oct-lvalue.cc

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////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1996-2021 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// 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
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////
 
#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif
 
#include "error.h"
#include "errwarn.h"
#include "interpreter-private.h"
#include "interpreter.h"
#include "ovl.h"
#include "oct-lvalue.h"
#include "ov.h"
 
namespace octave
{
  bool octave_lvalue::is_defined (void) const
  {
    return ! is_black_hole () && m_frame->is_defined (m_sym);
  }
 
  bool octave_lvalue::is_undefined (void) const
  {
    return ! is_defined ();
  }
 
  void octave_lvalue::define (const octave_value& v)
  {
    m_frame->assign (m_sym, v);
  }
 
  void octave_lvalue::assign (octave_value::assign_op op,
                              const octave_value& rhs)
  {
    if (! is_black_hole ())
      m_frame->assign (op, m_sym, m_type, m_idx, rhs);
  }
 
  octave_idx_type octave_lvalue::numel (void) const
  {
    // Return 1 if there is no index because without an index there
    // should be no way to have a cs-list here.  Cs-lists may be passed
    // around internally but they are not supposed to be stored as
    // single symbols in a stack frame.
 
    size_t num_indices = m_idx.size ();
 
    if (num_indices == 0)
      return 1;
 
    switch (m_type[num_indices-1])
      {
      case '(':
        return 1;
 
      case '{':
        {
          // FIXME: Duplicate code in '.' case below...
 
          // Evaluate, skipping the last index.
 
          std::string tmp_type = m_type;
          std::list<octave_value_list> tmp_idx = m_idx;
 
          tmp_type.pop_back ();
          tmp_idx.pop_back ();
 
          octave_value tmp = eval_for_numel (tmp_type, tmp_idx);
 
          octave_value_list tidx = m_idx.back ();
 
          if (tmp.is_undefined ())
            {
              if (tidx.has_magic_colon ())
                err_invalid_inquiry_subscript ();
 
              tmp = Cell ();
            }
          else if (tmp.is_zero_by_zero ()
                   && (tmp.is_matrix_type () || tmp.is_string ()))
            {
              tmp = Cell ();
            }
 
          return tmp.xnumel (tidx);
        }
        break;
 
      case '.':
        {
          // Evaluate, skipping either the last index or the last two
          // indices if we are looking at "(idx).field".
 
          std::string tmp_type = m_type;
          std::list<octave_value_list> tmp_idx = m_idx;
 
          tmp_type.pop_back ();
          tmp_idx.pop_back ();
 
          bool paren_dot = num_indices > 1 && m_type[num_indices-2] == '(';
 
          // Index for paren operator, if any.
          octave_value_list pidx;
 
          if (paren_dot)
            {
              pidx = tmp_idx.back ();
 
              tmp_type.pop_back ();
              tmp_idx.pop_back ();
            }
 
          octave_value tmp = eval_for_numel (tmp_type, tmp_idx);
 
          bool autoconv = (tmp.is_zero_by_zero ()
                           && (tmp.is_matrix_type () || tmp.is_string ()
                               || tmp.iscell ()));
 
          if (paren_dot)
            {
              // Use octave_map, not octave_scalar_map so that the
              // dimensions are 0x0, not 1x1.
 
              if (tmp.is_undefined ())
                {
                  if (pidx.has_magic_colon ())
                    err_invalid_inquiry_subscript ();
 
                  tmp = octave_map ();
                }
              else if (autoconv)
                tmp = octave_map ();
 
              return tmp.xnumel (pidx);
            }
          else if (tmp.is_undefined () || autoconv)
            return 1;
          else
            return tmp.xnumel (octave_value_list ());
        }
        break;
 
      default:
        panic_impossible ();
      }
  }
 
  void octave_lvalue::set_index (const std::string& t,
                                 const std::list<octave_value_list>& i)
  {
    if (! m_idx.empty ())
      error ("invalid index expression in assignment");
 
    m_type = t;
    m_idx = i;
  }
 
  bool octave_lvalue::index_is_empty (void) const
  {
    bool retval = false;
 
    if (m_idx.size () == 1)
      {
        octave_value_list tmp = m_idx.front ();
 
        retval = (tmp.length () == 1 && tmp(0).isempty ());
      }
 
    return retval;
  }
 
  bool octave_lvalue::index_is_colon (void) const
  {
    bool retval = false;
 
    if (m_idx.size () == 1)
      {
        octave_value_list tmp = m_idx.front ();
 
        retval = (tmp.length () == 1 && tmp(0).is_magic_colon ());
      }
 
    return retval;
  }
 
  void octave_lvalue::do_unary_op (octave_value::unary_op op)
  {
    if (! is_black_hole ())
      m_frame->do_non_const_unary_op (op, m_sym, m_type, m_idx);
  }
 
  octave_value octave_lvalue::value (void) const
  {
    return (is_black_hole ()
            ? octave_value () : m_frame->value (m_sym, m_type, m_idx));
  }
 
  octave_value
  octave_lvalue::eval_for_numel (const std::string& type,
                                 const std::list<octave_value_list>& idx) const
  {
    octave_value retval;
 
    try
      {
        retval = m_frame->varval (m_sym);
 
        if (retval.is_constant () && ! idx.empty ())
          retval = retval.subsref (type, idx);
      }
    catch (const execution_exception&)
      {
        // Ignore an error and treat it as undefined.  The error
        // could happen because there is an index is out of range
        // and we will be resizing a cell array.
 
        interpreter& interp
          = __get_interpreter__ ("octave_lvalue::eval_for_numel");
 
        interp.recover_from_exception ();
 
        retval = octave_value ();
      }
 
    return retval;
  }
}