mes/reader.c
Jan Nieuwenhuizen b66cd8627c core: Rewrite eval_apply in continuation passing style.
* mes.c (scm_vm_evlis, scm_vm_evlis2, scm_vm_evlis3, scm_vm_apply,
  scm_vm_apply2, scm_vm_eval, scm_vm_eval_set_x, scm_vm_eval_macro,
  scm_vm_eval2, scm_vm_macro_expand, scm_vm_begin,
  scm_vm_begin_read_input_file, scm_vm_begin2, scm_vm_if,
  scm_vm_if_expr, scm_vm_call_with_values, scm_vm_call_with_values2,
  scm_vm_return): New specials.
  (scm_vm_eval_car, scm_vm_eval_cdr, scm_vm_eval_cons,
  scm_vm_eval_null_p)[PRIMITIVE-EVAL]: New specials.
  (eval_apply_t, g_target): Remove.
  (push_cc): New function.
  (eval_apply): Rewrite.
  (vm_call, eval_env, apply_env, eval_env, macro_expand_env, begin_env,
  call_with_values_env): Remove.
* posix.c (stderr_): Update.
* reader.c (read_input_file_env): Update.
* module/mes/base-0.mes: Update.
2016-12-28 21:55:42 +01:00

135 lines
3.5 KiB
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/>.
*/
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
read_input_file_env (SCM a)
{
r0 = a;
if (assq_ref_cache (cell_symbol_read_input_file, r0) != cell_undefined)
return apply (cell_symbol_read_input_file, cell_nil, r0);
return read_input_file_env_ (read_env (r0), r0);
}
int
read_line_comment (int c)
{
if (c == '\n') return c;
return read_line_comment (getchar ());
}
SCM
read_word (int c, SCM w, SCM a)
{
if (c == EOF && w == cell_nil) return cell_nil;
if (c == '\t') return read_word ('\n', w, a);
if (c == '\f') return read_word ('\n', w, a);
if (c == '\n' && w == cell_nil) return read_word (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 read_word ('\n', w, a);
if (c == '(' && w == cell_nil) return read_list (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 == ';') {read_line_comment (c); return read_word ('\n', w, a);}
return read_word (getchar (), append2 (w, cons (MAKE_CHAR (c), cell_nil)), a);
}
int
eat_whitespace (int c)
{
while (c == ' ' || c == '\t' || c == '\n' || c == '\f') c = getchar ();
if (c == ';') return eat_whitespace (read_line_comment (c));
return c;
}
SCM
read_list (SCM a)
{
int c = getchar ();
c = eat_whitespace (c);
if (c == ')') return cell_nil;
SCM w = read_word (c, cell_nil, a);
if (w == cell_dot)
return car (read_list (a));
return cons (w, read_list (a));
}
SCM
read_env (SCM a)
{
return read_word (getchar (), cell_nil, a);
}
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 = lookup_symbol_ (s);
return x ? x : make_symbol_ (s);
}
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
lookup_symbol_ (SCM s)
{
SCM x = g_symbols;
while (x) {
if (list_of_char_equal_p (STRING (car (x)), s) == cell_t) break;
x = cdr (x);
}
if (x) x = car (x);
return x;
}