/*

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 "error.h"
#include "defun.h"
#include "ovl.h"
#include "ov.h"
#include "profiler.h"
#include "pt-binop.h"
#include "pt-bp.h"
#include "pt-walk.h"
#include "variables.h"

namespace octave
{
  // Binary expressions.

  octave_value_list
  tree_binary_expression::rvalue (int nargout)
  {
    octave_value_list retval;

    if (nargout > 1)
      error ("binary operator '%s': invalid number of output arguments",
             oper ().c_str ());

    retval = rvalue1 (nargout);

    return retval;
  }

  void
  tree_binary_expression::matlab_style_short_circuit_warning (const char *op)
  {
    warning_with_id ("Octave:possible-matlab-short-circuit-operator",
                     "Matlab-style short-circuit operation performed for operator %s",
                     op);

    braindead_shortcircuit_warning_issued = true;
  }

  octave_value
  tree_binary_expression::rvalue1 (int)
  {
    octave_value retval;

    if (eligible_for_braindead_shortcircuit)
      {
        if (op_lhs)
          {
            octave_value a = op_lhs->rvalue1 ();

            if (a.ndims () == 2 && a.rows () == 1 && a.columns () == 1)
              {
                bool result = false;

                bool a_true = a.is_true ();

                if (a_true)
                  {
                    if (etype == octave_value::op_el_or)
                      {
                        matlab_style_short_circuit_warning ("|");
                        return octave_value (true);
                      }
                  }
                else
                  {
                    if (etype == octave_value::op_el_and)
                      {
                        matlab_style_short_circuit_warning ("&");
                        return octave_value (false);
                      }
                  }

                if (op_rhs)
                  {
                    octave_value b = op_rhs->rvalue1 ();

                    result = b.is_true ();
                  }

                return octave_value (result);
              }
          }
      }

    if (op_lhs)
      {
        octave_value a = op_lhs->rvalue1 ();

        if (a.is_defined () && op_rhs)
          {
            octave_value b = op_rhs->rvalue1 ();

            if (b.is_defined ())
              {
                BEGIN_PROFILER_BLOCK (tree_binary_expression)

                  // Note: The profiler does not catch the braindead
                  // short-circuit evaluation code above, but that should be
                  // ok.  The evaluation of operands and the operator itself
                  // is entangled and it's not clear where to start/stop
                  // timing the operator to make it reasonable.

                  retval = ::do_binary_op (etype, a, b);

                END_PROFILER_BLOCK
                  }
          }
      }

    return retval;
  }

  std::string
  tree_binary_expression::oper (void) const
  {
    return octave_value::binary_op_as_string (etype);
  }

  tree_expression *
  tree_binary_expression::dup (symbol_table::scope_id scope,
                               symbol_table::context_id context) const
  {
    tree_binary_expression *new_be
      = new tree_binary_expression (op_lhs ? op_lhs->dup (scope, context) : 0,
                                    op_rhs ? op_rhs->dup (scope, context) : 0,
                                    line (), column (), etype);

    new_be->copy_base (*this);

    return new_be;
  }

  void
  tree_binary_expression::accept (tree_walker& tw)
  {
    tw.visit_binary_expression (*this);
  }

  // Boolean expressions.

  octave_value_list
  tree_boolean_expression::rvalue (int nargout)
  {
    octave_value_list retval;

    if (nargout > 1)
      error ("binary operator '%s': invalid number of output arguments",
             oper ().c_str ());

    retval = rvalue1 (nargout);

    return retval;
  }

  octave_value
  tree_boolean_expression::rvalue1 (int)
  {
    octave_value retval;

    bool result = false;

    // This evaluation is not caught by the profiler, since we can't find
    // a reasonable place where to time.  Note that we don't want to
    // include evaluation of LHS or RHS into the timing, but this is
    // entangled together with short-circuit evaluation here.

    if (op_lhs)
      {
        octave_value a = op_lhs->rvalue1 ();

        bool a_true = a.is_true ();

        if (a_true)
          {
            if (etype == bool_or)
              return octave_value (true);
          }
        else
          {
            if (etype == bool_and)
              return octave_value (false);
          }

        if (op_rhs)
          {
            octave_value b = op_rhs->rvalue1 ();

            result = b.is_true ();
          }

        retval = octave_value (result);
      }

    return retval;
  }

  std::string
  tree_boolean_expression::oper (void) const
  {
    std::string retval = "<unknown>";

    switch (etype)
      {
      case bool_and:
        retval = "&&";
        break;

      case bool_or:
        retval = "||";
        break;

      default:
        break;
      }

    return retval;
  }

  tree_expression *
  tree_boolean_expression::dup (symbol_table::scope_id scope,
                                symbol_table::context_id context) const
  {
    tree_boolean_expression *new_be
      = new tree_boolean_expression (op_lhs ? op_lhs->dup (scope, context) : 0,
                                     op_rhs ? op_rhs->dup (scope, context) : 0,
                                     line (), column (), etype);

    new_be->copy_base (*this);

    return new_be;
  }
}