/*

Copyright (C) 1996-2016 John W. Eaton

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/>.

*/

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include <iostream>
#include <string>

#include "error.h"
#include "pager.h"
#include "oct-lvalue.h"
#include "ov.h"
#include "pt-exp.h"

namespace octave
{
  // Expressions.

  bool
  tree_expression::is_logically_true (const char *warn_for)
  {
    bool expr_value = false;

    octave_value t1 = rvalue1 ();

    if (t1.is_defined ())
      return t1.is_true ();
    else
      error ("%s: undefined value used in conditional expression", warn_for);

    return expr_value;
  }

  octave_value
  tree_expression::rvalue1 (int)
  {
    error ("invalid rvalue function called in expression");
  }

  octave_value_list
  tree_expression::rvalue (int)
  {
    error ("invalid rvalue function called in expression");
  }

  octave_value_list
  tree_expression::rvalue (int nargout, const std::list<octave_lvalue> *)
  {
    return rvalue (nargout);
  }

  octave_lvalue
  tree_expression::lvalue (void)
  {
    error ("invalid lvalue function called in expression");
  }

  std::string
  tree_expression::original_text (void) const
  {
    return "";
  }
}