/*

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 (octave_pt_id_h)
#define octave_pt_id_h 1

#include "octave-config.h"

#include <iosfwd>
#include <string>

class octave_value;
class octave_value_list;
class octave_function;

#include "oct-lvalue.h"
#include "pt-bp.h"
#include "pt-exp.h"
#include "symtab.h"

namespace octave
{
  class tree_walker;

  // Symbols from the symbol table.

  class tree_identifier : public tree_expression
  {
    friend class tree_index_expression;

  public:

    tree_identifier (int l = -1, int c = -1)
      : tree_expression (l, c) { }

    tree_identifier (const symbol_table::symbol_record& s,
                     int l = -1, int c = -1,
                     symbol_table::scope_id sc = symbol_table::current_scope ())
      : tree_expression (l, c), sym (s, sc) { }

    // No copying!

    tree_identifier (const tree_identifier&) = delete;

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

    ~tree_identifier (void) = default;

    bool has_magic_end (void) const { return (name () == "end"); }

    bool is_identifier (void) const { return true; }

    // The name doesn't change with scope, so use sym instead of
    // accessing it through sym so that this function may remain const.
    std::string name (void) const { return sym.name (); }

    bool is_defined (void) { return sym->is_defined (); }

    virtual bool is_variable (void) const { return sym->is_variable (); }

    virtual bool is_black_hole (void) { return false; }

    // Try to find a definition for an identifier.  Here's how:
    //
    //   * If the identifier is already defined and is a function defined
    //     in an function file that has been modified since the last time
    //     we parsed it, parse it again.
    //
    //   * If the identifier is not defined, try to find a builtin
    //     variable or an already compiled function with the same name.
    //
    //   * If the identifier is still undefined, try looking for an
    //     function file to parse.
    //
    //   * On systems that support dynamic linking, we prefer .oct files,
    //     then .mex files, then .m files.

    octave_value
    do_lookup (const octave_value_list& args = octave_value_list ())
    {
      return sym->find (args);
    }

    void mark_global (void) { sym->mark_global (); }

    void mark_as_static (void) { sym->init_persistent (); }

    void mark_as_formal_parameter (void) { sym->mark_formal (); }

    // We really need to know whether this symbol referst to a variable
    // or a function, but we may not know that yet.

    bool lvalue_ok (void) const { return true; }

    octave_value rvalue1 (int nargout = 1);

    octave_value_list rvalue (int nargout)
    {
      return rvalue (nargout, 0);
    }

    octave_value_list rvalue (int nargout,
                              const std::list<octave_lvalue> *lvalue_list);

    octave_lvalue lvalue (void);

    void eval_undefined_error (void);

    void static_workspace_error (void)
    {
      error ("can not add variable \"%s\" to a static workspace",
             name ().c_str ());
    }

    tree_identifier *dup (symbol_table::scope_id scope,
                          symbol_table::context_id context) const;

    void accept (tree_walker& tw);

    symbol_table::symbol_reference symbol (void) const
    {
      return sym;
    }
  private:

    // The symbol record that this identifier references.
    symbol_table::symbol_reference sym;
  };

  class tree_black_hole : public tree_identifier
  {
  public:

    tree_black_hole (int l = -1, int c = -1)
      : tree_identifier (l, c) { }

    std::string name (void) const { return "~"; }

    bool is_variable (void) const { return false; }

    bool is_black_hole (void) { return true; }

    tree_black_hole *dup (symbol_table::scope_id,
                          symbol_table::context_id) const
    {
      return new tree_black_hole;
    }

    octave_lvalue lvalue (void)
    {
      return octave_lvalue (); // black hole lvalue
    }
  };
}

#if defined (OCTAVE_USE_DEPRECATED_FUNCTIONS)

OCTAVE_DEPRECATED ("use 'octave::tree_identifier' instead")
typedef octave::tree_identifier tree_identifier;

OCTAVE_DEPRECATED ("use 'octave::tree_black_hole' instead")
typedef octave::tree_black_hole tree_black_hole;

#endif

#endif