mes/mes.c

/* -*-comment-start: "//";comment-end:""-*-
 * Mes --- Maxwell Equations of Software
 * Copyright © 2016 Jan Nieuwenhuizen <janneke@gnu.org>
 *
 * This file is part of Mes.
 *
 * 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.
 *
 * 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 Mes.  If not, see <http://www.gnu.org/licenses/>.
 */

#define _GNU_SOURCE
#include <assert.h>
#include <ctype.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>

#define DEBUG 0
#define QUASIQUOTE 1
//#define QUASISYNTAX 0

#define GC 1
#define MES_FULL 1
#define MES_MINI 0 // 1 for gc-2a.test, gc-3.test

#if MES_FULL
int ARENA_SIZE = 400000000; // need this much for scripts/mescc.mes
//int ARENA_SIZE = 300000000; // need this much for tests/match.scm
//int ARENA_SIZE = 30000000; // need this much for tests/record.scm
//int ARENA_SIZE = 500000; // enough for tests/scm.test
//int ARENA_SIZE = 60000; // enough for tests/base.test
int GC_SAFETY = 10000;
int GC_FREE = 20000;
#else
//int ARENA_SIZE = 500; // MINI
int ARENA_SIZE = 4000; // MES_MINI, gc-3.test
//int ARENA_SIZE = 10000; // gc-2a.test
//int ARENA_SIZE = 18000; // gc-2.test -->KRAK
//int ARENA_SIZE = 23000; // gc-2.test OK
// int GC_SAFETY = 1000;
// int GC_FREE = 1000;
int GC_SAFETY = 10;
int GC_FREE = 10;
#endif

typedef long SCM;
enum type_t {CHAR, FUNCTION, MACRO, NUMBER, PAIR, SPECIAL, STRING, SYMBOL, REF, VALUES, VECTOR, BROKEN_HEART};
typedef SCM (*function0_t) (void);
typedef SCM (*function1_t) (SCM);
typedef SCM (*function2_t) (SCM, SCM);
typedef SCM (*function3_t) (SCM, SCM, SCM);
typedef SCM (*functionn_t) (SCM);
typedef struct function_t {
  union {
    function0_t function0;
    function1_t function1;
    function2_t function2;
    function3_t function3;
    functionn_t functionn;
  };
  int arity;
} function;
struct scm_t;
typedef struct scm_t {
  enum type_t type;
  union {
    char const *name;
    SCM string;
    SCM car;
    SCM ref;
    int length;
  };
  union {
    int value;
    int function;
    SCM cdr;
    SCM macro;
    SCM vector;
    int hits;
  };
} scm;

function functions[200];
int g_function = 0;

#include "mes.symbols.h"
#include "define.h"
#include "lib.h"
#include "math.h"
#include "mes.h"
#include "posix.h"
#include "quasiquote.h"
#include "string.h"
#include "type.h"

SCM display_ (FILE* f, SCM x);
SCM display_helper (FILE*, SCM , bool, char const*, bool);

SCM symbols = 0;
SCM stack = 0;
SCM r0 = 0; // a/env
SCM r1 = 0; // param 1
SCM r2 = 0; // param 2
SCM r3 = 0; // param 3

scm scm_nil = {SPECIAL, "()"};
scm scm_f = {SPECIAL, "#f"};
scm scm_t = {SPECIAL, "#t"};
scm scm_dot = {SPECIAL, "."};
scm scm_undefined = {SPECIAL, "*undefined*"};
scm scm_unspecified = {SPECIAL, "*unspecified*"};
scm scm_closure = {SPECIAL, "*closure*"};
scm scm_circular = {SPECIAL, "*circular*"};
#if BOOT
scm scm_label = {
  SPECIAL, "label"};
#endif
scm scm_begin = {SPECIAL, "*begin*"};

scm scm_symbol_lambda = {SYMBOL, "lambda"};
scm scm_symbol_begin = {SYMBOL, "begin"};
scm scm_symbol_if = {SYMBOL, "if"};
scm scm_symbol_define = {SYMBOL, "define"};
scm scm_symbol_define_macro = {SYMBOL, "define-macro"};
scm scm_symbol_set_x = {SYMBOL, "set!"};

scm scm_symbol_quote = {SYMBOL, "quote"};
scm scm_symbol_quasiquote = {SYMBOL, "quasiquote"};
scm scm_symbol_unquote = {SYMBOL, "unquote"};
scm scm_symbol_unquote_splicing = {SYMBOL, "unquote-splicing"};

scm scm_symbol_sc_expand = {SYMBOL, "sc-expand"};
scm scm_symbol_expand_macro = {SYMBOL, "expand-macro"};
scm scm_symbol_sc_expander_alist = {SYMBOL, "*sc-expander-alist*"};
scm scm_symbol_noexpand = {SYMBOL, "noexpand"};
scm scm_symbol_syntax = {SYMBOL, "syntax"};
scm scm_symbol_quasisyntax = {SYMBOL, "quasisyntax"};
scm scm_symbol_unsyntax = {SYMBOL, "unsyntax"};
scm scm_symbol_unsyntax_splicing = {SYMBOL, "unsyntax-splicing"};

scm scm_symbol_call_with_values = {SYMBOL, "call-with-values"};
scm scm_symbol_current_module = {SYMBOL, "current-module"};
scm scm_symbol_primitive_load = {SYMBOL, "primitive-load"};

scm char_nul = {CHAR, .name="nul", .value=0};
scm char_backspace = {CHAR, .name="backspace", .value=8};
scm char_tab = {CHAR, .name="tab", .value=9};
scm char_newline = {CHAR, .name="newline", .value=10};
scm char_vt = {CHAR, .name="vt", .value=11};
scm char_page = {CHAR, .name="page", .value=12};
scm char_return = {CHAR, .name="return", .value=13};
scm char_space = {CHAR, .name="space", .value=32};

scm g_free = {NUMBER, .value=0};
scm *g_cells;
scm *g_news = 0;

#define CAR(x) g_cells[x].car
#define CDR(x) g_cells[x].cdr
#define HITS(x) g_cells[x].hits
#define LENGTH(x) g_cells[x].length
#define NAME(x) g_cells[x].name
#define STRING(x) g_cells[x].string
#define TYPE(x) g_cells[x].type
#define MACRO(x) g_cells[x].macro
#define REF(x) g_cells[x].ref
#define VALUE(x) g_cells[x].value
#define VECTOR(x) g_cells[x].vector
#define FUNCTION(x) functions[g_cells[x].function]
#define NCAR(x) g_news[x].car
#define NTYPE(x) g_news[x].type

#define CAAR(x) CAR (CAR (x))
#define CDAR(x) CDR (CAR (x))
#define CAAR(x) CAR (CAR (x))
#define CADAR(x) CAR (CDR (CAR (x)))
#define CDADAR(x) CAR (CDR (CAR (CDR (x))))
#define CADR(x) CAR (CDR (x))

SCM
car (SCM x)
{
  assert (TYPE (x) == PAIR);
  return CAR (x);
}

SCM
cdr (SCM x)
{
  assert (TYPE (x) == PAIR);
  return CDR (x);
}

SCM
gc_alloc (int n)
{
  assert (g_free.value + n < ARENA_SIZE);
  SCM x = g_free.value;
  g_free.value += n;
  return x;
}

SCM g_start;
scm *
gc_news ()
{
  g_news = (scm *)malloc (ARENA_SIZE*sizeof(scm));
  g_news[0].type = VECTOR;
  g_news[0].length = 1000;
  g_news[0].vector = 0;
  g_news++;
  g_news[0].type = CHAR;
  g_news[0].value = 'n';
  return g_news;
}

SCM
gc ()
{
  fprintf (stderr, "***gc[%d]...", g_free.value);
  g_free.value = 1;
  if (!g_news)
    gc_news ();
  for (int i=g_free.value; i<g_start; i++)
    gc_copy (i);
  symbols = gc_copy (symbols);
  SCM new = gc_copy (stack);
  fprintf (stderr, "new=%d, start=%d\n", new, stack);
  stack = new;
  return gc_loop (1);
}

SCM
gc_loop (SCM scan)
{
  while (scan < g_free.value)
    {
      if (NTYPE (scan) == MACRO
          || NTYPE (scan) == PAIR
          || NTYPE (scan) == REF
          || scan == 1
          || ((NTYPE (scan) == SPECIAL && TYPE (NCAR (scan)) == PAIR)
              || (NTYPE (scan) == STRING && TYPE (NCAR (scan)) == PAIR)
              || (NTYPE (scan) == SYMBOL && TYPE (NCAR (scan)) == PAIR)))
        {
          SCM car = gc_copy (g_news[scan].car);
          gc_relocate_car (scan, car);
        }
      if ((NTYPE (scan) == MACRO
           || NTYPE (scan) == PAIR
           || NTYPE (scan) == VALUES)
          && g_news[scan].cdr) // allow for 0 terminated list of symbols
        {
          SCM cdr = gc_copy (g_news[scan].cdr);
          gc_relocate_cdr (scan, cdr);
        }
      scan++;
    }
  return gc_flip ();
}

SCM
gc_copy (SCM old)
{
  if (TYPE (old) == BROKEN_HEART) return g_cells[old].car;
  SCM new = g_free.value++;
  g_news[new] = g_cells[old];
  if (NTYPE (new) == VECTOR)
    {
      g_news[new].vector = g_free.value;
      for (int i=0; i<LENGTH (old); i++)
        g_news[g_free.value++] = g_cells[VECTOR (old)+i];
    }
  g_cells[old].type = BROKEN_HEART;
  g_cells[old].car = new;
  return new;
}

SCM
gc_relocate_car (SCM new, SCM car)
{
  g_news[new].car = car;
  return cell_unspecified;
}

SCM
gc_relocate_cdr (SCM new, SCM cdr)
{
  g_news[new].cdr = cdr;
  return cell_unspecified;
}

SCM
gc_flip ()
{
  scm *cells = g_cells;
  g_cells = g_news;
  g_news = cells;
  fprintf (stderr, " => jam[%d]\n", g_free.value);
  return stack;
}

SCM
gc_show ()
{
  fprintf (stderr, "cells: ");
  scm *t = g_cells;
  display_ (stderr, -1);
  fprintf (stderr, "\n");
  if (g_news)
    {
      fprintf (stderr, "news: ");
      g_cells = g_news;
      display_ (stderr, -1);
      fprintf (stderr, "\n");
    }
  g_cells = t;
  return cell_unspecified;
}

SCM tmp;
SCM tmp_num;
SCM tmp_num2;
SCM tmp_num3;
SCM tmp_num4;

SCM
make_cell (SCM type, SCM car, SCM cdr)
{
  SCM x = gc_alloc (1);
  assert (TYPE (type) == NUMBER);
  TYPE (x) = VALUE (type);
  if (VALUE (type) == CHAR || VALUE (type) == NUMBER) {
    if (car) CAR (x) = CAR (car);
    if (cdr) CDR (x) = CDR (cdr);
  } else if (VALUE (type) == FUNCTION) {
    if (car) CAR (x) = car;
    if (cdr) CDR (x) = CDR (cdr);
  } else {
    CAR (x) = car;
    CDR (x) = cdr;
  }
  return x;
}

SCM
cons (SCM x, SCM y)
{
  g_cells[tmp_num].value = PAIR;
  return make_cell (tmp_num, x, y);
}

SCM
eq_p (SCM x, SCM y)
{
  return (x == y
          || (TYPE (x) == CHAR && TYPE (y) == CHAR
              && VALUE (x) == VALUE (y))
          || (TYPE (x) == NUMBER && TYPE (y) == NUMBER
              && VALUE (x) == VALUE (y)))
    ? cell_t : cell_f;
}

SCM
set_car_x (SCM x, SCM e)
{
  assert (TYPE (x) == PAIR);
  CAR (x) = e;
  return cell_unspecified;
}

SCM
set_cdr_x (SCM x, SCM e)
{
  assert (TYPE (x) == PAIR);
  cache_invalidate (cdr (x));
  CDR (x) = e;
  return cell_unspecified;
}

SCM
set_env_x (SCM x, SCM e, SCM a)
{
  cache_invalidate (x);
  SCM p = assert_defined (x, assq (x, a));
  return set_cdr_x (p, e);
}

SCM
quote (SCM x)
{
  return cons (cell_symbol_quote, x);
}

SCM
quasiquote (SCM x)
{
  return cons (cell_symbol_quasiquote, x);
}

SCM
quasisyntax (SCM x)
{
  return cons (cell_symbol_quasisyntax, x);
}

SCM
pairlis (SCM x, SCM y, SCM a)
{
  if (x == cell_nil)
    return a;
  if (pair_p (x) == cell_f)
    return cons (cons (x, y), a);
  return cons (cons (car (x), car (y)),
               pairlis (cdr (x), cdr (y), a));
}

SCM
assq (SCM x, SCM a)
{
  while (a != cell_nil && eq_p (x, CAAR (a)) == cell_f)
    {
      if (TYPE (a) == BROKEN_HEART || TYPE (CAR (a)) == BROKEN_HEART)
        fprintf (stderr, "oops, broken heart\n");
      a = CDR (a);
    }
  return a != cell_nil ? car (a) : cell_f;
}

#define ENV_CACHE 1
#define CACHE_SIZE 30
#define ENV_HEAD 15

#if !ENV_CACHE
SCM
assq_ref_cache (SCM x, SCM a)
{
  x = assq (x, a);
  if (x == cell_f) return cell_undefined;
  return cdr (x);
}
SCM cache_invalidate (SCM x){}
SCM cache_invalidate_range (SCM p,SCM a){}
SCM cache_save (SCM p){}
SCM cache_lookup (SCM x){}

#else // ENV_CACHE

SCM env_cache_cars[CACHE_SIZE];
SCM env_cache_cdrs[CACHE_SIZE];
int cache_threshold = 0;
SCM
cache_save (SCM p)
{
  int n = g_cells[car (p)].hits;
  if (n < cache_threshold) return cell_unspecified;
  int j = -1;
  for (int i=0; i < CACHE_SIZE; i++) {
    if (!env_cache_cars[i]) {
      j = i;
      break;
    }
    if (env_cache_cars[i] == car (p)) return cell_unspecified;
    if (n > g_cells[env_cache_cars[i]].hits) {
      n = g_cells[env_cache_cars[i]].hits;
      j = i;
    }
  }
  if (j >= 0) {
    cache_threshold = g_cells[car (p)].hits;
    env_cache_cars[j] = car (p);
    env_cache_cdrs[j] = cdr (p);
  }
  return cell_unspecified;
}

SCM
cache_lookup (SCM x)
{
  for (int i=0; i < CACHE_SIZE; i++) {
    if (!env_cache_cars[i]) break;
    if (env_cache_cars[i] == x) return env_cache_cdrs[i];
  }
  return cell_undefined;
}

SCM
cache_invalidate (SCM x)
{
  for (int i=0; i < CACHE_SIZE; i++) {
    if (env_cache_cars[i] == x) {
      env_cache_cars[i] = 0;
      break;
    }
  }
  return cell_unspecified;
}

SCM
cache_invalidate_range (SCM p, SCM a)
{
  do {
    cache_invalidate (caar (p));
    p = cdr (p);
  } while (p != a);
  return cell_unspecified;
}

SCM
assq_ref_cache (SCM x, SCM a)
{
  g_cells[x].hits++;
  SCM c = cache_lookup (x);
  if (c != cell_undefined) return c;
  int i = 0;
  while (a != cell_nil && x != CAAR (a)) {i++;a = cdr (a);}
  if (a == cell_nil) return cell_undefined;
  if (i>ENV_HEAD) cache_save (car (a));
  return cdar (a);
}
#endif // ENV_CACHE

SCM
assert_defined (SCM x, SCM e)
{
  if (e == cell_undefined)
    {
      fprintf (stderr, "eval: unbound variable:");
      display_ (stderr, x);
      fprintf (stderr, "\n");
      assert (!"unbound variable");
    }
  return e;
}

SCM
gc_frame (SCM stack)
{
  SCM frame = car (stack);
  r1 = car (frame);
  r2 = cadr (frame);
  r3 = caddr (frame);
  r0 = cadddr (frame);
  return frame;
}

SCM
gc_stack (SCM a)
{
  SCM frame = cons (r1, cons (r2, cons (r3, cons (r0, cell_nil))));
  stack = cons (frame, stack);
  stack = gc (stack);
  gc_frame (stack);
  stack = cdr (stack);
  return stack;
}

SCM
vm_call (function0_t f, SCM p1, SCM p2, SCM a)
{
  SCM frame = cons (r1, cons (r2, cons (r3, cons (r0, cell_nil))));
  stack = cons (frame, stack);
  r1 = p1;
  r2 = p2;
  r0 = a;
  if (f == vm_if_env && g_free.value + GC_SAFETY > ARENA_SIZE)
    {
      cache_invalidate_range (r0, cell_nil);
      gc_stack (stack);
      frame = car (stack);
    }

  SCM r = f ();
  frame = gc_frame (stack);
  stack = cdr (stack);
  return r;
}

SCM
evlis_env (SCM m, SCM a)
{
  return vm_call (vm_evlis_env, m, cell_undefined, a);
}

SCM
apply_env (SCM fn, SCM x, SCM a)
{
  return vm_call (vm_apply_env, fn, x, a);
}

SCM
eval_env (SCM e, SCM a)
{
  return vm_call (vm_eval_env, e, cell_undefined, a);
}

SCM
expand_macro_env (SCM e, SCM a)
{
  return vm_call (vm_expand_macro_env, e, cell_undefined, a);
}

SCM
begin_env (SCM e, SCM a)
{
  return vm_call (vm_begin_env, e, cell_undefined, a);
}

SCM
if_env (SCM e, SCM a)
{
  return vm_call (vm_if_env, e, cell_undefined, a);
}

SCM
call_lambda (SCM e, SCM x, SCM aa, SCM a) ///((internal))
{
  SCM cl = cons (cons (cell_closure, x), x);
  r1 = e;
  r0 = cl;
  r2 = a;
  r3 = aa;
  cache_invalidate_range (r0, CDR (r3));
  SCM r = vm_call_lambda ();
  cache_invalidate_range (r0, CDR (r3));
  return r;
}

SCM
vm_evlis_env ()
{
  if (r1 == cell_nil) return cell_nil;
  if (TYPE (r1) != PAIR) return eval_env (r1, r0);
  r2 = eval_env (car (r1), r0);
  r1 = evlis_env (cdr (r1), r0);
  return cons (r2, r1);
}

SCM
vm_call_lambda ()
{
  return vm_call (vm_begin_env, r1, cell_undefined, r0);
}

SCM
vm_apply_env ()
{
  if (TYPE (r1) != PAIR)
    {
      if (TYPE (r1) == FUNCTION) return call (r1, r2);
      if (r1 == cell_symbol_call_with_values)
        return call_with_values_env (car (r2), cadr (r2), r0);
      if (r1 == cell_symbol_current_module) return r0;
    }
  else if (car (r1) == cell_symbol_lambda) {
    SCM args = cadr (r1);
    SCM body = cddr (r1);
    SCM p = pairlis (args, r2, r0);
    return call_lambda (body, p, p, r0);
    // r2 = p;
    // cache_invalidate_range (r2, g_cells[r0].cdr);
    // SCM r = begin_env (cddr (r1), cons (cons (cell_closure, p), p));
    // cache_invalidate_range (r2, g_cells[r0].cdr);
    // return r;
  }
  else if (car (r1) == cell_closure) {
    SCM args = caddr (r1);
    SCM body = cdddr (r1);
    SCM aa = cdadr (r1);
    aa = cdr (aa);
    SCM p = pairlis (args, r2, aa);
    return call_lambda (body, p, aa, r0);
    // r2 = p;
    // r3 = aa;
    // cache_invalidate_range (r2, g_cells[r3].cdr);
    // SCM r = begin_env (body, cons (cons (cell_closure, p), p));
    // cache_invalidate_range (r2, g_cells[r3].cdr);
    // return r;
  }
#if BOOT
  else if (car (r1) == cell_symbol_label)
    return apply_env (caddr (r1), r2, cons (cons (cadr (r1), caddr (r1)), r0));
#endif
  SCM e = eval_env (r1, r0);
  char const* type = 0;
  if (e == cell_f || e == cell_t) type = "bool";
  if (TYPE (e) == CHAR) type = "char";
  if (TYPE (e) == NUMBER) type = "number";
  if (TYPE (e) == STRING) type = "string";
  if (e == cell_unspecified) type = "*unspecified*";
  if (e == cell_undefined) type =  "*undefined*";
  if (type)
    {
      fprintf (stderr, "cannot apply: %s: ", type);
      display_ (stderr, e);
      fprintf (stderr, " [");
      display_ (stderr, r1);
      fprintf (stderr, "]\n");
      assert (!"cannot apply");
    }
  return apply_env (e, r2, r0);
}

SCM cstring_to_list (char const* s);

SCM
vm_eval_env ()
{
  switch (TYPE (r1))
    {
    case PAIR:
      {
        if (car (r1) == cell_symbol_quote)
          return cadr (r1);
#if QUASISYNTAX
        if (car (r1) == cell_symbol_syntax)
          return r1;
#endif
        if (car (r1) == cell_symbol_begin)
          return begin_env (r1, r0);
        if (car (r1) == cell_symbol_lambda)
          return make_closure (cadr (r1), cddr (r1), assq (cell_closure, r0));
        if (car (r1) == cell_closure)
          return r1;
        if (car (r1) == cell_symbol_if)
          return if_env (cdr (r1), r0);
#if !BOOT
        if (car (r1) == cell_symbol_define)
          return define_env (r1, r0);
        if (car (r1) == cell_symbol_define_macro)
          return define_env (r1, r0);
        if (car (r1) == cell_symbol_primitive_load)
          return load_env (r0);
#else
        if (car (r1) == cell_symbol_define) {
        fprintf (stderr, "C DEFINE: ");
        display_ (stderr,
                  TYPE (cadr (r1)) == SYMBOL
                  ? STRING (cadr (r1))
                  : STRING (caadr (r1)));
        fprintf (stderr, "\n");
      }
      assert (car (r1) != cell_symbol_define);
      assert (car (r1) != cell_symbol_define_macro);
#endif
#if 1 //!BOOT
      if (car (r1) == cell_symbol_set_x)
        return set_env_x (cadr (r1), eval_env (caddr (r1), r0), r0);
#else
      assert (car (r1) != cell_symbol_set_x);
#endif
#if QUASIQUOTE
      if (car (r1) == cell_symbol_unquote)
        return eval_env (cadr (r1), r0);
      if (car (r1) == cell_symbol_quasiquote)
        return eval_quasiquote (cadr (r1), add_unquoters (r0));
#endif //QUASIQUOTE
#if QUASISYNTAX
      if (car (r1) == cell_symbol_unsyntax)
        return eval_env (cadr (r1), r0);
      if (car (r1) == cell_symbol_quasisyntax)
        return eval_quasisyntax (cadr (r1), add_unsyntaxers (r0));
#endif //QUASISYNTAX
      SCM x = expand_macro_env (r1, r0);
      if (x != r1)
          return eval_env (x, r0);
      SCM m = evlis_env (CDR (r1), r0);
      return apply_env (car (r1), m, r0);
      }
    case SYMBOL: return assert_defined (r1, assq_ref_cache (r1, r0));
    default: return r1;
    }
}

SCM
vm_expand_macro_env ()
{
  if (TYPE (CAR (r1)) == STRING && string_to_symbol (CAR (r1)) == cell_symbol_noexpand)
    return cadr (r1);

  SCM macro;
  SCM expanders;
  if (TYPE (r1) == PAIR
      && (macro = lookup_macro (car (r1), r0)) != cell_f)
    return apply_env (macro, CDR (r1), r0);
  else if (TYPE (r1) == PAIR
           && TYPE (CAR (r1)) == SYMBOL
           && ((expanders = assq_ref_cache (cell_symbol_sc_expander_alist, r0)) != cell_undefined)
           && ((macro = assq (CAR (r1), expanders)) != cell_f))
    {
      SCM sc_expand = assq_ref_cache (cell_symbol_expand_macro, r0);
      if (sc_expand != cell_undefined && sc_expand != cell_f)
        r1 = apply_env (sc_expand, cons (r1, cell_nil), r0);
    }
  return r1;
}

SCM
vm_begin_env ()
{
  SCM r = cell_unspecified;
  while (r1 != cell_nil) {
    if (TYPE (r1) == PAIR && TYPE (CAR (r1)) == PAIR && caar (r1) == cell_symbol_begin)
      r1 = append2 (cdar (r1), cdr (r1));
    r = eval_env (car (r1), r0);
    r1 = CDR (r1);
  }
  return r;
}

SCM
vm_if_env ()
{
  SCM x = eval_env (car (r1), r0);
  if (x != cell_f)
    return eval_env (cadr (r1), r0);
  if (cddr (r1) != cell_nil)
    return eval_env (caddr (r1), r0);
  return cell_unspecified;
}

SCM
call (SCM fn, SCM x)
{
  if ((FUNCTION (fn).arity > 0 || FUNCTION (fn).arity == -1)
      && x != cell_nil && TYPE (CAR (x)) == VALUES)
    x = cons (CADAR (x), CDR (x));
  if ((FUNCTION (fn).arity > 1 || FUNCTION (fn).arity == -1)
      && x != cell_nil && TYPE (CDR (x)) == PAIR && TYPE (CADR (x)) == VALUES)
    x = cons (CAR (x), cons (CDADAR (x), CDR (x)));
  switch (FUNCTION (fn).arity)
    {
    case 0: return FUNCTION (fn).function0 ();
    case 1: return FUNCTION (fn).function1 (car (x));
    case 2: return FUNCTION (fn).function2 (car (x), cadr (x));
    case 3: return FUNCTION (fn).function3 (car (x), cadr (x), caddr (x));
    case -1: return FUNCTION (fn).functionn (x);
    }
  return cell_unspecified;
}

SCM
append2 (SCM x, SCM y)
{
  if (x == cell_nil) return y;
  assert (TYPE (x) == PAIR);
  return cons (car (x), append2 (cdr (x), y));
}

SCM
append (SCM x) ///((arity . n))
 {
  if (x == cell_nil) return cell_nil;
  return append2 (car (x), append (cdr (x)));
 }

SCM
make_char (int x)
{
  g_cells[tmp_num].value = CHAR;
  g_cells[tmp_num2].value = x;
  return make_cell (tmp_num, tmp_num2, tmp_num2);
}

SCM
make_function (SCM name, SCM id, SCM arity)
{
  g_cells[tmp_num3].value = FUNCTION;
  // function fun_read_byte = {.function0=&read_byte, .arity=0};
  // scm scm_read_byte = {FUNCTION, .name="read-int", .function=&fun_read_byte};
  // SCM cell_read_byte = 93;
  function *f = (function*)malloc (sizeof (function));
  f->arity = VALUE (arity);
  g_cells[tmp_num4].value = (long)f;
  return make_cell (tmp_num3, name, tmp_num4);
}

SCM
make_macro (SCM name, SCM x)
{
  g_cells[tmp_num].value = MACRO;
  return make_cell (tmp_num, STRING (name), x);
}

SCM
make_number (int x)
{
  g_cells[tmp_num].value = NUMBER;
  g_cells[tmp_num2].value = x;
  return make_cell (tmp_num, tmp_num2, tmp_num2);
}

SCM
make_ref (SCM x)
{
  g_cells[tmp_num].value = REF;
  return make_cell (tmp_num, x, x);
}

SCM
make_string (SCM x)
{
  g_cells[tmp_num].value = STRING;
  return make_cell (tmp_num, x, 0);
}

SCM
cstring_to_list (char const* s)
{
  SCM p = cell_nil;
  int i = strlen (s);
  while (i--)
    p = cons (make_char (s[i]), p);
  return p;
}

SCM
list_of_char_equal_p (SCM a, SCM b)
{
  while (a != cell_nil && b != cell_nil && VALUE (car (a)) == VALUE (car (b))) {
    assert (TYPE (car (a)) == CHAR);
    assert (TYPE (car (b)) == CHAR);
    a = cdr (a);
    b = cdr (b);
  }
  return (a == cell_nil && b == cell_nil) ? cell_t : cell_f;
}

SCM
internal_lookup_symbol (SCM s)
{
  SCM x = symbols;
  while (x) {
    // .string and .name is the same field; .name is used as a handy
    // static field initializer.  A string can only be mistaken for a
    // cell with type == PAIR for the one character long, zero-padded
    // #\etx.
    SCM p = STRING (car (x));
    if (p < 0 || p >= g_free.value || TYPE (p) != PAIR)
      STRING (car (x)) = cstring_to_list (NAME (car (x)));
    if (list_of_char_equal_p (STRING (car (x)), s) == cell_t) break;
    x = cdr (x);
  }
  if (x) x = car (x);
  return x;
}

SCM
internal_make_symbol (SCM s)
{
  g_cells[tmp_num].value = SYMBOL;
  SCM x = make_cell (tmp_num, s, 0);
  symbols = cons (x, symbols);
  return x;
}

SCM
make_symbol (SCM s)
{
  SCM x = internal_lookup_symbol (s);
  return x ? x : internal_make_symbol (s);
}

SCM
make_vector (SCM n)
{
  int k = VALUE (n);
  g_cells[tmp_num].value = VECTOR;
  SCM v = gc_alloc (k);
  SCM x = make_cell (tmp_num, k, v);
  for (int i=0; i<k; i++) g_cells[v+i] = g_cells[vector_entry (cell_unspecified)];
  return x;
}

SCM
values (SCM x) ///((arity . n))
{
  SCM v = cons (0, x);
  TYPE (v) = VALUES;
  return v;
}

SCM
call_with_values_env (SCM producer, SCM consumer, SCM a)
{
  SCM v = apply_env (producer, cell_nil, a);
  if (TYPE (v) == VALUES)
    v = CDR (v);
  return apply_env (consumer, v, a);
}

SCM
vector_length (SCM x)
{
  assert (TYPE (x) == VECTOR);
  return make_number (LENGTH (x));
}

SCM
vector_ref (SCM x, SCM i)
{
  assert (TYPE (x) == VECTOR);
  assert (VALUE (i) < LENGTH (x));
  SCM e = VECTOR (x) + VALUE (i);
  if (TYPE (e) == REF) e = g_cells[e].ref;
  if (TYPE (e) == CHAR) e = make_char (VALUE (e));
  if (TYPE (e) == NUMBER) e = make_number (VALUE (e));
  return e;
}

SCM
vector_entry (SCM x) {
  if (TYPE (x) == PAIR || TYPE (x) == SPECIAL || TYPE (x) == STRING || TYPE (x) == SYMBOL || TYPE (x) == VECTOR) x = make_ref (x);
  return x;
}

SCM
vector_set_x (SCM x, SCM i, SCM e)
{
  assert (TYPE (x) == VECTOR);
  assert (VALUE (i) < LENGTH (x));
  g_cells[VECTOR (x)+g_cells[i].value] = g_cells[vector_entry (e)];
  return cell_unspecified;
}

SCM
lookup (SCM s, SCM a)
{
  if (isdigit (VALUE (car (s))) || (VALUE (car (s)) == '-' && cdr (s) != cell_nil)) {
    SCM p = s;
    int sign = 1;
    if (VALUE (car (s)) == '-') {
      sign = -1;
      p = cdr (s);
    }
    int n = 0;
    while (p != cell_nil && isdigit (VALUE (car (p)))) {
      n *= 10;
      n += VALUE (car (p)) - '0';
      p = cdr (p);
    }
    if (p == cell_nil) return make_number (n * sign);
  }

  SCM x = internal_lookup_symbol (s);
  if (x) return x;

  if (cdr (s) == cell_nil) {
    if (VALUE (car (s)) == '\'') return cell_symbol_quote;
    if (VALUE (car (s)) == '`') return cell_symbol_quasiquote;
    if (VALUE (car (s)) == ',') return cell_symbol_unquote;
  }
  else if (cddr (s) == cell_nil) {
    if (VALUE (car (s)) == ',' && VALUE (cadr (s)) == '@') return cell_symbol_unquote_splicing;
    if (VALUE (car (s)) == '#' && VALUE (cadr (s)) == '\'') return cell_symbol_syntax;
    if (VALUE (car (s)) == '#' && VALUE (cadr (s)) == '`') return cell_symbol_quasisyntax;
    if (VALUE (car (s)) == '#' && VALUE (cadr (s)) == ',') return cell_symbol_unsyntax;
  }
  else if (cdddr (s) == cell_nil) {
    if (VALUE (car (s)) == '#' && VALUE (cadr (s)) == ',' && VALUE (caddr (s)) == '@') return cell_symbol_unsyntax_splicing;
        if (VALUE (car (s)) == 'E' && VALUE (cadr (s)) == 'O' && VALUE (caddr (s)) == 'F') {
      fprintf (stderr, "mes: got EOF\n");
      return cell_nil; // `EOF': eval program, which may read stdin
    }
  }

  return internal_make_symbol (s);
}

SCM
lookup_char (int c, SCM a)
{
  return lookup (cons (make_char (c), cell_nil), a);
}

SCM
list_to_vector (SCM x)
{
  g_cells[tmp_num].value = VALUE (length (x));
  SCM v = make_vector (tmp_num);
  SCM p = VECTOR (v);
  while (x != cell_nil)
    {
      g_cells[p++] = g_cells[vector_entry (car (x))];
      x = cdr (x);
    }
  return v;
}

SCM
force_output (SCM p) ///((arity . n))
{
  int fd = 1;
  if (TYPE (p) == PAIR && TYPE (car (p)) == NUMBER) fd = VALUE (car (p));
  FILE *f = fd == 1 ? stdout : stderr;
  fflush (f);
}

SCM
display_ (FILE* f, SCM x)
{
  return display_helper (f, x, false, "", false);
}

SCM
display (SCM x) ///((arity . n))
{
  SCM e = car (x);
  SCM p = cdr (x);
  int fd = 1;
  if (TYPE (p) == PAIR && TYPE (car (p)) == NUMBER) fd = HITS (car (p));
  FILE *f = fd == 1 ? stdout : stderr;
  return display_helper (f, e, false, "", false);
}

SCM
newline (SCM p) ///((arity . n))
{
  int fd = 1;
  if (TYPE (p) == PAIR && TYPE (car (p)) == NUMBER) fd = VALUE (car (p));
  FILE *f = fd == 1 ? stdout : stderr;
  fputs ("\n", f);
  return cell_unspecified;
}

SCM
display_helper (FILE* f, SCM x, bool cont, char const *sep, bool quote)
{
  SCM r;
  fprintf (f, "%s", sep);
  switch (TYPE (x))
    {
    case CHAR:
      {
        char const *name = 0;
        if (VALUE (x) == char_nul.value) name = char_nul.name;
        else if (VALUE (x) == char_backspace.value) name = char_backspace.name;
        else if (VALUE (x) == char_tab.value) name = char_tab.name;
        else if (VALUE (x) == char_newline.value) name = char_newline.name;
        else if (VALUE (x) == char_vt.value) name = char_vt.name;
        else if (VALUE (x) == char_page.value) name = char_page.name;
        else if (VALUE (x) == char_return.value) name = char_return.name;
        else if (VALUE (x) == char_space.value) name = char_space.name;
        if (name) fprintf (f, "#\\%s", name);
        else fprintf (f, "#\\%c", VALUE (x));
        break;
      }
    case MACRO:
      fprintf (f, "(*macro* ");
      display_helper (f, g_cells[x].macro, cont, sep, quote);
      fprintf (f, ")");
      break;
    case NUMBER: fprintf (f, "%d", VALUE (x)); break;
    case PAIR:
      {
        if (car (x) == cell_circular) {
          fprintf (f, "(*circ* . #-1#)");
          return cell_unspecified;
        }
        if (car (x) == cell_closure) {
          fprintf (f, "(*closure* . #-1#)");
          return cell_unspecified;
        }
        if (car (x) == cell_symbol_quote) {
          fprintf (f, "'");
          return display_helper (f, car (cdr (x)), cont, "", true);
        }
        if (!cont) fprintf (f, "(");
        display_ (f, car (x));
        if (cdr (x) && TYPE (cdr (x)) == PAIR)
          display_helper (f, cdr (x), true, " ", false);
        else if (cdr (x) != cell_nil) {
          fprintf (f, " . ");
          display_ (f, cdr (x));
        }
        if (!cont) fprintf (f, ")");
        break;
      }
    case VECTOR:
      {
        fprintf (f, "#(");
        for (int i = 0; i < LENGTH (x); i++) {
          if (TYPE (VECTOR (x)+i) == VECTOR
              || (TYPE (VECTOR (x)+i) == REF
                  && TYPE (REF (VECTOR (x)+i)) == VECTOR))
            fprintf (f, "%s#(...)", i ? " " : "");
          else
            display_helper (f,VECTOR (x)+i, false, i ? " " : "", false);
        }
        fprintf (f, ")");
        break;
      }
    case REF: display_helper (f, g_cells[x].ref, cont, "", true); break;
    case FUNCTION:
      {
        fprintf (f, "#<procedure ");
        SCM p = STRING (x);
        if (p < 0 || p >= g_free.value || TYPE (p) != PAIR)
          fprintf (f, "%s", NAME (x));
        else
          display_ (f, STRING (x));
        fprintf (f, ">");
        break;
      }
    case BROKEN_HEART: fprintf (f, "<3"); break;
    default:
      if (STRING (x))
        {
          SCM p = STRING (x);
          assert (p);
          while (p != cell_nil) {
            assert (TYPE (car (p)) == CHAR);
            fputc (VALUE (car (p)), f);
            p = cdr (p);
          }
        }
      else if (TYPE (x) != PAIR && NAME (x)) fprintf (f, "%s", NAME (x));
    }
  return cell_unspecified;
}

// READ

FILE *g_stdin;
int
getchar ()
{
  return getc (g_stdin);
}

int
ungetchar (int c)
{
  return ungetc (c, g_stdin);
}

int
peekchar ()
{
  int c = getchar ();
  ungetchar (c);
  return c;
}

SCM
peek_char ()
{
  return make_char (peekchar ());
}

SCM
read_char ()
{
  return make_char (getchar ());
}

SCM
write_char (SCM x) ///((arity . n))
{
  SCM c = car (x);
  SCM p = cdr (x);
  int fd = 1;
  if (TYPE (p) == PAIR && TYPE (car (p)) == NUMBER) fd = VALUE (car (p));
  FILE *f = fd == 1 ? stdout : stderr;
  assert (TYPE (c) == NUMBER || TYPE (c) == CHAR);
  fputc (VALUE (c), f);
  return c;
}

SCM
unget_char (SCM c)
{
  assert (TYPE (c) == NUMBER || TYPE (c) == CHAR);
  ungetchar (VALUE (c));
  return c;
}

SCM
symbol_to_list (SCM x)
{
  assert (TYPE (x) == SYMBOL);
  return STRING (x);
}

int
readcomment (int c)
{
  if (c == '\n') return c;
  return readcomment (getchar ());
}

int
readblock (int c)
{
  if (c == '!' && peekchar () == '#') return getchar ();
  return readblock (getchar ());
}

SCM
readword (int c, SCM w, SCM a)
{
  if (c == EOF && w == cell_nil) return cell_nil;
  if (c == '\n' && w == cell_nil) return readword (getchar (), w, a);
  if (c == '\n' && VALUE (car (w)) == '.' && cdr (w) == cell_nil) return cell_dot;
  if (c == EOF || c == '\n') return lookup (w, a);
  if (c == ' ') return readword ('\n', w, a);
  if (c == '"' && w == cell_nil) return readstring ();
  if (c == '"') {ungetchar (c); return lookup (w, a);}
  if (c == '(' && w == cell_nil) return readlist (a);
  if (c == '(') {ungetchar (c); return lookup (w, a);}
  if (c == ')' && w == cell_nil) {ungetchar (c); return cell_nil;}
  if (c == ')') {ungetchar (c); return lookup (w, a);}
  if (c == ',' && peekchar () == '@') {getchar (); return cons (lookup (STRING (cell_symbol_unquote_splicing), a),
                                                                   cons (readword (getchar (), w, a),
                                                                         cell_nil));}
  if ((c == '\''
       || c == '`'
       || c == ',')
      && w == cell_nil) {return cons (lookup_char (c, a),
                                     cons (readword (getchar (), w, a),
                                           cell_nil));}
  if (c == '#' && peekchar () == ',' && w == cell_nil) {
    getchar ();
    if (peekchar () == '@'){getchar (); return cons (lookup (STRING (cell_symbol_unsyntax_splicing), a),
                                                     cons (readword (getchar (), w, a),
                                                           cell_nil));}
    return cons (lookup (STRING (cell_symbol_unsyntax), a), cons (readword (getchar (), w, a), cell_nil));
  }
  if (c == '#' && (peekchar () == '\'' || peekchar () == '`') && w == cell_nil) {
    c = getchar ();
    return cons (lookup (cons (make_char ('#'), cons (make_char (c), cell_nil)), a),
                 cons (readword (getchar (), w, a), cell_nil));}
  if (c == ';') {readcomment (c); return readword ('\n', w, a);}
  if (c == '#' && peekchar () == 'x') {getchar (); return read_hex ();}
  if (c == '#' && peekchar () == '\\') {getchar (); return read_character ();}
  if (c == '#' && w == cell_nil && peekchar () == '(') {getchar (); return list_to_vector (readlist (a));}
  if (c == '#' && peekchar () == '(') {ungetchar (c); return lookup (w, a);}
  if (c == '#' && peekchar () == '!') {getchar (); readblock (getchar ()); return readword (getchar (), w, a);}
  return readword (getchar (), append2 (w, cons (make_char (c), cell_nil)), a);
}

SCM
read_hex ()
{
  int n = 0;
  int c = peekchar ();
  while ((c >= '0' && c <= '9')
         || (c >= 'A' && c <= 'F')
         || (c >= 'a' && c <= 'f')) {
    n <<= 4;
    if (c >= 'a') n += c - 'a' + 10;
    else if (c >= 'A') n += c - 'A' + 10;
    else n+= c - '0';
    getchar ();
    c = peekchar ();
  }
  return make_number (n);
}

SCM
read_character ()
{
  int c = getchar ();
  if (c >= '0' && c <= '7'
      && peekchar () >= '0' && peekchar () <= '7') {
    c = c - '0';
    while (peekchar () >= '0' && peekchar () <= '7') {
      c <<= 3;
      c += getchar () - '0';
    }
  }
  else if (c >= 'a' && c <= 'z'
      && peekchar () >= 'a' && peekchar () <= 'z') {
    char buf[10];
    char *p = buf;
    *p++ = c;
    while (peekchar () >= 'a' && peekchar () <= 'z') {
      *p++ = getchar ();
    }
    *p = 0;
    if (!strcmp (buf, char_nul.name)) c = char_nul.value;
    else if (!strcmp (buf, char_backspace.name)) c = char_backspace.value;
    else if (!strcmp (buf, char_tab.name)) c = char_tab.value;
    else if (!strcmp (buf, char_newline.name)) c = char_newline.value;
    else if (!strcmp (buf, char_vt.name)) c = char_vt.value;
    else if (!strcmp (buf, char_page.name)) c = char_page.value;
    else if (!strcmp (buf, char_return.name)) c = char_return.value;
    else if (!strcmp (buf, char_space.name)) c = char_space.value;
    else {
      fprintf (stderr, "char not supported: %s\n", buf);
      assert (!"char not supported");
    }
  }
  return make_char (c);
}

SCM
append_char (SCM x, int i)
{
  return append2 (x, cons (make_char (i), cell_nil));
}

SCM
readstring ()
{
  SCM p = cell_nil;
  int c = getchar ();
  while (true) {
    if (c == '"') break;
    if (c == '\\' && peekchar () == '"') p = append_char (p, getchar ());
    else if (c == '\\' && peekchar () == 'n') {getchar (); p = append_char (p, '\n');}
    else if (c == EOF) assert (!"EOF in string");
    else p = append_char (p, c);
    c = getchar ();
  }
  return make_string (p);
}

int
eat_whitespace (int c)
{
  while (c == ' ' || c == '\t' || c == '\n') c = getchar ();
  if (c == ';') return eat_whitespace (readcomment (c));
  if (c == '#' && peekchar () == '!') {getchar (); readblock (getchar ()); return eat_whitespace (getchar ());}
  return c;
}

SCM
readlist (SCM a)
{
  int c = getchar ();
  c = eat_whitespace (c);
  if (c == ')') return cell_nil;
  SCM w = readword (c, cell_nil, a);
  if (w == cell_dot)
    return car (readlist (a));
  return cons (w, readlist (a));
}

SCM
read_env (SCM a)
{
  return readword (getchar (), cell_nil, a);
}

SCM
acons (SCM key, SCM value, SCM alist)
{
  return cons (cons (key, value), alist);
}

SCM
add_environment (SCM a, char const *name, SCM x)
{
  return acons (make_symbol (cstring_to_list (name)), x, a);
}

SCM
mes_environment () ///((internal))
{
  // setup GC
  g_cells = (scm *)malloc (ARENA_SIZE*sizeof(scm));
  g_cells[0].type = VECTOR;
  g_cells[0].length = ARENA_SIZE - 1;
  g_cells[0].length = 10;
  g_cells[0].vector = 0;
  g_cells++;
  // a = add_environment (a, "%free", &g_free); hihi, gets <3 moved
  // a = add_environment (a, "%the-cells", g_cells);
  // a = add_environment (a, "%new-cells", g_news);

//#include "mes.symbols.i"

  g_cells[0].type = CHAR;
  g_cells[0].value = 'c';
  g_free.value = 1; // 0 is tricky

#if !MES_MINI
#include "mes.symbols.i"
#else // MES_MINI
  cell_nil = g_free.value++;
  g_cells[cell_nil] = scm_nil;
  cell_f = g_free.value++;
  g_cells[cell_f] = scm_f;
  cell_t = g_free.value++;
  g_cells[cell_t] = scm_t;
  cell_undefined = g_free.value++;
  g_cells[cell_undefined] = scm_undefined;
  cell_unspecified = g_free.value++;
  g_cells[cell_unspecified] = scm_unspecified;
  cell_closure = g_free.value++;
  g_cells[cell_closure] = scm_closure;
  cell_begin = g_free.value++;
  g_cells[cell_begin] = scm_begin;

  cell_symbol_begin = g_free.value++;
  g_cells[cell_symbol_begin] = scm_symbol_begin;

  cell_symbol_sc_expander_alist = g_free.value++;
  g_cells[cell_symbol_sc_expander_alist] = scm_symbol_sc_expander_alist;
  cell_symbol_sc_expand = g_free.value++;
  g_cells[cell_symbol_sc_expand] = scm_symbol_sc_expand;

  // cell_dot = g_free.value++;
  // g_cells[cell_dot] = scm_dot;
  // cell_circular = g_free.value++;
  // g_cells[cell_circular] = scm_circular;
  // cell_symbol_lambda = g_free.value++;
  // g_cells[cell_symbol_lambda] = scm_symbol_lambda;
  // cell_symbol_if = g_free.value++;
  // g_cells[cell_symbol_if] = scm_symbol_if;
  // cell_symbol_define = g_free.value++;
  // g_cells[cell_symbol_define] = scm_symbol_define;
  // cell_symbol_define_macro = g_free.value++;
  // g_cells[cell_symbol_define_macro] = scm_symbol_define_macro;
  
#endif // MES_MINI
  
  SCM symbol_max = g_free.value;

#if MES_FULL
#include "define.i"
#include "lib.i"
#include "math.i"
#include "mes.i"
#include "posix.i"
#include "quasiquote.i"
#include "string.i"
#include "type.i"
#else

  cell_cons = g_free.value++;
  cell_display = g_free.value++;
  cell_eq_p = g_free.value++;
  cell_newline = g_free.value++;

  g_cells[cell_cons] = scm_cons;
  g_cells[cell_display] = scm_display;
  g_cells[cell_eq_p] = scm_eq_p;
  g_cells[cell_newline] = scm_newline;

  cell_make_vector = g_free.value++;
  g_cells[cell_make_vector] = scm_make_vector;

#endif
  
  tmp = g_free.value++;
  tmp_num = g_free.value++;
  g_cells[tmp_num].type = NUMBER;
  tmp_num2 = g_free.value++;
  g_cells[tmp_num2].type = NUMBER;

  g_start = g_free.value;

  symbols = 0;
  for (int i=1; i<symbol_max; i++)
    symbols = cons (i, symbols);
  
  SCM a = cell_nil;

#if MES_FULL
#include "define.environment.i"
#include "lib.environment.i"
#include "math.environment.i"
#include "mes.environment.i"
#include "posix.environment.i"
  //#include "quasiquote.environment.i"
#include "string.environment.i"
#include "type.environment.i"
#else // !MES_FULL

  a = add_environment (a, "cons", cell_cons);
  a = add_environment (a, "display", cell_display);
  a = add_environment (a, "eq?", cell_eq_p);
  a = add_environment (a, "newline", cell_newline);

  a = add_environment (a, "make-vector", cell_make_vector);

#if !MES_MINI
   a = add_environment (a, "*", cell_multiply);
   a = add_environment (a, "list", cell_list);
   //
   a = add_environment (a, "car", cell_car);
   a = add_environment (a, "cdr", cell_cdr);
   a = add_environment (a, "+", cell_plus);
   a = add_environment (a, "quote", cell_quote);
   a = add_environment (a, "null?", cell_null_p);
   a = add_environment (a, "=", cell_is_p);

   // a = add_environment (a, "gc", cell_gc);
   // a = add_environment (a, "apply-env", cell_apply_env);
   // a = add_environment (a, "eval-env", cell_eval_env);
   // a = add_environment (a, "cadr", cell_cadr);
#endif // !MES_MINI
#endif // !MES_FULL

#if BOOT
  ////symbols = cons (cell_symbol_label, symbols);
  a = cons (cons (cell_symbol_label, cell_t), a);
#endif
  a = cons (cons (cell_symbol_begin, cell_begin), a);

  a = add_environment (a, "sc-expand", cell_f);

  a = cons (cons (cell_closure, a), a);

  internal_lookup_symbol (cell_nil);

  r0 = a;
  r1 = make_char (0);
  r2 = make_char (0);
  r3 = make_char (0);
  stack = cons (cell_nil, cell_nil);

  return a;
}

SCM
make_lambda (SCM args, SCM body)
{
  return cons (cell_symbol_lambda, cons (args, body));
}

SCM
make_closure (SCM args, SCM body, SCM a)
{
  return cons (cell_closure, cons (cons (cell_circular, a), cons (args, body)));
}

SCM
lookup_macro (SCM x, SCM a)
{
  if (TYPE (x) != SYMBOL) return cell_f;
  SCM m = assq_ref_cache (x, a);
  if (macro_p (m) == cell_t) return MACRO (m);
  return cell_f;
}

SCM
read_input_file_env (SCM e, SCM a)
{
  if (e == cell_nil) return e;
  return cons (e, read_input_file_env (read_env (a), a));
}

SCM
load_env (SCM a)
{
  SCM p = read_input_file_env (read_env (a), a);
  return begin_env (p, a);
}

#include "type.c"
#include "define.c"
#include "lib.c"
#include "math.c"
#include "posix.c"
#include "quasiquote.c"
#include "string.c"

int
main (int argc, char *argv[])
{
  if (argc > 1 && !strcmp (argv[1], "--help")) return puts ("Usage: mes < FILE\n");
  if (argc > 1 && !strcmp (argv[1], "--version")) return puts ("Mes 0.2\n");
  g_stdin = stdin;
  SCM a = mes_environment ();
  display_ (stderr, load_env (a));
  fputs ("", stderr);
  fprintf (stderr, "\nstats: [%d]\n", g_free.value);
  return 0;
}