pt-assign.h

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////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1996-2023 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"
 
OCTAVE_BEGIN_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;
};
 
OCTAVE_END_NAMESPACE(octave)
 
#endif