return true;
}

bool
octave_fcn_handle::load_binary (std::istream& is, bool swap,
                                oct_mach_info::float_format fmt)
{
  bool success = true;

  int32_t tmp;
  if (! is.read (reinterpret_cast<char *> (&tmp), 4))
    return false;
  if (swap)
    swap_bytes<4> (&tmp);

  OCTAVE_LOCAL_BUFFER (char, ctmp1, tmp+1);
  is.get (ctmp1, tmp+1, 0);
  nm = std::string (ctmp1);

  if (! is)
    return false;

  size_t anl = anonymous.length ();

  if (nm.length() >= anl && nm.substr (0, anl) == anonymous)
    {
      octave_idx_type len = 0;

      if (nm.length() > anl)
        {
          std::istringstream nm_is (nm.substr (anl));
          nm_is >> len;
          nm = nm.substr (0, anl);
        }

      if (! is.read (reinterpret_cast<char *> (&tmp), 4))
        return false;
      if (swap)
        swap_bytes<4> (&tmp);

      OCTAVE_LOCAL_BUFFER (char, ctmp2, tmp+1);
      is.get (ctmp2, tmp+1, 0);

      unwind_protect_safe frame;

      // Set up temporary scope to use for evaluating the text that
      // defines the anonymous function.

      symbol_table::scope_id local_scope = symbol_table::alloc_scope ();
      frame.add_fcn (symbol_table::erase_scope, local_scope);         

      symbol_table::set_scope (local_scope);

      octave_call_stack::push (local_scope, 0);
      frame.add_fcn (octave_call_stack::pop);

      if (len > 0)
        {
          for (octave_idx_type i = 0; i < len; i++)
            {
              octave_value t2;
              bool dummy;
              std::string doc;

              std::string name = 
                read_binary_data (is, swap, fmt, std::string (), 
                                  dummy, t2, doc);

              if (!is)
                {
                  error ("load: failed to load anonymous function handle");
                  break;
                }

              symbol_table::varref (name, local_scope) = t2;
            }
        }

      if (is && success)
        {
          int parse_status;
          octave_value anon_fcn_handle = 
            eval_string (ctmp2, true, parse_status);

          if (parse_status == 0)
            {
              octave_fcn_handle *fh = anon_fcn_handle.fcn_handle_value ();

              if (fh)
                {
                  fcn = fh->fcn;

                  octave_user_function *uf = fcn.user_function_value (true);

                  if (uf)
                    symbol_table::cache_name (uf->scope (), nm);
                }
              else
                success = false;
            }
          else
            success = false;
        }
    }
  else
    {
      std::string octaveroot;
      std::string fpath;

      if (nm.find_first_of ("\n") != std::string::npos)
        {
          size_t pos1 = nm.find_first_of ("\n");
          size_t pos2 = nm.find_first_of ("\n", pos1 + 1);
          octaveroot = nm.substr (pos1 + 1, pos2 - pos1 - 1);
          fpath = nm.substr (pos2 + 1);
          nm = nm.substr (0, pos1);
        }

      success = set_fcn (octaveroot, fpath);
     }
 
 return success;
}

#if defined (HAVE_HDF5)
bool
octave_fcn_handle::save_hdf5 (hid_t loc_id, const char *name,
                              bool save_as_floats)
{
  bool retval = true;

  hid_t group_hid = -1;
#if HAVE_HDF5_18
  group_hid = H5Gcreate (loc_id, name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
#else
  group_hid = H5Gcreate (loc_id, name, 0);
#endif
  if (group_hid < 0)
    return false;

  hid_t space_hid = -1, data_hid = -1, type_hid = -1;;

  // attach the type of the variable
  type_hid = H5Tcopy (H5T_C_S1);
  H5Tset_size (type_hid, nm.length () + 1);
  if (type_hid < 0)
    {
      H5Gclose (group_hid);
      return false;
    }

  OCTAVE_LOCAL_BUFFER (hsize_t, hdims, 2);
  hdims[0] = 0;
  hdims[1] = 0;
  space_hid = H5Screate_simple (0 , hdims, 0);
  if (space_hid < 0)
    {
      H5Tclose (type_hid);
      H5Gclose (group_hid);
      return false;
    }
#if HAVE_HDF5_18
  data_hid = H5Dcreate (group_hid, "nm",  type_hid, space_hid, 
                        H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
#else
  data_hid = H5Dcreate (group_hid, "nm",  type_hid, space_hid, H5P_DEFAULT);
#endif
  if (data_hid < 0 || H5Dwrite (data_hid, type_hid, H5S_ALL, H5S_ALL,
                                H5P_DEFAULT, nm.c_str ()) < 0)
    {
      H5Sclose (space_hid);
      H5Tclose (type_hid);
      H5Gclose (group_hid);
      return false;
    }
  H5Dclose (data_hid);

  if (nm == anonymous)
    {
      std::ostringstream buf;
      print_raw (buf, true);
      std::string stmp = buf.str ();

      // attach the type of the variable
      H5Tset_size (type_hid, stmp.length () + 1);
      if (type_hid < 0)
        {
          H5Sclose (space_hid);
          H5Gclose (group_hid);
          return false;
        }

#if HAVE_HDF5_18
      data_hid = H5Dcreate (group_hid, "fcn",  type_hid, space_hid,
                            H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
#else
      data_hid = H5Dcreate (group_hid, "fcn",  type_hid, space_hid,
                            H5P_DEFAULT);
#endif
      if (data_hid < 0 || H5Dwrite (data_hid, type_hid, H5S_ALL, H5S_ALL,
                                    H5P_DEFAULT, stmp.c_str ()) < 0)
        {
          H5Sclose (space_hid);
          H5Tclose (type_hid);
          H5Gclose (group_hid);
          return false;
        }

      H5Dclose (data_hid);

      octave_user_function *f = fcn.user_function_value ();

      std::list<symbol_table::symbol_record> vars
        = symbol_table::all_variables (f->scope (), 0);

      size_t varlen = vars.size ();

      if (varlen > 0)
        {
          hid_t as_id = H5Screate (H5S_SCALAR);

          if (as_id >= 0)
            {
#if HAVE_HDF5_18
              hid_t a_id = H5Acreate (group_hid, "SYMBOL_TABLE",
                                      H5T_NATIVE_IDX, as_id, 
                                      H5P_DEFAULT, H5P_DEFAULT);

#else
              hid_t a_id = H5Acreate (group_hid, "SYMBOL_TABLE",
                                      H5T_NATIVE_IDX, as_id, H5P_DEFAULT);
#endif

              if (a_id >= 0)
                {
                  retval = (H5Awrite (a_id, H5T_NATIVE_IDX, &varlen) >= 0);

                  H5Aclose (a_id);
                }
              else
                retval = false;

              H5Sclose (as_id);
            }
          else
            retval = false;
#if HAVE_HDF5_18
          data_hid = H5Gcreate (group_hid, "symbol table", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
#else
          data_hid = H5Gcreate (group_hid, "symbol table", 0);
#endif
          if (data_hid < 0) 
            {
              H5Sclose (space_hid);
              H5Tclose (type_hid);
              H5Gclose (group_hid);
              return false;
            }

          for (std::list<symbol_table::symbol_record>::const_iterator p = vars.begin ();
               p != vars.end (); p++)
            {
              if (! add_hdf5_data (data_hid, p->varval (), p->name (),
                                   "", false, save_as_floats))
                break;
            }
          H5Gclose (data_hid);
        }
    }
  else
    {
      std::string octaveroot = OCTAVE_EXEC_PREFIX;

      octave_function *f = function_value ();
      std::string fpath = f ? f->fcn_file_name () : std::string ();

      H5Sclose (space_hid);
      hdims[0] = 1;
      hdims[1] = octaveroot.length ();
      space_hid = H5Screate_simple (0 , hdims, 0);
      if (space_hid < 0)
        {
          H5Tclose (type_hid);
          H5Gclose (group_hid);
          return false;
        }

      H5Tclose (type_hid);
      type_hid = H5Tcopy (H5T_C_S1);
      H5Tset_size (type_hid, octaveroot.length () + 1);
#if HAVE_HDF5_18
      hid_t a_id = H5Acreate (group_hid, "OCTAVEROOT",
                              type_hid, space_hid, H5P_DEFAULT, H5P_DEFAULT);
#else
      hid_t a_id = H5Acreate (group_hid, "OCTAVEROOT",
                              type_hid, space_hid, H5P_DEFAULT);
#endif

      if (a_id >= 0)
        {
          retval = (H5Awrite (a_id, type_hid, octaveroot.c_str ()) >= 0);

          H5Aclose (a_id);
        }
      else
        {
          H5Sclose (space_hid);
          H5Tclose (type_hid);
          H5Gclose (group_hid);
          return false;
        }

      H5Sclose (space_hid);
      hdims[0] = 1;
      hdims[1] = fpath.length ();
      space_hid = H5Screate_simple (0 , hdims, 0);
      if (space_hid < 0)
        {
          H5Tclose (type_hid);
          H5Gclose (group_hid);
          return false;
        }

      H5Tclose (type_hid);
      type_hid = H5Tcopy (H5T_C_S1);
      H5Tset_size (type_hid, fpath.length () + 1);

#if HAVE_HDF5_18
      a_id = H5Acreate (group_hid, "FILE", type_hid, space_hid, 
                        H5P_DEFAULT, H5P_DEFAULT);
#else
      a_id = H5Acreate (group_hid, "FILE", type_hid, space_hid, H5P_DEFAULT);
#endif

      if (a_id >= 0)
        {
          retval = (H5Awrite (a_id, type_hid, fpath.c_str ()) >= 0);

          H5Aclose (a_id);
        }
      else
        retval = false;
    }

  H5Sclose (space_hid);
  H5Tclose (type_hid);
  H5Gclose (group_hid);

  return retval;
}

bool
octave_fcn_handle::load_hdf5 (hid_t loc_id, const char *name)
{
  bool success = true;

  hid_t group_hid, data_hid, space_hid, type_hid, type_class_hid, st_id;
  hsize_t rank;
  int slen;

#if HAVE_HDF5_18
  group_hid = H5Gopen (loc_id, name, H5P_DEFAULT);
#else
  group_hid = H5Gopen (loc_id, name);
#endif
  if (group_hid < 0)
    return false;

#if HAVE_HDF5_18
  data_hid = H5Dopen (group_hid, "nm", H5P_DEFAULT);
#else
  data_hid = H5Dopen (group_hid, "nm");
#endif

  if (data_hid < 0)
    {
      H5Gclose (group_hid);
      return false;
    }

  type_hid = H5Dget_type (data_hid);
  type_class_hid = H5Tget_class (type_hid);

  if (type_class_hid != H5T_STRING)
    {
      H5Tclose (type_hid);
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }

  space_hid = H5Dget_space (data_hid);
  rank = H5Sget_simple_extent_ndims (space_hid);

  if (rank != 0)
    {
      H5Sclose (space_hid);
      H5Tclose (type_hid);
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }

  slen = H5Tget_size (type_hid);
  if (slen < 0)
    {
      H5Sclose (space_hid);
      H5Tclose (type_hid);
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }

  OCTAVE_LOCAL_BUFFER (char, nm_tmp, slen);

  // create datatype for (null-terminated) string to read into:
  st_id = H5Tcopy (H5T_C_S1);
  H5Tset_size (st_id, slen);

  if (H5Dread (data_hid, st_id, H5S_ALL, H5S_ALL, H5P_DEFAULT, nm_tmp) < 0)
    {
      H5Tclose (st_id);
      H5Sclose (space_hid);
      H5Tclose (type_hid);
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
  H5Tclose (st_id);
  H5Dclose (data_hid);
  nm = nm_tmp;

  if (nm == anonymous)
    {
#if HAVE_HDF5_18
      data_hid = H5Dopen (group_hid, "fcn", H5P_DEFAULT);
#else
      data_hid = H5Dopen (group_hid, "fcn");
#endif

      if (data_hid < 0)
        {
          H5Sclose (space_hid);
          H5Tclose (type_hid);
          H5Gclose (group_hid);
          return false;
        }

      H5Tclose (type_hid);
      type_hid = H5Dget_type (data_hid);
      type_class_hid = H5Tget_class (type_hid);

      if (type_class_hid != H5T_STRING)
        {
          H5Sclose (space_hid);
          H5Tclose (type_hid);
          H5Dclose (data_hid);
          H5Gclose (group_hid);
          return false;
        }

      H5Sclose (space_hid);
      space_hid = H5Dget_space (data_hid);
      rank = H5Sget_simple_extent_ndims (space_hid);

      if (rank != 0)
        {
          H5Sclose (space_hid);
          H5Tclose (type_hid);
          H5Dclose (data_hid);
          H5Gclose (group_hid);
          return false;
        }

      slen = H5Tget_size (type_hid);
      if (slen < 0)
        {
          H5Sclose (space_hid);
          H5Tclose (type_hid);
          H5Dclose (data_hid);
          H5Gclose (group_hid);
          return false;
        }

      OCTAVE_LOCAL_BUFFER (char, fcn_tmp, slen);

      // create datatype for (null-terminated) string to read into:
      st_id = H5Tcopy (H5T_C_S1);
      H5Tset_size (st_id, slen);

      if (H5Dread (data_hid, st_id, H5S_ALL, H5S_ALL, H5P_DEFAULT, fcn_tmp) < 0)
        {
          H5Tclose (st_id);
          H5Sclose (space_hid);
          H5Tclose (type_hid);
          H5Dclose (data_hid);
          H5Gclose (group_hid);
          return false;
        }
      H5Tclose (st_id);
      H5Dclose (data_hid);

      octave_idx_type len = 0;

      // we have to pull some shenanigans here to make sure
      // HDF5 doesn't print out all sorts of error messages if we
      // call H5Aopen for a non-existing attribute

      H5E_auto_t err_func;
      void *err_func_data;

      // turn off error reporting temporarily, but save the error
      // reporting function:
#if HAVE_HDF5_18
      H5Eget_auto (H5E_DEFAULT, &err_func, &err_func_data);
      H5Eset_auto (H5E_DEFAULT, 0, 0);
#else
      H5Eget_auto (&err_func, &err_func_data);
      H5Eset_auto (0, 0);
#endif

      hid_t attr_id = H5Aopen_name (group_hid, "SYMBOL_TABLE");

      if (attr_id >= 0)
        {
          if (H5Aread (attr_id, H5T_NATIVE_IDX, &len) < 0)
            success = false;

          H5Aclose (attr_id);
        }

      // restore error reporting:
#if HAVE_HDF5_18
      H5Eset_auto (H5E_DEFAULT, err_func, err_func_data);
#else
      H5Eset_auto (err_func, err_func_data);
#endif

      unwind_protect_safe frame;

      // Set up temporary scope to use for evaluating the text that
      // defines the anonymous function.

      symbol_table::scope_id local_scope = symbol_table::alloc_scope ();
      frame.add_fcn (symbol_table::erase_scope, local_scope);

      symbol_table::set_scope (local_scope);

      octave_call_stack::push (local_scope, 0);
      frame.add_fcn (octave_call_stack::pop);

      if (len > 0 && success)
        {
          hsize_t num_obj = 0;
#if HAVE_HDF5_18
          data_hid = H5Gopen (group_hid, "symbol table", H5P_DEFAULT); 
#else
          data_hid = H5Gopen (group_hid, "symbol table"); 
#endif
          H5Gget_num_objs (data_hid, &num_obj);
          H5Gclose (data_hid);

          if (num_obj != static_cast<hsize_t>(len))
            {
              error ("load: failed to load anonymous function handle");
              success = false;
            }

          if (! error_state)
            {
              hdf5_callback_data dsub;
              int current_item = 0;
              for (octave_idx_type i = 0; i < len; i++)
                {
                  if (H5Giterate (group_hid, "symbol table", &current_item,
                                  hdf5_read_next_data, &dsub) <= 0)
                    {
                      error ("load: failed to load anonymous function handle");
                      success = false;
                      break;
                    }

                  symbol_table::varref (dsub.name, local_scope) = dsub.tc;
                }
            }
        }

      if (success)
        {
          int parse_status;
          octave_value anon_fcn_handle = 
            eval_string (fcn_tmp, true, parse_status);

          if (parse_status == 0)
            {
              octave_fcn_handle *fh = anon_fcn_handle.fcn_handle_value ();

              if (fh)
                {
                  fcn = fh->fcn;

                  octave_user_function *uf = fcn.user_function_value (true);

                  if (uf)
                    symbol_table::cache_name (uf->scope (), nm);
                }
              else
                success = false;
            }
          else
            success = false;
        }

      frame.run ();
    }
  else
    {
      std::string octaveroot;
      std::string fpath;

      // we have to pull some shenanigans here to make sure
      // HDF5 doesn't print out all sorts of error messages if we
      // call H5Aopen for a non-existing attribute

      H5E_auto_t err_func;
      void *err_func_data;

      // turn off error reporting temporarily, but save the error
      // reporting function:
#if HAVE_HDF5_18
      H5Eget_auto (H5E_DEFAULT, &err_func, &err_func_data);
      H5Eset_auto (H5E_DEFAULT, 0, 0);
#else
      H5Eget_auto (&err_func, &err_func_data);
      H5Eset_auto (0, 0);
#endif

      hid_t attr_id = H5Aopen_name (group_hid, "OCTAVEROOT");
      if (attr_id >= 0)
        {
          H5Tclose (type_hid);
          type_hid = H5Aget_type (attr_id);
          type_class_hid = H5Tget_class (type_hid);

          if (type_class_hid != H5T_STRING)
            success = false;
          else
            {
              slen = H5Tget_size (type_hid);
              st_id = H5Tcopy (H5T_C_S1);
              H5Tset_size (st_id, slen);
              OCTAVE_LOCAL_BUFFER (char, root_tmp, slen);

              if (H5Aread (attr_id, st_id, root_tmp) < 0)
                success = false;
              else
                octaveroot = root_tmp;

              H5Tclose (st_id);
            }

          H5Aclose (attr_id);
        }

      if (success)
        {
          attr_id = H5Aopen_name (group_hid, "FILE");
          if (attr_id >= 0)
            {
              H5Tclose (type_hid);
              type_hid = H5Aget_type (attr_id);
              type_class_hid = H5Tget_class (type_hid);

              if (type_class_hid != H5T_STRING)
                success = false;
              else
                {
                  slen = H5Tget_size (type_hid);
                  st_id = H5Tcopy (H5T_C_S1);
                  H5Tset_size (st_id, slen);
                  OCTAVE_LOCAL_BUFFER (char, path_tmp, slen);

                  if (H5Aread (attr_id, st_id, path_tmp) < 0)
                    success = false;
                  else
                    fpath = path_tmp;

                  H5Tclose (st_id);
                }

              H5Aclose (attr_id);
            }
        }

      // restore error reporting:
#if HAVE_HDF5_18
      H5Eset_auto (H5E_DEFAULT, err_func, err_func_data);
#else
      H5Eset_auto (err_func, err_func_data);
#endif

      success = (success ? set_fcn (octaveroot, fpath) : success);
    }

  H5Tclose (type_hid);
  H5Sclose (space_hid);
  H5Gclose (group_hid);

  return success;
}

#endif

/* 

%!test
%! a = 2;
%! f = @(x) a + x;
%! g = @(x) 2 * x;
%! hm = @flops;
%! hdld = @svd;
%! hbi = @log2;
%! f2 = f;
%! g2 = g;
%! hm2 = hm;
%! hdld2 = hdld;
%! hbi2 = hbi;
%! modes = {"-text", "-binary"};
%! if (!isempty(findstr(octave_config_info ("DEFS"),"HAVE_HDF5")))
%!   modes(end+1) = "-hdf5";
%! endif
%! for i = 1:numel (modes)
%!   mode = modes{i};
%!   nm = tmpnam();
%!   unwind_protect
%!     save (mode, nm, "f2", "g2", "hm2", "hdld2", "hbi2");
%!     clear f2 g2 hm2 hdld2 hbi2
%!     load (nm);
%!     assert (f(2),f2(2));
%!     assert (g(2),g2(2));
%!     assert (g(3),g2(3));
%!     unlink (nm);
%!     save (mode, nm, "f2", "g2", "hm2", "hdld2", "hbi2");
%!   unwind_protect_cleanup
%!     unlink (nm);
%!   end_unwind_protect
%! endfor

*/

void
octave_fcn_handle::print (std::ostream& os, bool pr_as_read_syntax) const
{
  print_raw (os, pr_as_read_syntax);
  newline (os);
}

void
octave_fcn_handle::print_raw (std::ostream& os, bool pr_as_read_syntax) const
{
  bool printed = false;

  if (nm == anonymous)
    {
      tree_print_code tpc (os);

      // FCN is const because this member function is, so we can't
      // use it to call user_function_value, so we make a copy first.

      octave_value ftmp = fcn;

      octave_user_function *f = ftmp.user_function_value ();

      if (f)
        {
          tree_parameter_list *p = f->parameter_list ();

          os << "@(";

          if (p)
            p->accept (tpc);

          os << ") ";

          tree_statement_list *b = f->body ();

          if (b)
            {
              assert (b->length () == 1);

              tree_statement *s = b->front ();

              if (s)
                {
                  if (s->is_expression ())
                    {
                      tree_expression *e = s->expression ();

                      if (e)
                        e->accept (tpc);
                    }
                  else
                    {
                      tree_command *c = s->command ();

                      tpc.suspend_newline ();
                      c->accept (tpc);
                      tpc.resume_newline ();
                    }
                }
            }

          printed = true;
        }
    }

  if (! printed)
    octave_print_internal (os, "@" + nm, pr_as_read_syntax,
                           current_print_indent_level ());
}

octave_value
make_fcn_handle (const std::string& nm, bool local_funcs)
{
  octave_value retval;

  // Bow to the god of compatibility.

  // FIXME -- it seems ugly to put this here, but there is no single
  // function in the parser that converts from the operator name to
  // the corresponding function name.  At least try to do it without N
  // string compares.

  std::string tnm = nm;

  size_t len = nm.length ();

  if (len == 3 && nm == ".**")
    tnm = "power";
  else if (len == 2)
    {
      if (nm[0] == '.')
        {
          switch (nm[1])
            {
            case '\'':
              tnm = "transpose";
              break;

            case '+':
              tnm = "plus";
              break;

            case '-':
              tnm = "minus";
              break;

            case '*':
              tnm = "times";
              break;

            case '/':
              tnm = "rdivide";
              break;

            case '^':
              tnm = "power";
              break;

            case '\\':
              tnm = "ldivide";
              break;
            }
        }
      else if (nm[1] == '=')
        {
          switch (nm[0])
            {
            case '<':
              tnm = "le";
              break;

            case '=':
              tnm = "eq";
              break;

            case '>':
              tnm = "ge";
              break;

            case '~':
            case '!':
              tnm = "ne";
              break;
            }
        }
      else if (nm == "**")
        tnm = "mpower";
    }
  else if (len == 1)
    {
      switch (nm[0])
        {
        case '~':
        case '!':
          tnm = "not";
          break;

        case '\'':
          tnm = "ctranspose";
          break;

        case '+':
          tnm = "plus";
          break;

        case '-':
          tnm = "minus";
          break;

        case '*':
          tnm = "mtimes";
          break;

        case '/':
          tnm = "mrdivide";
          break;

        case '^':
          tnm = "mpower";
          break;

        case '\\':
          tnm = "mldivide";
          break;

        case '<':
          tnm = "lt";
          break;

        case '>':
          tnm = "gt";
          break;

        case '&':
          tnm = "and";
          break;

        case '|':
          tnm = "or";
          break;
        }
    }

  octave_value f = symbol_table::find_function (tnm, octave_value_list (),
                                                local_funcs);
  octave_function *fptr = f.function_value (true);

  if (local_funcs && fptr 
      && (fptr->is_nested_function () || fptr->is_private_function ()
          || fptr->is_class_constructor ()))
    {
      // Locally visible function.
      retval = octave_value (new octave_fcn_handle (f, tnm));
    }
  else
    {
      // Globally visible (or no match yet). Query overloads.
      std::list<std::string> classes = load_path::overloads (tnm);
      bool any_match = fptr != 0 || classes.size () > 0;
      if (! any_match)
        {
          // No match found, try updating load_path and query classes again.
          load_path::update ();
          classes = load_path::overloads (tnm);
          any_match = classes.size () > 0;
        }

      if (any_match)
        {
          octave_fcn_handle *fh = new octave_fcn_handle (f, tnm);
          retval = fh;

          for (std::list<std::string>::iterator iter = classes.begin ();
               iter != classes.end (); iter++)
            {
              std::string class_name = *iter;
              octave_value fmeth = symbol_table::find_method (tnm, class_name);

              bool is_builtin = false;
              for (int i = 0; i < btyp_num_types; i++)
                {
                  // FIXME: Too slow? Maybe binary lookup?
                  if (class_name == btyp_class_name[i])
                    {
                      is_builtin = true;
                      fh->set_overload (static_cast<builtin_type_t> (i), fmeth);
                    }
                }

              if (! is_builtin)
                fh->set_overload (class_name, fmeth);
            }
        }
      else
        error ("@%s: no function and no method found", tnm.c_str ());
    }

  return retval;
}

/*
%!test
%! x = {".**", "power";
%!      ".'", "transpose";
%!      ".+", "plus";
%!      ".-", "minus";
%!      ".*", "times";
%!      "./", "rdivide";
%!      ".^", "power";
%!      ".\\", "ldivide";
%!      "<=", "le";
%!      "==", "eq";
%!      ">=", "ge";
%!      "~=", "ne";
%!      "!=", "ne";
%!      "**", "mpower";
%!      "~", "not";
%!      "!", "not";
%!      "\'", "ctranspose";
%!      "+", "plus";
%!      "-", "minus";
%!      "*", "mtimes";
%!      "/", "mrdivide";
%!      "^", "mpower";
%!      "\\", "mldivide";
%!      "<", "lt";
%!      ">", "gt";
%!      "&", "and";
%!      "|", "or"};
%! for i = 1:rows (x)
%!   assert (functions (str2func (x{i,1})).function, x{i,2})
%! endfor
*/

DEFUN (functions, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} functions (@var{fcn_handle})\n\
Return a struct containing information about the function handle\n\
@var{fcn_handle}.\n\
@end deftypefn")
{
  octave_value retval;

  if (args.length () == 1)
    {
      octave_fcn_handle *fh = args(0).fcn_handle_value ();

      if (! error_state)
        {
          octave_function *fcn = fh ? fh->function_value () : 0;

          if (fcn)
            {
              octave_scalar_map m;

              std::string fh_nm = fh->fcn_name ();

              if (fh_nm == octave_fcn_handle::anonymous)
                {
                  std::ostringstream buf;
                  fh->print_raw (buf);
                  m.setfield ("function", buf.str ());

                  m.setfield ("type", "anonymous");
                }
              else
                {
                  m.setfield ("function", fh_nm);

                  if (fcn->is_nested_function ())
                    {
                      m.setfield ("type", "subfunction");
                      Cell parentage (dim_vector (1, 2));
                      parentage.elem(0) = fh_nm;
                      parentage.elem(1) = fcn->parent_fcn_name ();
                      m.setfield ("parentage", octave_value (parentage)); 
                    }
                  else if (fcn->is_private_function ())
                    m.setfield ("type", "private");
                  else if (fh->is_overloaded ())
                    m.setfield ("type", "overloaded");
                  else
                    m.setfield ("type", "simple");
                }

              std::string nm = fcn->fcn_file_name ();

              if (fh_nm == octave_fcn_handle::anonymous)
                {
                  m.setfield ("file", nm);

                  octave_user_function *fu = fh->user_function_value ();

                  std::list<symbol_table::symbol_record> vars
                    = symbol_table::all_variables (fu->scope (), 0);

                  size_t varlen = vars.size ();

                  if (varlen > 0)
                    {
                      octave_scalar_map ws;
                      for (std::list<symbol_table::symbol_record>::const_iterator p = vars.begin ();
                           p != vars.end (); p++)
                        {
                          ws.assign (p->name (), p->varval (0));
                        }

                      m.setfield ("workspace", ws);
                    }
                }
              else if (fcn->is_user_function () || fcn->is_user_script ())
                {
                  octave_function *fu = fh->function_value ();
                  m.setfield ("file", fu->fcn_file_name ());
                }
              else
                m.setfield ("file", "");

              retval = m;
            }
          else
            error ("functions: invalid function handle object");
        }
      else
        error ("functions: argument must be a function handle object");
    }
  else
    print_usage ();

  return retval;
}

DEFUN (func2str, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} func2str (@var{fcn_handle})\n\
Return a string containing the name of the function referenced by\n\
the function handle @var{fcn_handle}.\n\
@end deftypefn")
{
  octave_value retval;

  if (args.length () == 1)
    {
      octave_fcn_handle *fh = args(0).fcn_handle_value ();

      if (! error_state && fh)
        {
          std::string fh_nm = fh->fcn_name ();

          if (fh_nm == octave_fcn_handle::anonymous)
            {
              std::ostringstream buf;

              fh->print_raw (buf);

              retval = buf.str ();
            }
          else
            retval = fh_nm;
        }
      else
        error ("func2str: expecting valid function handle as first argument");
    }
  else
    print_usage ();

  return retval;
}

DEFUN (str2func, args, ,
  "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {} str2func (@var{fcn_name})\n\
@deftypefnx {Built-in Function} {} str2func (@var{fcn_name}, \"global\")\n\
Return a function handle constructed from the string @var{fcn_name}.\n\
If the optional \"global\" argument is passed, locally visible functions\n\
are ignored in the lookup.\n\
@end deftypefn")
{
  octave_value retval;
  int nargin = args.length ();

  if (nargin == 1 || nargin == 2)
    {
      std::string nm = args(0).string_value ();

      if (! error_state)
        retval = make_fcn_handle (nm, nargin != 2);
      else
        error ("str2func: expecting string as first argument");
    }
  else
    print_usage ();

  return retval;
}

/*
%!function y = testrecursionfunc (f, x, n)
%!  if (nargin < 3)
%!    n = 0;
%!  endif
%!  if (n > 2)
%!    y = f (x);
%!  else
%!    n++;
%!    y = testrecursionfunc (@(x) f(2*x), x, n);
%!  endif
%!test
%! assert (testrecursionfunc (@(x) x, 1), 8);
*/

octave_fcn_binder::octave_fcn_binder (const octave_value& f, 
                                      const octave_value& root,
                                      const octave_value_list& templ, 
                                      const std::vector<int>& mask, 
                                      int exp_nargin)
: octave_fcn_handle (f), root_handle (root), arg_template (templ),
  arg_mask (mask), expected_nargin (exp_nargin)
{
}

octave_fcn_handle *
octave_fcn_binder::maybe_binder (const octave_value& f)
{
  octave_fcn_handle *retval = 0;

  octave_user_function *usr_fcn = f.user_function_value (false);
  tree_parameter_list *param_list = usr_fcn ? usr_fcn->parameter_list () : 0;
  
  // Verify that the body is a single expression (always true in theory).
  
  tree_statement_list *cmd_list = usr_fcn ? usr_fcn->body () : 0;
  tree_expression *body_expr = (cmd_list->length () == 1 
                                ? cmd_list->front ()->expression () : 0);


  if (body_expr && body_expr->is_index_expression () 
      && ! (param_list && param_list->takes_varargs ()))
    {
      // It's an index expression.
      tree_index_expression *idx_expr = dynamic_cast<tree_index_expression *> (body_expr);
      tree_expression *head_expr = idx_expr->expression ();
      std::list<tree_argument_list *> arg_lists = idx_expr->arg_lists ();
      std::string type_tags = idx_expr->type_tags ();

      if (type_tags.length () == 1 && type_tags[0] == '('
          && head_expr->is_identifier ())
        {
          assert (arg_lists.size () == 1);

          // It's a single index expression: a(x,y,....)
          tree_identifier *head_id = dynamic_cast<tree_identifier *> (head_expr);
          tree_argument_list *arg_list = arg_lists.front ();

          // Build a map of input params to their position.
          std::map<std::string, int> arginmap;
          int npar = 0;

          if (param_list)
            {
              for (tree_parameter_list::iterator it = param_list->begin ();
                   it != param_list->end (); ++it, ++npar)
                {
                  tree_decl_elt *elt = *it;
                  tree_identifier *id = elt ? elt->ident () : 0;
                  if (id && ! id->is_black_hole ())
                     arginmap[id->name ()] = npar;
                }
            }

          if (arg_list && arg_list->length () > 0)
            {
              bool bad = false;
              int nargs = arg_list->length ();
              octave_value_list arg_template (nargs);
              std::vector<int> arg_mask (nargs);

              // Verify that each argument is either a named param, a constant, or a defined identifier.
              int iarg = 0;
              for (tree_argument_list::iterator it = arg_list->begin ();
                   it != arg_list->end (); ++it, ++iarg)
                {
                  tree_expression *elt = *it;
                  if (elt && elt->is_constant ())
                    {
                      arg_template(iarg) = elt->rvalue1 ();
                      arg_mask[iarg] = -1;
                    }
                  else if (elt && elt->is_identifier ())
                    {
                      tree_identifier *elt_id = dynamic_cast<tree_identifier *> (elt);
                      if (arginmap.find (elt_id->name ()) != arginmap.end ())
                        {
                          arg_mask[iarg] = arginmap[elt_id->name ()];
                        }
                      else if (elt_id->is_defined ())
                        {
                          arg_template(iarg) = elt_id->rvalue1 ();
                          arg_mask[iarg] = -1;
                        }
                      else
                        {
                          bad = true;
                          break;
                        }
                    }
                  else
                    {
                      bad = true;
                      break;
                    }
                }

              octave_value root_val;

              if (! bad)
                {
                  // If the head is a value, use it as root.
                  if (head_id->is_defined ())
                     root_val = head_id->rvalue1 ();
                  else
                    {
                      // It's a name.
                      std::string head_name = head_id->name ();
                      // Function handles can't handle legacy dispatch, so
                      // we make sure it's not defined.
                      if (symbol_table::get_dispatch (head_name).size () > 0)
                         bad = true;
                      else
                        {
                          // Simulate try/catch.
                          unwind_protect frame;
                          interpreter_try (frame);

                          root_val = make_fcn_handle (head_name);
                          if (error_state)
                             bad = true;
                        }
                    }
                }

              if (! bad)
                {
                  // Stash proper name tags.
                  std::list<string_vector> arg_names = idx_expr->arg_names ();
                  assert (arg_names.size () == 1);
                  arg_template.stash_name_tags (arg_names.front ());

                  retval = new octave_fcn_binder (f, root_val, arg_template, 
                                                  arg_mask, npar);
                }
            }
        }
    }

  if (! retval)
     retval = new octave_fcn_handle (f, octave_fcn_handle::anonymous);

  return retval;
}

octave_value_list
octave_fcn_binder::do_multi_index_op (int nargout, 
                                      const octave_value_list& args)
{
  return do_multi_index_op (nargout, args, 0);
}

octave_value_list
octave_fcn_binder::do_multi_index_op (int nargout, 
                                      const octave_value_list& args,
                                      const std::list<octave_lvalue>* lvalue_list)
{
  octave_value_list retval;

  if (args.length () == expected_nargin)
    {
      for (int i = 0; i < arg_template.length (); i++)
        {
          int j = arg_mask[i];
          if (j >= 0)
             arg_template(i) = args(j); // May force a copy...
        }

      // Make a shallow copy of arg_template, to ensure consistency throughout the following
      // call even if we happen to get back here.
      octave_value_list tmp (arg_template);
      retval = root_handle.do_multi_index_op (nargout, tmp, lvalue_list);
    }
  else
     retval = octave_fcn_handle::do_multi_index_op (nargout, args, lvalue_list);

  return retval;
}