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Get returns working

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This commit is contained in:
Alexander Rosenberg
2025-09-19 14:41:32 -07:00
parent 2b7f9b2fd6
commit 342bdfb169
4 changed files with 175 additions and 77 deletions
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169
src/lisp.c
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@ -370,8 +370,8 @@ malformed:
Fthrow(Qmalformed_lambda_list_error, Fpair(args, Qnil));
}
LispVal *make_lisp_function(LispVal *name, LispVal *args, LispVal *lexenv,
LispVal *body, bool is_macro) {
LispVal *make_lisp_function(LispVal *name, LispVal *return_tag, LispVal *args,
LispVal *lexenv, LispVal *body, bool is_macro) {
CONSTRUCT_OBJECT(self, LispFunction, TYPE_FUNCTION);
self->is_builtin = false;
self->is_macro = is_macro;
@ -386,6 +386,7 @@ LispVal *make_lisp_function(LispVal *name, LispVal *args, LispVal *lexenv,
// do these after the potential throw
self->name = refcount_ref(name);
self->return_tag = refcount_ref(return_tag);
self->lexenv = refcount_ref(lexenv);
if (STRINGP(HEAD(body))) {
self->doc = refcount_ref(HEAD(body));
@ -687,7 +688,8 @@ DEF_STATIC_SYMBOL(toplevel, "toplevel");
void stack_enter(LispVal *name, LispVal *detail, bool inherit) {
StackFrame *frame = lisp_malloc(sizeof(StackFrame));
frame->name = (LispSymbol *) name;
frame->name = name;
frame->return_tag = Qnil;
frame->hidden = true;
frame->detail = detail;
frame->lexenv = Qnil;
@ -707,6 +709,7 @@ void stack_leave(void) {
StackFrame *frame = the_stack;
the_stack = the_stack->next;
refcount_unref(frame->name);
refcount_unref(frame->return_tag);
refcount_unref(frame->detail);
refcount_unref(frame->lexenv);
refcount_unref(frame->handlers);
@ -797,9 +800,18 @@ DEFUN(backtrace, "backtrace", (void) ) {
return head;
}
DEFUN(return_from, "return-from", (LispVal * name, LispVal *value)) {
// TODO actually write this
abort();
DEFMACRO(return_from, "return-from", (LispVal * name, LispVal *value)) {
Fthrow(Qreturn_frame_error, const_list(true, 2, name, value));
}
STATIC_DEFMACRO(internal_real_return, "internal-real-return",
(LispVal * name, LispVal *tag, LispVal *value)) {
for (StackFrame *cur = the_stack; cur; cur = cur->next) {
if (!NILP(cur->return_tag) && cur->return_tag == tag) {
Fthrow(cur->return_tag, const_list(true, 1, value));
}
}
Fthrow(Qreturn_frame_error, const_list(true, 2, name, value));
}
#pragma GCC diagnostic push
@ -938,6 +950,7 @@ static bool held_refs_callback(void *obj, RefcountList **held, void *ignored) {
case TYPE_FUNCTION: {
LispFunction *fn = obj;
*held = refcount_list_push(*held, fn->name);
*held = refcount_list_push(*held, fn->return_tag);
*held = refcount_list_push(*held, fn->args);
*held = refcount_list_push(*held, fn->kwargs);
*held = refcount_list_push(*held, fn->oargs);
@ -1000,6 +1013,8 @@ static void free_obj_callback(void *obj, void *ignored) {
lisp_free(obj);
}
static DECLARE_FUNCTION(set_for_return, (LispVal * entry, LispVal *dest));
void lisp_init(void) {
RefcountContext *ctx = refcount_make_context(
offsetof(LispVal, refcount), Qnil, held_refs_callback,
@ -1038,8 +1053,10 @@ void lisp_init(void) {
REGISTER_SYMBOL(no_applicable_method_error);
REGISTER_SYMBOL(return_frame_error);
refcount_init_static(Qtoplevel);
refcount_init_static(&_Qtoplevel_symnamestr);
// some stuff that musn't be user accesable
REGISTER_SYMBOL_NOINTERN(toplevel);
REGISTER_STATIC_FUNCTION(set_for_return, "(entry dest)", "");
REGISTER_STATIC_FUNCTION(internal_real_return, "(name tag value)", "");
REGISTER_FUNCTION(breakpoint, "(&opt id)", "Do nothing...");
REGISTER_FUNCTION(sethead, "(pair newval)",
@ -1313,6 +1330,7 @@ too_few:
static LispVal *call_builtin(LispVal *name, LispFunction *func, LispVal *args,
LispVal *args_lexenv) {
// builtin macros inherit their parents lexenv
if (func->is_macro) {
the_stack->lexenv = refcount_ref(args_lexenv);
}
@ -1501,6 +1519,23 @@ static LispVal *call_lisp_function(LispVal *name, LispFunction *func,
}
}
STATIC_DEFUN(set_for_return, "set-for-return",
(LispVal * entry, LispVal *dest)) {
LispVal *retval = HEAD(TAIL(HEAD(entry)));
Fsethead(dest, retval);
return Qnil;
}
static inline void setup_return_handler(LispVal *tag, LispVal *dest) {
LispVal *err_var = INTERN_STATIC("e");
LispVal *quoted_dest = const_list(false, 2, Qquote, dest);
LispVal *handler =
const_list(true, 4, err_var, Qset_for_return, err_var, quoted_dest);
refcount_unref(quoted_dest);
puthash(the_stack->handlers, tag, handler);
refcount_unref(handler);
}
static LispVal *call_function(LispVal *func, LispVal *args,
LispVal *args_lexenv, bool eval_args,
bool allow_macro) {
@ -1524,21 +1559,32 @@ static LispVal *call_function(LispVal *func, LispVal *args,
args = eval_function_args(args, args_lexenv);
}
LispVal *retval = Qnil;
// builtin macros inherit their parents lexenv
LispVal *return_ptr = Fpair(Qnil, Qnil);
void *return_cl_handle =
register_cleanup(refcount_unref_as_callback, return_ptr);
refcount_ref(args);
WITH_CLEANUP(args, {
WITH_PUSH_FRAME(
SYMBOLP(func) ? func : Qlambda, args,
WITH_PUSH_FRAME_NO_REF_HANDLING_THROWS(
refcount_ref(fobj->name), refcount_ref(args),
false, // make sure the lexenv is nil
{
the_stack->hidden = false;
if (!NILP(fobj->return_tag)) {
the_stack->return_tag = refcount_ref(fobj->return_tag);
setup_return_handler(fobj->return_tag, return_ptr);
}
if (fobj->is_builtin) {
retval = call_builtin(func, fobj, args, args_lexenv);
} else {
retval = call_lisp_function(func, fobj, args, args_lexenv);
}
},
{
retval = refcount_ref(HEAD(return_ptr)); //
});
});
cancel_cleanup(return_cl_handle);
refcount_unref(return_ptr);
cancel_cleanup(cl_handle);
return retval;
}
@ -1674,12 +1720,12 @@ DEFUN(macroexpand_toplevel, "macroexpand-toplevel", (LispVal * form)) {
}
// func should ref its return value
static LispVal *filter_body_tree(LispVal *form,
static LispVal *filter_body_form(LispVal *form,
LispVal *(*func)(LispVal *body,
void *user_data),
void *user_data) {
if (PAIRP(form)) {
LispVal *toplevel_orig = func(form, user_data);
LispVal *toplevel_orig = func(form, user_data);
if (PAIRP(toplevel_orig)) {
LispVal *toplevel;
WITH_CLEANUP(toplevel_orig, {
toplevel = Fcopy_list(toplevel_orig); //
@ -1689,24 +1735,46 @@ static LispVal *filter_body_tree(LispVal *form,
if (PAIRP(toplevel) && NILP(Feq(Qquote, HEAD(toplevel)))) {
FOREACH_TAIL(tail, TAIL(toplevel)) {
Fsethead(tail,
filter_body_tree(HEAD(tail), func, user_data));
filter_body_form(HEAD(tail), func, user_data));
}
}
cancel_cleanup(cl_handler);
});
return toplevel;
} else {
return refcount_ref(form);
return toplevel_orig;
}
return Qnil;
}
static LispVal *filter_body_tree(LispVal *body,
LispVal *(*func)(LispVal *body,
void *user_data),
void *user_data) {
LispVal *start = Qnil;
LispVal *end;
FOREACH(form, body) {
LispVal *filtered = filter_body_form(form, func, user_data);
if (NILP(start)) {
start = Fpair(filtered, Qnil);
end = start;
} else {
LispVal *new_end = Fpair(filtered, Qnil);
Fsettail(end, new_end);
refcount_unref(new_end);
end = new_end;
}
refcount_unref(filtered);
}
return start;
}
static LispVal *macroexpand_toplevel_as_callback(LispVal *form, void *ignored) {
return Fmacroexpand_toplevel(form);
}
DEFUN(macroexpand_all, "macroexpand-all", (LispVal * form)) {
return filter_body_tree(form, macroexpand_toplevel_as_callback, NULL);
return filter_body_form(form, macroexpand_toplevel_as_callback, NULL);
}
DEFUN(apply, "apply", (LispVal * function, LispVal *rest)) {
@ -2009,12 +2077,45 @@ static bool parse_function_declare(LispVal *form, LispVal **name_ptr) {
return false;
}
struct NameAndReturnTag {
LispVal *name;
LispVal *return_tag;
};
static LispVal *expand_function_body_callback(LispVal *body, void *data) {
return Fmacroexpand_toplevel(body);
struct NameAndReturnTag *name_and_return_tag = data;
LispVal *expansion = Fmacroexpand_toplevel(body);
// this mess checks that the call is exactly one of
// - (return-from 'symbol)
// - (return-from 'symbol val)
if (PAIRP(expansion) && HEAD(expansion) == Qreturn_from
&& PAIRP(TAIL(expansion)) && LISTP(TAIL(TAIL(expansion)))
&& NILP(TAIL(TAIL(TAIL(expansion)))) && SYMBOLP(HEAD(TAIL(expansion)))
&& HEAD(TAIL(expansion)) == name_and_return_tag->name) {
LispVal *retval = Qnil;
if (!NILP(TAIL(TAIL(expansion)))) {
retval = refcount_ref(HEAD(TAIL(TAIL(expansion))));
}
refcount_unref(expansion);
return const_list(false, 4, Qinternal_real_return,
refcount_ref(name_and_return_tag->name),
refcount_ref(name_and_return_tag->return_tag),
retval);
} else if (PAIRP(expansion) && HEAD(expansion) == Qinternal_real_return
&& list_length(expansion) == 4
&& HEAD(TAIL(expansion)) == name_and_return_tag->name
&& HEAD(TAIL(TAIL(expansion)))
!= name_and_return_tag->return_tag) {
Fsethead(TAIL(TAIL(expansion)), name_and_return_tag->return_tag);
}
return expansion;
}
static inline LispVal *expand_function_body(LispVal *body) {
return filter_body_tree(body, expand_function_body_callback, NULL);
static inline LispVal *expand_function_body(LispVal *name, LispVal *return_tag,
LispVal *body) {
return filter_body_tree(
body, expand_function_body_callback,
&(struct NameAndReturnTag) {.name = name, .return_tag = return_tag});
}
DEFMACRO(defun, "defun", (LispVal * name, LispVal *args, LispVal *body)) {
@ -2022,10 +2123,13 @@ DEFMACRO(defun, "defun", (LispVal * name, LispVal *args, LispVal *body)) {
if (parse_function_declare(HEAD(body), NULL)) {
body = TAIL(body);
}
LispVal *expanded_body = expand_function_body(body);
LispVal *return_tag =
make_lisp_symbol(LISPVAL(((LispSymbol *) name)->name));
LispVal *expanded_body = expand_function_body(name, return_tag, body);
LispVal *func = Qnil;
WITH_CLEANUP(expanded_body, {
func = make_lisp_function(name, args, the_stack->lexenv, body, false);
func = make_lisp_function(name, return_tag, args, the_stack->lexenv,
expanded_body, false);
});
refcount_unref(Ffset(name, func));
return func;
@ -2036,25 +2140,36 @@ DEFMACRO(defmacro, "defmacro", (LispVal * name, LispVal *args, LispVal *body)) {
if (parse_function_declare(HEAD(body), NULL)) {
body = TAIL(body);
}
LispVal *expanded_body = expand_function_body(body);
LispVal *return_tag =
make_lisp_symbol(LISPVAL(((LispSymbol *) name)->name));
LispVal *expanded_body = expand_function_body(name, return_tag, body);
LispVal *func = Qnil;
WITH_CLEANUP(expanded_body, {
func = make_lisp_function(name, args, the_stack->lexenv, body, true);
func = make_lisp_function(name, return_tag, args, the_stack->lexenv,
expanded_body, true);
});
refcount_unref(Ffset(name, func));
return func;
}
DEFMACRO(lambda, "lambda", (LispVal * args, LispVal *body)) {
LispVal *name = Qlambda;
LispVal *name = Qunbound;
if (parse_function_declare(HEAD(body), &name)) {
body = TAIL(body);
}
LispVal *return_tag;
if (name == Qunbound) {
name = Qlambda;
return_tag = make_lisp_symbol(LISPVAL(((LispSymbol *) Qnil)->name));
} else {
CHECK_TYPE(TYPE_SYMBOL, name);
return_tag = make_lisp_symbol(LISPVAL(((LispSymbol *) name)->name));
}
LispVal *expanded_body = Fmacroexpand_all(body);
LispVal *func = Qnil;
WITH_CLEANUP(expanded_body, {
func = make_lisp_function(name, args, the_stack->lexenv, expanded_body,
false);
func = make_lisp_function(name, return_tag, args, the_stack->lexenv,
expanded_body, false);
});
return func;
}