picrin/extlib/benz/macro.c

352 lines
8.0 KiB
C

/**
* See Copyright Notice in picrin.h
*/
#include "picrin.h"
#include "picrin/object.h"
KHASH_DEFINE(env, pic_id *, pic_sym *, kh_ptr_hash_func, kh_ptr_hash_equal)
pic_value
pic_make_env(pic_state *pic, pic_value up)
{
struct pic_env *env;
env = (struct pic_env *)pic_obj_alloc(pic, sizeof(struct pic_env), PIC_TYPE_ENV);
env->up = pic_env_ptr(pic, up);
env->lib = NULL;
kh_init(env, &env->map);
return pic_obj_value(env);
}
pic_value
pic_add_identifier(pic_state *pic, pic_value id, pic_value env)
{
const char *name;
pic_value uid, str;
name = pic_str(pic, pic_id_name(pic, id));
if (pic_env_ptr(pic, env)->up == NULL && pic_sym_p(pic, id)) { /* toplevel & public */
str = pic_strf_value(pic, "~a/%s", pic_obj_value(pic_env_ptr(pic, env)->lib), name);
} else {
str = pic_strf_value(pic, ".%s.%d", name, pic->ucnt++);
}
uid = pic_intern(pic, str);
return pic_put_identifier(pic, id, uid, env);
}
pic_value
pic_put_identifier(pic_state *pic, pic_value id, pic_value uid, pic_value env)
{
khiter_t it;
int ret;
it = kh_put(env, &pic_env_ptr(pic, env)->map, pic_id_ptr(pic, id), &ret);
kh_val(&pic_env_ptr(pic, env)->map, it) = pic_sym_ptr(pic, uid);
return uid;
}
static bool
search_scope(pic_state *pic, pic_value id, pic_value env, pic_value *uid)
{
khiter_t it;
it = kh_get(env, &pic_env_ptr(pic, env)->map, pic_id_ptr(pic, id));
if (it == kh_end(&pic_env_ptr(pic, env)->map)) {
return false;
}
*uid = pic_obj_value(kh_val(&pic_env_ptr(pic, env)->map, it));
return true;
}
static bool
search(pic_state *pic, pic_value id, pic_value env, pic_value *uid)
{
struct pic_env *e;
while (1) {
if (search_scope(pic, id, env, uid))
return true;
e = pic_env_ptr(pic, env)->up;
if (e == NULL)
break;
env = pic_obj_value(e);
}
return false;
}
pic_value
pic_find_identifier(pic_state *pic, pic_value id, pic_value env)
{
struct pic_env *e;
pic_value uid;
while (! search(pic, id, env, &uid)) {
if (pic_sym_p(pic, id)) {
while (1) {
e = pic_env_ptr(pic, env);
if (e->up == NULL)
break;
env = pic_obj_value(e->up);
}
return pic_add_identifier(pic, id, env);
}
env = pic_obj_value(pic_id_ptr(pic, id)->env); /* do not overwrite id first */
id = pic_obj_value(pic_id_ptr(pic, id)->u.id);
}
return uid;
}
/**
* macro expander
*/
static void
define_macro(pic_state *pic, pic_value uid, pic_value mac)
{
if (pic_weak_has(pic, pic->macros, uid)) {
pic_warnf(pic, "redefining syntax variable: ~s", uid);
}
pic_weak_set(pic, pic->macros, uid, mac);
}
static bool
find_macro(pic_state *pic, pic_value uid, pic_value *mac)
{
if (! pic_weak_has(pic, pic->macros, uid)) {
return false;
}
*mac = pic_weak_ref(pic, pic->macros, uid);
return true;
}
static void
shadow_macro(pic_state *pic, pic_value uid)
{
if (pic_weak_has(pic, pic->macros, uid)) {
pic_weak_del(pic, pic->macros, uid);
}
}
static pic_value expand(pic_state *, pic_value expr, pic_value env, pic_value deferred);
static pic_value expand_lambda(pic_state *, pic_value expr, pic_value env);
static pic_value
expand_var(pic_state *pic, pic_value id, pic_value env, pic_value deferred)
{
pic_value mac, functor;
functor = pic_find_identifier(pic, id, env);
if (find_macro(pic, functor, &mac)) {
return expand(pic, pic_call(pic, mac, 2, id, env), env, deferred);
}
return functor;
}
static pic_value
expand_quote(pic_state *pic, pic_value expr)
{
return pic_cons(pic, pic->sQUOTE, pic_cdr(pic, expr));
}
static pic_value
expand_list(pic_state *pic, pic_value obj, pic_value env, pic_value deferred)
{
size_t ai = pic_enter(pic);
pic_value x, head, tail;
if (pic_pair_p(pic, obj)) {
head = expand(pic, pic_car(pic, obj), env, deferred);
tail = expand_list(pic, pic_cdr(pic, obj), env, deferred);
x = pic_cons(pic, head, tail);
} else {
x = expand(pic, obj, env, deferred);
}
pic_leave(pic, ai);
pic_protect(pic, x);
return x;
}
static pic_value
expand_defer(pic_state *pic, pic_value expr, pic_value deferred)
{
pic_value skel = pic_cons(pic, pic_invalid_value(pic), pic_invalid_value(pic));
pic_set_car(pic, deferred, pic_cons(pic, pic_cons(pic, expr, skel), pic_car(pic, deferred)));
return skel;
}
static void
expand_deferred(pic_state *pic, pic_value deferred, pic_value env)
{
pic_value defer, val, src, dst, it;
deferred = pic_car(pic, deferred);
pic_for_each (defer, pic_reverse(pic, deferred), it) {
src = pic_car(pic, defer);
dst = pic_cdr(pic, defer);
val = expand_lambda(pic, src, env);
/* copy */
pic_set_car(pic, dst, pic_car(pic, val));
pic_set_cdr(pic, dst, pic_cdr(pic, val));
}
}
static pic_value
expand_lambda(pic_state *pic, pic_value expr, pic_value env)
{
pic_value formal, body;
pic_value in;
pic_value a, deferred;
in = pic_make_env(pic, env);
for (a = pic_cadr(pic, expr); pic_pair_p(pic, a); a = pic_cdr(pic, a)) {
pic_add_identifier(pic, pic_car(pic, a), in);
}
if (pic_id_p(pic, a)) {
pic_add_identifier(pic, a, in);
}
deferred = pic_list(pic, 1, pic_nil_value(pic));
formal = expand_list(pic, pic_list_ref(pic, expr, 1), in, deferred);
body = expand(pic, pic_list_ref(pic, expr, 2), in, deferred);
expand_deferred(pic, deferred, in);
return pic_list(pic, 3, pic->sLAMBDA, formal, body);
}
static pic_value
expand_define(pic_state *pic, pic_value expr, pic_value env, pic_value deferred)
{
pic_value id, uid, val;
id = pic_cadr(pic, expr);
if (! search_scope(pic, id, env, &uid)) {
uid = pic_add_identifier(pic, id, env);
} else {
shadow_macro(pic, uid);
}
val = expand(pic, pic_list_ref(pic, expr, 2), env, deferred);
return pic_list(pic, 3, pic->sDEFINE, uid, val);
}
static pic_value
expand_defmacro(pic_state *pic, pic_value expr, pic_value env)
{
pic_value pic_compile(pic_state *, pic_value);
pic_value id, uid, val;
id = pic_cadr(pic, expr);
if (! search_scope(pic, id, env, &uid)) {
uid = pic_add_identifier(pic, id, env);
}
val = pic_call(pic, pic_compile(pic, pic_expand(pic, pic_list_ref(pic, expr, 2), env)), 0);
if (! pic_proc_p(pic, val)) {
pic_errorf(pic, "macro definition \"~s\" evaluates to non-procedure object", id);
}
define_macro(pic, uid, val);
return pic_undef_value(pic);
}
static pic_value
expand_node(pic_state *pic, pic_value expr, pic_value env, pic_value deferred)
{
switch (pic_type(pic, expr)) {
case PIC_TYPE_ID:
case PIC_TYPE_SYMBOL: {
return expand_var(pic, expr, env, deferred);
}
case PIC_TYPE_PAIR: {
pic_value mac;
if (! pic_list_p(pic, expr)) {
pic_errorf(pic, "cannot expand improper list: ~s", expr);
}
if (pic_id_p(pic, pic_car(pic, expr))) {
pic_value functor;
functor = pic_find_identifier(pic, pic_car(pic, expr), env);
if (pic_eq_p(pic, functor, pic->sDEFINE_MACRO)) {
return expand_defmacro(pic, expr, env);
}
else if (pic_eq_p(pic, functor, pic->sLAMBDA)) {
return expand_defer(pic, expr, deferred);
}
else if (pic_eq_p(pic, functor, pic->sDEFINE)) {
return expand_define(pic, expr, env, deferred);
}
else if (pic_eq_p(pic, functor, pic->sQUOTE)) {
return expand_quote(pic, expr);
}
if (find_macro(pic, functor, &mac)) {
return expand(pic, pic_call(pic, mac, 2, expr, env), env, deferred);
}
}
return expand_list(pic, expr, env, deferred);
}
default:
return expr;
}
}
static pic_value
expand(pic_state *pic, pic_value expr, pic_value env, pic_value deferred)
{
size_t ai = pic_enter(pic);
pic_value v;
v = expand_node(pic, expr, env, deferred);
pic_leave(pic, ai);
pic_protect(pic, v);
return v;
}
pic_value
pic_expand(pic_state *pic, pic_value expr, pic_value env)
{
pic_value v, deferred;
#if DEBUG
puts("before expand:");
pic_debug(pic, expr);
puts("");
#endif
deferred = pic_list(pic, 1, pic_nil_value(pic));
v = expand(pic, expr, env, deferred);
expand_deferred(pic, deferred, env);
#if DEBUG
puts("after expand:");
pic_debug(pic, v);
puts("");
#endif
return v;
}