////////////////////////////////////////////////////////////////////////
//
// 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 (octave_pt_assign_h)
#define octave_pt_assign_h 1

#include "octave-config.h"

#include <iosfwd>
#include <string>

class octave_value;
class octave_value_list;

#include "ov.h"
#include "pt-exp.h"
#include "pt-walk.h"

namespace octave
{
  class symbol_scope;
  class octave_lvalue;
  class tree_argument_list;

  // Simple assignment expressions.

  class tree_simple_assignment : public tree_expression
  {
  public:

    tree_simple_assignment (bool plhs = false, int l = -1, int c = -1,
                            octave_value::assign_op t = octave_value::op_asn_eq)
      : tree_expression (l, c), m_lhs (nullptr), m_rhs (nullptr),
        m_preserve (plhs), m_ans_assign (), m_etype (t)
    { }

    tree_simple_assignment (tree_expression *le, tree_expression *re,
                            bool plhs = false, int l = -1, int c = -1,
                            octave_value::assign_op t = octave_value::op_asn_eq);

    // No copying!

    tree_simple_assignment (const tree_simple_assignment&) = delete;

    tree_simple_assignment& operator = (const tree_simple_assignment&) = delete;

    ~tree_simple_assignment (void);

    bool rvalue_ok (void) const { return true; }

    bool is_assignment_expression (void) const { return true; }

    std::string oper (void) const;

    tree_expression * left_hand_side (void) { return m_lhs; }

    tree_expression * right_hand_side (void) { return m_rhs; }

    tree_expression * dup (symbol_scope& scope) const;

    octave_value evaluate (tree_evaluator& tw, int nargout = 1);

    octave_value_list evaluate_n (tree_evaluator& tw, int nargout = 1)
    {
      return ovl (evaluate (tw, nargout));
    }

    void accept (tree_walker& tw)
    {
      tw.visit_simple_assignment (*this);
    }

    octave_value::assign_op op_type (void) const { return m_etype; }

  private:

    void do_assign (octave_lvalue& ult, const octave_value_list& args,
                    const octave_value& rhs_val);

    void do_assign (octave_lvalue& ult, const octave_value& rhs_val);

    // The left hand side of the assignment.
    tree_expression *m_lhs;

    // The right hand side of the assignment.
    tree_expression *m_rhs;

    // True if we should not delete the lhs.
    bool m_preserve;

    // True if this is an assignment to the automatic variable ans.
    bool m_ans_assign;

    // The type of the expression.
    octave_value::assign_op m_etype;
  };

  // Multi-valued assignment expressions.

  class tree_multi_assignment : public tree_expression
  {
  public:

    tree_multi_assignment (bool plhs = false, int l = -1, int c = -1)
      : tree_expression (l, c), m_lhs (nullptr), m_rhs (nullptr),
        m_preserve (plhs)
    { }

    tree_multi_assignment (tree_argument_list *lst, tree_expression *r,
                           bool plhs = false, int l = -1, int c = -1);

    // No copying!

    tree_multi_assignment (const tree_multi_assignment&) = delete;

    tree_multi_assignment& operator = (const tree_multi_assignment&) = delete;

    ~tree_multi_assignment (void);

    bool is_assignment_expression (void) const { return true; }

    bool rvalue_ok (void) const { return true; }

    std::string oper (void) const;

    tree_argument_list * left_hand_side (void) { return m_lhs; }

    tree_expression * right_hand_side (void) { return m_rhs; }

    tree_expression * dup (symbol_scope& scope) const;

    octave_value evaluate (tree_evaluator& tw, int nargout = 1)
    {
      octave_value_list retval = evaluate_n (tw, nargout);

      return retval.length () > 0 ? retval(0) : octave_value ();
    }

    octave_value_list evaluate_n (tree_evaluator& tw, int nargout = 1);

    void accept (tree_walker& tw)
    {
      tw.visit_multi_assignment (*this);
    }

    octave_value::assign_op op_type (void) const
    {
      return octave_value::op_asn_eq;
    }

  private:

    // The left hand side of the assignment.
    tree_argument_list *m_lhs;

    // The right hand side of the assignment.
    tree_expression *m_rhs;

    // True if we should not delete the lhs.
    bool m_preserve;
  };
}

#endif
