picrin/extlib/benz/macro.c

510 lines
12 KiB
C

/**
* See Copyright Notice in picrin.h
*/
#include "picrin.h"
pic_sym *
pic_add_rename(pic_state *pic, struct pic_env *env, pic_sym *sym)
{
pic_sym *rename;
rename = pic_gensym(pic, sym);
pic_put_rename(pic, env, sym, rename);
return rename;
}
void
pic_put_rename(pic_state *pic, struct pic_env *env, pic_sym *sym, pic_sym *rename)
{
pic_dict_set(pic, env->map, sym, pic_obj_value(rename));
}
bool
pic_find_rename(pic_state *pic, struct pic_env *env, pic_sym *sym, pic_sym **rename)
{
if (! pic_dict_has(pic, env->map, sym)) {
return false;
}
if (rename != NULL) {
*rename = pic_sym_ptr(pic_dict_ref(pic, env->map, sym));
}
return true;
}
static void
define_macro(pic_state *pic, pic_sym *rename, struct pic_proc *mac)
{
pic_dict_set(pic, pic->macros, rename, pic_obj_value(mac));
}
static struct pic_proc *
find_macro(pic_state *pic, pic_sym *rename)
{
if (! pic_dict_has(pic, pic->macros, rename)) {
return NULL;
}
return pic_proc_ptr(pic_dict_ref(pic, pic->macros, rename));
}
static pic_sym *
make_identifier(pic_state *pic, pic_sym *sym, struct pic_env *env)
{
pic_sym *rename;
while (true) {
if (pic_find_rename(pic, env, sym, &rename)) {
return rename;
}
if (! env->up)
break;
env = env->up;
}
if (! pic_interned_p(pic, sym)) {
return sym;
}
else {
return pic_gensym(pic, sym);
}
}
static pic_value macroexpand(pic_state *, pic_value, struct pic_env *);
static pic_value macroexpand_lambda(pic_state *, pic_value, struct pic_env *);
static pic_value
macroexpand_symbol(pic_state *pic, pic_sym *sym, struct pic_env *env)
{
return pic_obj_value(make_identifier(pic, sym, env));
}
static pic_value
macroexpand_quote(pic_state *pic, pic_value expr)
{
return pic_cons(pic, pic_obj_value(pic->rQUOTE), pic_cdr(pic, expr));
}
static pic_value
macroexpand_list(pic_state *pic, pic_value obj, struct pic_env *env)
{
size_t ai = pic_gc_arena_preserve(pic);
pic_value x, head, tail;
if (pic_pair_p(obj)) {
head = macroexpand(pic, pic_car(pic, obj), env);
tail = macroexpand_list(pic, pic_cdr(pic, obj), env);
x = pic_cons(pic, head, tail);
} else {
x = macroexpand(pic, obj, env);
}
pic_gc_arena_restore(pic, ai);
pic_gc_protect(pic, x);
return x;
}
static pic_value
macroexpand_defer(pic_state *pic, pic_value expr, struct pic_env *env)
{
pic_value skel = pic_list1(pic, pic_invalid_value()); /* (#<invalid>) */
pic_push(pic, pic_cons(pic, expr, skel), env->defer);
return skel;
}
static void
macroexpand_deferred(pic_state *pic, struct pic_env *env)
{
pic_value defer, val, src, dst, it;
pic_for_each (defer, pic_reverse(pic, env->defer), it) {
src = pic_car(pic, defer);
dst = pic_cdr(pic, defer);
val = macroexpand_lambda(pic, src, env);
/* copy */
pic_pair_ptr(dst)->car = pic_car(pic, val);
pic_pair_ptr(dst)->cdr = pic_cdr(pic, val);
}
env->defer = pic_nil_value();
}
static pic_value
macroexpand_lambda(pic_state *pic, pic_value expr, struct pic_env *env)
{
pic_value formal, body;
struct pic_env *in;
pic_value a;
if (pic_length(pic, expr) < 2) {
pic_errorf(pic, "syntax error");
}
in = pic_make_env(pic, env);
for (a = pic_cadr(pic, expr); pic_pair_p(a); a = pic_cdr(pic, a)) {
pic_value v = pic_car(pic, a);
if (! pic_sym_p(v)) {
pic_errorf(pic, "syntax error");
}
pic_add_rename(pic, in, pic_sym_ptr(v));
}
if (pic_sym_p(a)) {
pic_add_rename(pic, in, pic_sym_ptr(a));
}
else if (! pic_nil_p(a)) {
pic_errorf(pic, "syntax error");
}
formal = macroexpand_list(pic, pic_cadr(pic, expr), in);
body = macroexpand_list(pic, pic_cddr(pic, expr), in);
macroexpand_deferred(pic, in);
return pic_cons(pic, pic_obj_value(pic->rLAMBDA), pic_cons(pic, formal, body));
}
static pic_value
macroexpand_define(pic_state *pic, pic_value expr, struct pic_env *env)
{
pic_sym *sym, *rename;
pic_value var, val;
while (pic_length(pic, expr) >= 2 && pic_pair_p(pic_cadr(pic, expr))) {
var = pic_car(pic, pic_cadr(pic, expr));
val = pic_cdr(pic, pic_cadr(pic, expr));
expr = pic_list3(pic, pic_obj_value(pic->rDEFINE), var, pic_cons(pic, pic_obj_value(pic->rLAMBDA), pic_cons(pic, val, pic_cddr(pic, expr))));
}
if (pic_length(pic, expr) != 3) {
pic_errorf(pic, "syntax error");
}
var = pic_cadr(pic, expr);
if (! pic_sym_p(var)) {
pic_errorf(pic, "binding to non-symbol object");
}
sym = pic_sym_ptr(var);
if (! pic_find_rename(pic, env, sym, &rename)) {
rename = pic_add_rename(pic, env, sym);
}
val = macroexpand(pic, pic_list_ref(pic, expr, 2), env);
return pic_list3(pic, pic_obj_value(pic->rDEFINE), pic_obj_value(rename), val);
}
static pic_value
macroexpand_defsyntax(pic_state *pic, pic_value expr, struct pic_env *env)
{
pic_value var, val;
pic_sym *sym, *rename;
if (pic_length(pic, expr) != 3) {
pic_errorf(pic, "syntax error");
}
var = pic_cadr(pic, expr);
if (! pic_sym_p(var)) {
pic_errorf(pic, "binding to non-symbol object");
}
sym = pic_sym_ptr(var);
if (! pic_find_rename(pic, env, sym, &rename)) {
rename = pic_add_rename(pic, env, sym);
} else {
pic_warnf(pic, "redefining syntax variable: ~s", pic_obj_value(sym));
}
val = pic_cadr(pic, pic_cdr(pic, expr));
pic_try {
val = pic_eval(pic, val, pic->lib);
} pic_catch {
pic_errorf(pic, "macroexpand error while definition: %s", pic_errmsg(pic));
}
if (! pic_proc_p(val)) {
pic_errorf(pic, "macro definition \"~s\" evaluates to non-procedure object", var);
}
val = pic_apply1(pic, pic_proc_ptr(val), pic_obj_value(env));
if (! pic_proc_p(val)) {
pic_errorf(pic, "macro definition \"~s\" evaluates to non-procedure object", var);
}
define_macro(pic, rename, pic_proc_ptr(val));
return pic_undef_value();
}
static pic_value
macroexpand_macro(pic_state *pic, struct pic_proc *mac, pic_value expr, struct pic_env *env)
{
pic_value v, args;
#if DEBUG
puts("before expand-1:");
pic_debug(pic, expr);
puts("");
#endif
args = pic_list2(pic, expr, pic_obj_value(env));
pic_try {
v = pic_apply(pic, mac, args);
} pic_catch {
pic_errorf(pic, "macroexpand error while application: %s", pic_errmsg(pic));
}
#if DEBUG
puts("after expand-1:");
pic_debug(pic, v);
puts("");
#endif
return v;
}
static pic_value
macroexpand_node(pic_state *pic, pic_value expr, struct pic_env *env)
{
switch (pic_type(expr)) {
case PIC_TT_SYMBOL: {
return macroexpand_symbol(pic, pic_sym_ptr(expr), env);
}
case PIC_TT_PAIR: {
pic_value car;
struct pic_proc *mac;
if (! pic_list_p(expr)) {
pic_errorf(pic, "cannot macroexpand improper list: ~s", expr);
}
car = macroexpand(pic, pic_car(pic, expr), env);
if (pic_sym_p(car)) {
pic_sym *tag = pic_sym_ptr(car);
if (tag == pic->rDEFINE_SYNTAX) {
return macroexpand_defsyntax(pic, expr, env);
}
else if (tag == pic->rLAMBDA) {
return macroexpand_defer(pic, expr, env);
}
else if (tag == pic->rDEFINE) {
return macroexpand_define(pic, expr, env);
}
else if (tag == pic->rQUOTE) {
return macroexpand_quote(pic, expr);
}
if ((mac = find_macro(pic, tag)) != NULL) {
return macroexpand_node(pic, macroexpand_macro(pic, mac, expr, env), env);
}
}
return pic_cons(pic, car, macroexpand_list(pic, pic_cdr(pic, expr), env));
}
default:
return expr;
}
}
static pic_value
macroexpand(pic_state *pic, pic_value expr, struct pic_env *env)
{
size_t ai = pic_gc_arena_preserve(pic);
pic_value v;
#if DEBUG
printf("[macroexpand] expanding... ");
pic_debug(pic, expr);
puts("");
#endif
v = macroexpand_node(pic, expr, env);
pic_gc_arena_restore(pic, ai);
pic_gc_protect(pic, v);
return v;
}
pic_value
pic_macroexpand(pic_state *pic, pic_value expr, struct pic_lib *lib)
{
struct pic_lib *prev;
pic_value v;
#if DEBUG
puts("before expand:");
pic_debug(pic, expr);
puts("");
#endif
/* change library for macro-expansion time processing */
prev = pic->lib;
pic->lib = lib;
lib->env->defer = pic_nil_value(); /* the last expansion could fail and leave defer field old */
v = macroexpand(pic, expr, lib->env);
macroexpand_deferred(pic, lib->env);
pic->lib = prev;
#if DEBUG
puts("after expand:");
pic_debug(pic, v);
puts("");
#endif
return v;
}
struct pic_env *
pic_make_env(pic_state *pic, struct pic_env *up)
{
struct pic_env *env;
struct pic_dict *map;
map = pic_make_dict(pic);
env = (struct pic_env *)pic_obj_alloc(pic, sizeof(struct pic_env), PIC_TT_ENV);
env->up = up;
env->defer = pic_nil_value();
env->map = map;
return env;
}
struct pic_env *
pic_null_syntactic_environment(pic_state *pic)
{
struct pic_env *env;
env = pic_make_env(pic, NULL);
pic_define_syntactic_keyword(pic, env, pic->sDEFINE_LIBRARY, pic->rDEFINE_LIBRARY);
pic_define_syntactic_keyword(pic, env, pic->sIMPORT, pic->rIMPORT);
pic_define_syntactic_keyword(pic, env, pic->sEXPORT, pic->rEXPORT);
pic_define_syntactic_keyword(pic, env, pic->sIN_LIBRARY, pic->rIN_LIBRARY);
pic_define_syntactic_keyword(pic, env, pic->sCOND_EXPAND, pic->rCOND_EXPAND);
return env;
}
void
pic_define_syntactic_keyword(pic_state *pic, struct pic_env *env, pic_sym *sym, pic_sym *rsym)
{
pic_put_rename(pic, env, sym, rsym);
if (pic->lib && pic->lib->env == env) {
pic_export(pic, sym);
}
}
static pic_value
defmacro_call(pic_state *pic)
{
struct pic_proc *self = pic_get_proc(pic);
pic_value args, tmp, proc;
pic_get_args(pic, "oo", &args, &tmp);
proc = pic_attr_ref(pic, pic_obj_value(self), "@@transformer");
return pic_apply_trampoline(pic, pic_proc_ptr(proc), pic_cdr(pic, args));
}
void
pic_defmacro(pic_state *pic, pic_sym *name, pic_sym *id, pic_func_t func)
{
struct pic_proc *proc, *trans;
trans = pic_make_proc(pic, func, pic_symbol_name(pic, name));
pic_put_rename(pic, pic->lib->env, name, id);
proc = pic_make_proc(pic, defmacro_call, "defmacro_call");
pic_attr_set(pic, pic_obj_value(proc), "@@transformer", pic_obj_value(trans));
/* symbol registration */
define_macro(pic, id, proc);
/* auto export! */
pic_export(pic, name);
}
bool
pic_identifier_p(pic_state *pic, pic_value obj)
{
return pic_sym_p(obj) && ! pic_interned_p(pic, pic_sym_ptr(obj));
}
bool
pic_identifier_eq_p(pic_state *pic, struct pic_env *env1, pic_sym *sym1, struct pic_env *env2, pic_sym *sym2)
{
pic_sym *a, *b;
a = make_identifier(pic, sym1, env1);
if (a != make_identifier(pic, sym1, env1)) {
a = sym1;
}
b = make_identifier(pic, sym2, env2);
if (b != make_identifier(pic, sym2, env2)) {
b = sym2;
}
return pic_eq_p(pic_obj_value(a), pic_obj_value(b));
}
static pic_value
pic_macro_identifier_p(pic_state *pic)
{
pic_value obj;
pic_get_args(pic, "o", &obj);
return pic_bool_value(pic_identifier_p(pic, obj));
}
static pic_value
pic_macro_make_identifier(pic_state *pic)
{
pic_value obj;
pic_sym *sym;
pic_get_args(pic, "mo", &sym, &obj);
pic_assert_type(pic, obj, env);
return pic_obj_value(make_identifier(pic, sym, pic_env_ptr(obj)));
}
static pic_value
pic_macro_identifier_eq_p(pic_state *pic)
{
pic_sym *sym1, *sym2;
pic_value env1, env2;
pic_get_args(pic, "omom", &env1, &sym1, &env2, &sym2);
pic_assert_type(pic, env1, env);
pic_assert_type(pic, env2, env);
return pic_bool_value(pic_identifier_eq_p(pic, pic_env_ptr(env1), sym1, pic_env_ptr(env2), sym2));
}
void
pic_init_macro(pic_state *pic)
{
pic_defun(pic, "identifier?", pic_macro_identifier_p);
pic_defun(pic, "identifier=?", pic_macro_identifier_eq_p);
pic_defun(pic, "make-identifier", pic_macro_make_identifier);
}