/* -*-comment-start: "//";comment-end:""-*-
 * GNU Mes --- Maxwell Equations of Software
 * Copyright © 2018 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 *
 * This file is part of GNU Mes.
 *
 * GNU Mes 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.
 *
 * GNU Mes 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 GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
 */

SCM struct_ref_ (SCM x, long i);
SCM struct_set_x_ (SCM x, long i, SCM e);
SCM cstring_to_symbol (char const *s);

SCM
make_module_type () ///(internal))
{
  SCM record_type = cell_symbol_record_type; // FIXME
  SCM fields = cell_nil;
  fields = cons (cstring_to_symbol ("globals"), fields);
  fields = cons (cstring_to_symbol ("locals"), fields);
  fields = cons (cstring_to_symbol ("name"), fields);
  fields = cons (fields, cell_nil);
  fields = cons (cell_symbol_module, fields);
  return make_struct (record_type, fields, cell_unspecified);
}

SCM
make_initial_module (SCM a) ///((internal))
{
  SCM module_type = make_module_type ();
  a = acons (cell_symbol_module, module_type, a);

  SCM hashq_type = make_hashq_type ();
  a = acons (cell_symbol_hashq_table, hashq_type, a);

  SCM name = cons (cstring_to_symbol ("boot"), cell_nil);
  SCM globals = make_hash_table_ (0);
  SCM locals = cell_nil;

  SCM values = cell_nil;
  values = cons (globals, values);
  values = cons (locals, values);
  values = cons (name, values);
  values = cons (cell_symbol_module, values);
  SCM module = make_struct (module_type, values, cstring_to_symbol ("module-printer"));
  r0 = cell_nil;
  r0 = cons (CADR (a), r0);
  r0 = cons (CAR (a), r0);
  m0 = module;
  while (TYPE (a) == TPAIR)
    {
      module_define_x (module, CAAR (a), CDAR (a));
      a = CDR (a);
    }

  return module;
}

SCM
module_printer (SCM module)
{
  //module = m0;
  fdputs ("#<", __stdout); display_ (struct_ref_ (module, 2)); fdputc (' ', __stdout);
  fdputs ("name: ", __stdout); display_ (struct_ref_ (module, 3)); fdputc (' ', __stdout);
  fdputs ("locals: ", __stdout); display_ (struct_ref_ (module, 4)); fdputc (' ', __stdout);
  SCM table = struct_ref_ (module, 5);
  fdputs ("globals:\n  ", __stdout);
  display_ (table);
  fdputc ('>', __stdout);
}

SCM
module_variable (SCM module, SCM name)
{
  //SCM locals = struct_ref_ (module, 3);
  SCM locals = module;
  SCM x = assq (name, locals);
  if (x == cell_f)
    {
      module = m0;
      SCM globals = struct_ref_ (module, 5);
      x = hashq_get_handle (globals, name, cell_f);
    }
  return x;
}

SCM
module_ref (SCM module, SCM name)
{
  SCM x = module_variable (module, name);
  if (x == cell_f)
    return cell_undefined;
  return CDR (x);
}

SCM
module_define_x (SCM module, SCM name, SCM value)
{
  module = m0;
  SCM globals = struct_ref_ (module, 5);
  return hashq_set_x (globals, name, value);
}