picrin/macro.c

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/**
* See Copyright Notice in picrin.h
*/
#include "picrin.h"
#include "picrin/pair.h"
#include "picrin/string.h"
#include "picrin/proc.h"
#include "picrin/macro.h"
#include "picrin/lib.h"
#include "picrin/error.h"
#include "picrin/dict.h"
#include "picrin/cont.h"
pic_sym
pic_add_rename(pic_state *pic, struct pic_senv *senv, pic_sym sym)
{
pic_sym rename;
rename = pic_gensym(pic, sym);
pic_put_rename(pic, senv, sym, rename);
return rename;
}
void
pic_put_rename(pic_state *pic, struct pic_senv *senv, pic_sym sym, pic_sym rename)
{
UNUSED(pic);
xh_put_int(&senv->map, sym, &rename);
}
bool
pic_find_rename(pic_state *pic, struct pic_senv *senv, pic_sym sym, pic_sym *rename)
{
xh_entry *e;
UNUSED(pic);
if ((e = xh_get_int(&senv->map, sym)) == NULL) {
return false;
}
if (rename != NULL) {
*rename = xh_val(e, pic_sym);
}
return true;
}
static void
define_macro(pic_state *pic, pic_sym rename, struct pic_proc *proc, struct pic_senv *senv)
{
struct pic_macro *mac;
mac = (struct pic_macro *)pic_obj_alloc(pic, sizeof(struct pic_macro), PIC_TT_MACRO);
mac->senv = senv;
mac->proc = proc;
xh_put_int(&pic->macros, rename, &mac);
}
static struct pic_macro *
find_macro(pic_state *pic, pic_sym rename)
{
xh_entry *e;
if ((e = xh_get_int(&pic->macros, rename)) == NULL) {
return NULL;
}
return xh_val(e, struct pic_macro *);
}
static pic_sym
make_identifier(pic_state *pic, pic_sym sym, struct pic_senv *senv)
{
pic_sym rename;
while (true) {
if (pic_find_rename(pic, senv, sym, &rename)) {
return rename;
}
if (! senv->up)
break;
senv = senv->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_senv *);
static pic_value macroexpand_lambda(pic_state *, pic_value, struct pic_senv *);
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static pic_value
macroexpand_symbol(pic_state *pic, pic_sym sym, struct pic_senv *senv)
{
return pic_sym_value(make_identifier(pic, sym, senv));
}
static pic_value
macroexpand_quote(pic_state *pic, pic_value expr)
{
return pic_cons(pic, pic_sym_value(pic->rQUOTE), pic_cdr(pic, expr));
}
static pic_value
macroexpand_list(pic_state *pic, pic_value obj, struct pic_senv *senv)
{
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), senv);
tail = macroexpand_list(pic, pic_cdr(pic, obj), senv);
x = pic_cons(pic, head, tail);
} else {
x = macroexpand(pic, obj, senv);
}
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_senv *senv)
{
pic_value skel = pic_list1(pic, pic_none_value()); /* (#<none>) */
pic_push(pic, pic_cons(pic, expr, skel), senv->defer);
return skel;
}
static void
macroexpand_deferred(pic_state *pic, struct pic_senv *senv)
{
pic_value defer, val, src, dst;
pic_for_each (defer, pic_reverse(pic, senv->defer)) {
src = pic_car(pic, defer);
dst = pic_cdr(pic, defer);
val = macroexpand_lambda(pic, src, senv);
/* copy */
pic_pair_ptr(dst)->car = pic_car(pic, val);
pic_pair_ptr(dst)->cdr = pic_cdr(pic, val);
}
senv->defer = pic_nil_value();
}
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static pic_value
macroexpand_lambda(pic_state *pic, pic_value expr, struct pic_senv *senv)
{
pic_value formal, body;
struct pic_senv *in;
pic_value a;
if (pic_length(pic, expr) < 2) {
pic_error(pic, "syntax error");
}
in = pic_senv_new(pic, senv);
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_error(pic, "syntax error");
}
pic_add_rename(pic, in, pic_sym(v));
}
if (pic_sym_p(a)) {
pic_add_rename(pic, in, pic_sym(a));
}
else if (! pic_nil_p(a)) {
pic_error(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);
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return pic_cons(pic, pic_sym_value(pic->rLAMBDA), pic_cons(pic, formal, body));
}
static pic_value
macroexpand_define(pic_state *pic, pic_value expr, struct pic_senv *senv)
{
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_sym_value(pic->rDEFINE), var, pic_cons(pic, pic_sym_value(pic->rLAMBDA), pic_cons(pic, val, pic_cddr(pic, expr))));
}
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if (pic_length(pic, expr) != 3) {
pic_error(pic, "syntax error");
}
var = pic_cadr(pic, expr);
if (! pic_sym_p(var)) {
pic_error(pic, "binding to non-symbol object");
}
sym = pic_sym(var);
if (! pic_find_rename(pic, senv, sym, &rename)) {
rename = pic_add_rename(pic, senv, sym);
}
val = macroexpand(pic, pic_list_ref(pic, expr, 2), senv);
return pic_list3(pic, pic_sym_value(pic->rDEFINE), pic_sym_value(rename), val);
}
static pic_value
macroexpand_defsyntax(pic_state *pic, pic_value expr, struct pic_senv *senv)
{
pic_value var, val;
pic_sym sym, rename;
if (pic_length(pic, expr) != 3) {
pic_error(pic, "syntax error");
}
var = pic_cadr(pic, expr);
if (! pic_sym_p(var)) {
pic_error(pic, "binding to non-symbol object");
}
sym = pic_sym(var);
if (! pic_find_rename(pic, senv, sym, &rename)) {
rename = pic_add_rename(pic, senv, sym);
} else {
pic_warnf(pic, "redefining syntax variable: ~s", pic_sym_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);
}
define_macro(pic, rename, pic_proc_ptr(val), senv);
return pic_none_value();
}
static pic_value
macroexpand_macro(pic_state *pic, struct pic_macro *mac, pic_value expr, struct pic_senv *senv)
{
pic_value v, args;
#if DEBUG
puts("before expand-1:");
pic_debug(pic, expr);
puts("");
#endif
if (mac->senv == NULL) { /* legacy macro */
args = pic_cdr(pic, expr);
} else {
args = pic_list3(pic, expr, pic_obj_value(senv), pic_obj_value(mac->senv));
}
pic_try {
v = pic_apply(pic, mac->proc, 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_senv *senv)
{
switch (pic_type(expr)) {
case PIC_TT_SYMBOL: {
return macroexpand_symbol(pic, pic_sym(expr), senv);
}
case PIC_TT_PAIR: {
pic_value car;
struct pic_macro *mac;
if (! pic_list_p(expr)) {
pic_errorf(pic, "cannot macroexpand improper list: ~s", expr);
}
car = macroexpand(pic, pic_car(pic, expr), senv);
if (pic_sym_p(car)) {
pic_sym tag = pic_sym(car);
if (tag == pic->rDEFINE_SYNTAX) {
return macroexpand_defsyntax(pic, expr, senv);
}
else if (tag == pic->rLAMBDA) {
return macroexpand_defer(pic, expr, senv);
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}
else if (tag == pic->rDEFINE) {
return macroexpand_define(pic, expr, senv);
}
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, senv), senv);
}
}
return pic_cons(pic, car, macroexpand_list(pic, pic_cdr(pic, expr), senv));
}
default:
return expr;
}
}
static pic_value
macroexpand(pic_state *pic, pic_value expr, struct pic_senv *senv)
{
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, senv);
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 */
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v = macroexpand(pic, expr, lib->env);
macroexpand_deferred(pic, lib->env);
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pic->lib = prev;
#if DEBUG
puts("after expand:");
pic_debug(pic, v);
puts("");
#endif
return v;
}
struct pic_senv *
pic_senv_new(pic_state *pic, struct pic_senv *up)
{
struct pic_senv *senv;
senv = (struct pic_senv *)pic_obj_alloc(pic, sizeof(struct pic_senv), PIC_TT_SENV);
senv->up = up;
senv->defer = pic_nil_value();
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xh_init_int(&senv->map, sizeof(pic_sym));
return senv;
}
struct pic_senv *
pic_null_syntactic_environment(pic_state *pic)
{
struct pic_senv *senv;
senv = pic_senv_new(pic, NULL);
pic_define_syntactic_keyword(pic, senv, pic->sDEFINE_LIBRARY, pic->rDEFINE_LIBRARY);
pic_define_syntactic_keyword(pic, senv, pic->sIMPORT, pic->rIMPORT);
pic_define_syntactic_keyword(pic, senv, pic->sEXPORT, pic->rEXPORT);
pic_define_syntactic_keyword(pic, senv, pic->sIN_LIBRARY, pic->rIN_LIBRARY);
pic_define_syntactic_keyword(pic, senv, pic->sCOND_EXPAND, pic->rCOND_EXPAND);
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return senv;
}
void
pic_define_syntactic_keyword(pic_state *pic, struct pic_senv *senv, pic_sym sym, pic_sym rsym)
{
pic_put_rename(pic, senv, sym, rsym);
if (pic->lib && pic->lib->env == senv) {
pic_export(pic, sym);
}
}
void
pic_defmacro(pic_state *pic, pic_sym name, pic_sym id, pic_func_t func)
{
pic_put_rename(pic, pic->lib->env, name, id);
/* symbol registration */
define_macro(pic, id, pic_proc_new(pic, func, pic_symbol_name(pic, name)), NULL);
/* 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(obj));
}
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bool
pic_identifier_eq_p(pic_state *pic, struct pic_senv *env1, pic_sym sym1, struct pic_senv *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_sym_value(a), pic_sym_value(b));
}
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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, senv);
return pic_sym_value(make_identifier(pic, sym, pic_senv_ptr(obj)));
}
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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, senv);
pic_assert_type(pic, env2, senv);
return pic_bool_value(pic_identifier_eq_p(pic, pic_senv_ptr(env1), sym1, pic_senv_ptr(env2), sym2));
}
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void
pic_init_macro(pic_state *pic)
{
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pic_defun(pic, "identifier?", pic_macro_identifier_p);
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pic_defun(pic, "identifier=?", pic_macro_identifier_eq_p);
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pic_defun(pic, "make-identifier", pic_macro_make_identifier);
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}