////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1996-2022 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/>.
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////////////////////////////////////////////////////////////////////////

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "error.h"
#include "pt-all.h"
#include "pt-anon-scopes.h"

// TODO: make sure that if(f->scope()) is checked if necessary

namespace octave
{
  tree_anon_scopes::tree_anon_scopes (tree_anon_fcn_handle& anon_fh)
    : tree_walker (), m_params (), m_vars ()
  {
    visit_anon_fcn_handle (anon_fh);
  }

  void
  tree_anon_scopes::visit_anon_fcn_handle (tree_anon_fcn_handle& afh)
  {
    tree_parameter_list *param_list = afh.parameter_list ();
    tree_expression *expr = afh.expression ();

    // Collect names of parameters.

    if (param_list)
      {
        std::list<std::string> pnames = param_list->variable_names ();

        for (const auto& nm : pnames)
          m_params.insert (nm);

        // Hmm, should this be included in the list returned from
        // tree_parameter_list::variable_names?
        if (param_list->takes_varargs ())
          m_params.insert ("varargin");
      }

    // Further walk the tree to find free variables in this expression
    // and any nested definitions of additional anonymous functions.

    if (expr)
      expr->accept (*this);
  }

  // The rest of visit_... methods is only for walking the tree.  Many of
  // them, in particular all methods for commands, are not applicable to
  // anonymous functions.  Only parts of the tree are walked which could
  // contain further (nested) anonymous function definitions (so
  // e.g. identifiers and left hand sides of assignments are ignored).

  void
  tree_anon_scopes::visit_identifier (tree_identifier& id)
  {
    std::string nm = id.name ();

    if (m_params.find (nm) == m_params.end ())
      m_vars.insert (nm);
  }

  void
  tree_anon_scopes::visit_parameter_list (tree_parameter_list&)
  {
    // In visit_anon_fcn_handle we only accept/visit the body of
    // anonymous function definitions, not the parameter list.

    panic_impossible ();
  }

  void
  tree_anon_scopes::visit_statement (tree_statement& stmt)
  {
    tree_command *cmd = stmt.command ();

    if (cmd)
      panic_impossible ();
    else
      {
        tree_expression *expr = stmt.expression ();

        if (expr)
          expr->accept (*this);
      }
  }

  void
  tree_anon_scopes::visit_statement_list (tree_statement_list& lst)
  {
    for (auto& p : lst)
      {
        tree_statement *elt = p;

        if (elt)
          elt->accept (*this);
      }
  }
}