/*	Copyright (C) 1998 Free Software Foundation, Inc.
 * 
 * This program 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 2, or (at your option)
 * any later version.
 * 
 * This program 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 this software; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307 USA
 *
 * As a special exception, the Free Software Foundation gives permission
 * for additional uses of the text contained in its release of GUILE.
 *
 * The exception is that, if you link the GUILE library with other files
 * to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * Your use of that executable is in no way restricted on account of
 * linking the GUILE library code into it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU General Public License.
 *
 * This exception applies only to the code released by the
 * Free Software Foundation under the name GUILE.  If you copy
 * code from other Free Software Foundation releases into a copy of
 * GUILE, as the General Public License permits, the exception does
 * not apply to the code that you add in this way.  To avoid misleading
 * anyone as to the status of such modified files, you must delete
 * this exception notice from them.
 *
 * If you write modifications of your own for GUILE, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.  */

/* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
   gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */



#include "_scm.h"

#include "eval.h"
#include "procprop.h"

#include "modules.h"

static SCM the_root_module;
static SCM root_module_lookup_closure;

SCM
scm_the_root_module ()
{
  return SCM_CDR (the_root_module);
}

static SCM the_module;

SCM
scm_selected_module ()
{
  return SCM_CDR (the_module);
}

static SCM set_current_module;

SCM
scm_select_module (SCM module)
{
  SCM old = scm_selected_module ();
  scm_apply (SCM_CDR (set_current_module), SCM_LIST1 (module), SCM_EOL);
  return old;
}

SCM_SYMBOL (scm_sym_app, "app");
SCM_SYMBOL (scm_sym_modules, "modules");
static SCM module_prefix;

static SCM
scm_module_full_name (SCM name)
{
  if (SCM_CAR (name) == scm_sym_app)
    return name;
  else
    return scm_append (SCM_LIST2 (module_prefix, name));
}

static SCM make_modules_in;
static SCM beautify_user_module_x;

SCM
scm_make_module (SCM name)
{
  return scm_apply (SCM_CDR (make_modules_in),
		    SCM_LIST2 (scm_the_root_module (),
			       scm_module_full_name (name)),
		    SCM_EOL);
}

SCM
scm_ensure_user_module (SCM module)
{
  scm_apply (SCM_CDR (beautify_user_module_x), SCM_LIST1 (module), SCM_EOL);
  return SCM_UNSPECIFIED;
}

static SCM module_eval_closure;

SCM
scm_module_lookup_closure (SCM module)
{
  return scm_apply (SCM_CDR (module_eval_closure),
		    SCM_LIST1 (module),
		    SCM_EOL);
}

static SCM resolve_module;

SCM
scm_resolve_module (SCM name)
{
  return scm_apply (SCM_CDR (resolve_module), SCM_LIST1 (name), SCM_EOL);
}

static SCM try_module_autoload;

SCM
scm_load_scheme_module (SCM name)
{
  return scm_apply (SCM_CDR (try_module_autoload), SCM_LIST1 (name), SCM_EOL);
}

/* Environments
 */

SCM
scm_top_level_env (SCM thunk)
{
  if (SCM_IMP (thunk))
    return SCM_EOL;
  else
    return scm_cons (thunk, SCM_EOL);
}

SCM
scm_env_top_level (SCM env)
{
  while (SCM_NIMP (env))
    {
      if (!SCM_CONSP (SCM_CAR (env))
	  && SCM_NFALSEP (scm_procedure_p (SCM_CAR (env))))
	return SCM_CAR(env);
      env = SCM_CDR (env);
    }
  return SCM_BOOL_F;
}


SCM_SYMBOL (scm_sym_system_module, "system-module");

SCM
scm_system_module_env_p (SCM env)
{
  SCM proc = scm_env_top_level (env);
  if (SCM_FALSEP (proc))
    proc = root_module_lookup_closure;
  return ((SCM_NFALSEP (scm_procedure_property (proc,
						scm_sym_system_module)))
	  ? SCM_BOOL_T
	  : SCM_BOOL_F);
}

void
scm_init_modules ()
{
#include "modules.x"
}

void
scm_post_boot_init_modules ()
{
  the_root_module = scm_intern0 ("the-root-module");
  the_module = scm_intern0 ("the-module");
  set_current_module = scm_intern0 ("set-current-module");
  module_prefix = scm_permanent_object (SCM_LIST2 (scm_sym_app,
						   scm_sym_modules));
  make_modules_in = scm_intern0 ("make-modules-in");
  beautify_user_module_x = scm_intern0 ("beautify-user-module!");
  module_eval_closure = scm_intern0 ("module-eval-closure");
  root_module_lookup_closure = scm_permanent_object
    (scm_module_lookup_closure (SCM_CDR (the_root_module)));
  resolve_module = scm_intern0 ("resolve-module");
  try_module_autoload = scm_intern0 ("try-module-autoload");
}