lower: 옵셔널, 에러 유니온, try/catch/orelse, defer, for

옵셔널은 태그와 페이로드, 에러 유니온은 오류 코드와 페이로드다. 코드 0 이
'오류 없음'이다. 페이로드 위치 규칙을 types.c 로 옮겨서 레이아웃 패스와 코드
생성기가 같은 것을 본다.

try 는 분기다. 실패면 지금 함수의 에러 유니온을 그 코드로 만들어 나간다 --
그 전에 defer 를 돌린다. catch 와 orelse 는 오른쪽을 필요할 때만 평가하므로
역시 분기다.

for 는 세 형태를 공유한다: 세는 것, 원소를 도는 것, 위치까지 받는 것. 개수는
본문 전에 한 번 읽는다. 원소 바인딩은 참조다 -- 그래서 루프가 원본에 쓸 수
있다.

error.Name 은 빌드 전체에서 이름을 모아 철자 순으로 1부터 번호를 준다
(SPEC 4.6). 빌드 순서가 결과를 바꾸지 않는다.

run.py 197/197, exec.py 9/9.
This commit is contained in:
2026-08-17 06:06:35 +09:00
parent 43555b261c
commit 096a5db411
6 changed files with 485 additions and 2 deletions
+423 -2
View File
@@ -1,5 +1,6 @@
#include "lower.h"
#include <string.h>
#include "m7.h"
#include <stdio.h>
/* ------------------------------------------------------------------------- *
@@ -35,6 +36,16 @@ typedef struct Lower {
unsigned break_target[32];
unsigned continue_target[32];
unsigned loop_depth;
/* `defer` blocks in the order they were written. Every exit path runs the
ones that are live, last written first. */
FeNode *deferred[32];
unsigned defer_count;
/* Every `error.Name` used anywhere in the build, sorted, numbered from one.
SPEC 4.6: the names are collected rather than declared, and the order is
fixed by the spelling so that the same program always gets the same
codes however the build was ordered. */
const char *error_names[256];
unsigned error_count;
int failed;
} Lower;
@@ -50,6 +61,19 @@ static Slot lower_expr(Lower *L, FeNode *n);
static void lower_stmt(Lower *L, FeNode *n);
static void store_into(Lower *L, FeIrPlace dst, Slot value, FeNode *n,
unsigned long size);
static void lower_for(Lower *L, FeNode *n);
static Slot wrap_context(Lower *L, Slot v, FeNode *n);
static Slot lower_try(Lower *L, FeNode *n);
static Slot lower_lazy(Lower *L, FeNode *n, int is_catch);
static Slot wrapper_payload(Lower *L, Slot w, const FeType *t);
static unsigned scratch(Lower *L, const FeType *t, const char *why);
static int uses_niche(const FeType *t);
static FeIrType tag_type(const FeType *t);
static void run_deferred(Lower *L, unsigned from);
static unsigned declare_var(Lower *L, const char *cname, const FeType *t,
const char *name);
static void indexable_parts(Lower *L, Slot base, const FeType *t,
unsigned *data, unsigned *length, FeNode *n);
static void fail(Lower *L, const char *why, FeNode *n)
{
@@ -204,6 +228,19 @@ static void guard(Lower *L, unsigned ok, FeIrTrap reason, unsigned long line)
L->b = cont;
}
/* A tag says which of the two things a wrapper holds. An optional is one byte
at the front unless the payload has a spare representation; an error union is
a two-byte error code, and zero means there is no error. */
static FeIrType tag_type(const FeType *t)
{
return t && t->kind == FE_TYPE_ERROR_UNION ? FE_IR_I16 : FE_IR_I8;
}
static int uses_niche(const FeType *t)
{
return t && t->kind == FE_TYPE_OPTIONAL && fe_m7_optional_uses_niche(t->elem);
}
/* Somewhere to build an aggregate that has no home of its own yet. */
static unsigned scratch(Lower *L, const FeType *t, const char *why)
{
@@ -235,6 +272,46 @@ static void indexable_parts(Lower *L, Slot base, const FeType *t,
}
}
/* ------------------------------------------------------- error codes ----- */
static void note_error_name(Lower *L, const char *name)
{
unsigned i;
unsigned at;
if (!name || L->error_count >= 256) return;
for (i = 0; i < L->error_count; ++i)
if (!strcmp(L->error_names[i], name)) return;
/* Kept sorted as it is built, so the numbering is the spelling order. */
at = L->error_count;
while (at > 0 && strcmp(L->error_names[at - 1], name) > 0) {
L->error_names[at] = L->error_names[at - 1];
--at;
}
L->error_names[at] = name;
++L->error_count;
}
static void collect_error_names(Lower *L, FeNode *n)
{
FeNode *x;
if (!n) return;
if (n->kind == FE_N_MEMBER && n->a && n->a->kind == FE_N_IDENT &&
n->a->text && !strcmp(n->a->text, "error") && n->b && n->b->text)
note_error_name(L, n->b->text);
collect_error_names(L, n->a);
collect_error_names(L, n->b);
collect_error_names(L, n->c);
for (x = n->children; x; x = x->next) collect_error_names(L, x);
}
static long error_code(Lower *L, const char *name)
{
unsigned i;
for (i = 0; i < L->error_count; ++i)
if (!strcmp(L->error_names[i], name)) return (long)(i + 1);
return 0;
}
/* ---------------------------------------------------------- expressions --- */
static FeIrOp binary_op(const char *op, int *is_cmp)
@@ -363,7 +440,19 @@ static Slot lower_call(Lower *L, FeNode *n)
return slot_value(fe_ir_call(L->m, L->b, rt, callee, args, count), rt);
}
static Slot lower_expr_core(Lower *L, FeNode *n);
/* Every expression may be standing where a wrapper is expected, so the wrap is
applied once, here, rather than at each place that could need it. */
static Slot lower_expr(Lower *L, FeNode *n)
{
Slot v;
if (!n || L->failed) return slot_void();
v = lower_expr_core(L, n);
return n->sem_context ? wrap_context(L, v, n) : v;
}
static Slot lower_expr_core(Lower *L, FeNode *n)
{
FeType *t;
FeIrType it;
@@ -397,6 +486,8 @@ static Slot lower_expr(Lower *L, FeNode *n)
unsigned a;
unsigned b;
FeIrType operand;
if (n->text && !strcmp(n->text, "orelse")) return lower_lazy(L, n, 0);
if (n->text && !strcmp(n->text, "catch")) return lower_lazy(L, n, 1);
if (n->text && (!strcmp(n->text, "and") || !strcmp(n->text, "or")))
return lower_logical(L, n, !strcmp(n->text, "and"));
op = binary_op(n->text, &is_cmp);
@@ -410,6 +501,7 @@ static Slot lower_expr(Lower *L, FeNode *n)
is_cmp ? FE_IR_I8 : operand);
}
case FE_N_UNARY:
if (n->text && !strcmp(n->text, "try")) return lower_try(L, n);
if (n->text && !strcmp(n->text, "-")) {
unsigned zero = fe_ir_const(L->m, L->b, it, 0);
unsigned v = as_value(L, lower_expr(L, n->a), n->a);
@@ -429,6 +521,19 @@ static Slot lower_expr(Lower *L, FeNode *n)
fail(L, "this unary operator", n);
return slot_void();
case FE_N_MEMBER:
/* `error.Name` is a member of the open default set: a code, and
nothing to look up. */
if (n->a && n->a->kind == FE_N_IDENT && n->a->text &&
!strcmp(n->a->text, "error") && n->b && n->b->text)
return slot_value(fe_ir_const(L->m, L->b, FE_IR_I16,
error_code(L, n->b->text)),
FE_IR_I16);
/* `.?` is the payload of an optional the checker already proved is
there. */
if (n->text && !strcmp(n->text, ".?")) {
FeType *bt = n->a ? n->a->sem_type : 0;
return wrapper_payload(L, lower_expr(L, n->a), bt);
}
/* `p.^` reads through a pointer. */
if (n->text && !strcmp(n->text, ".^")) {
unsigned p = as_value(L, lower_expr(L, n->a), n->a);
@@ -529,6 +634,168 @@ static Slot lower_expr(Lower *L, FeNode *n)
}
}
/* Run the `defer` blocks that are live, most recent first. A `return` in the
middle of a function still owes them, so every exit path calls this. */
static void run_deferred(Lower *L, unsigned from)
{
unsigned i;
for (i = L->defer_count; i > from; --i) lower_stmt(L, L->deferred[i - 1]);
}
/* ------------------------------------------------------- wrappers -------- *
* An optional is a tag and a payload; an error union is an error code and a
* payload, where a code of zero means there is no error. Both are memory, and
* both are built the same way: write the tag, then write the value after it.
* -------------------------------------------------------------------------- */
static Slot wrap_context(Lower *L, Slot v, FeNode *n)
{
FeType *want = n->sem_context;
unsigned local;
long payload_at;
if (!want) return v;
local = scratch(L, want, "wrapped");
payload_at = (long)fe_type_payload_offset(want);
if (want->kind == FE_TYPE_OPTIONAL) {
if (fe_m7_is_null(n)) {
/* A payload with a spare representation uses it for "nothing"
instead of carrying a separate tag. */
unsigned z = fe_ir_const(L->m, L->b,
uses_niche(want) ? FE_IR_PTR : FE_IR_I8, 0);
fe_ir_store(L->m, L->b, fe_ir_at_local(local, 0), z,
uses_niche(want) ? FE_IR_PTR : FE_IR_I8);
return slot_place(fe_ir_at_local(local, 0), FE_IR_MEM, ir_size(want));
}
if (!uses_niche(want)) {
unsigned one = fe_ir_const(L->m, L->b, FE_IR_I8, 1);
fe_ir_store(L->m, L->b, fe_ir_at_local(local, 0), one, FE_IR_I8);
}
store_into(L, fe_ir_at_local(local, payload_at), v, n,
ir_size(want->elem));
return slot_place(fe_ir_at_local(local, 0), FE_IR_MEM, ir_size(want));
}
if (want->kind == FE_TYPE_ERROR_UNION) {
FeType *value_type = want->error_value;
if (n->sem_type && n->sem_type->is_error) {
fe_ir_store(L->m, L->b, fe_ir_at_local(local, 0),
as_value(L, v, n), FE_IR_I16);
} else {
unsigned zero = fe_ir_const(L->m, L->b, FE_IR_I16, 0);
fe_ir_store(L->m, L->b, fe_ir_at_local(local, 0), zero, FE_IR_I16);
if (value_type && value_type->kind != FE_TYPE_VOID)
store_into(L, fe_ir_at_local(local, payload_at), v, n,
ir_size(value_type));
}
return slot_place(fe_ir_at_local(local, 0), FE_IR_MEM, ir_size(want));
}
return v;
}
/* The tag of a wrapper that is already in memory. */
static unsigned wrapper_tag(Lower *L, Slot w, const FeType *t, FeNode *n)
{
FeIrPlace p;
if (!w.is_place) { fail(L, "a wrapper with no place", n); return 0; }
p = w.place;
if (uses_niche(t)) return fe_ir_load(L->m, L->b, FE_IR_PTR, p);
return fe_ir_load(L->m, L->b, tag_type(t), p);
}
static Slot wrapper_payload(Lower *L, Slot w, const FeType *t)
{
FeType *payload = t ? (t->kind == FE_TYPE_ERROR_UNION ? t->error_value
: t->elem) : 0;
FeIrPlace p = w.place;
(void)L;
p.offset += (long)fe_type_payload_offset(t);
return slot_place(p, ir_type(payload), ir_size(payload));
}
/* Leave the function with this error code, after the deferred blocks. */
static void return_error(Lower *L, unsigned err, FeNode *n)
{
FeType *ret = L->ret_type;
unsigned local = scratch(L, ret, "failure");
fe_ir_store(L->m, L->b, fe_ir_at_local(local, 0), err, FE_IR_I16);
run_deferred(L, 0);
if (L->fn->returns_by_address) {
unsigned dst = fe_ir_load(L->m, L->b, FE_IR_PTR,
fe_ir_at_local(L->ret_local, 0));
fe_ir_copy(L->m, L->b, fe_ir_at_temp(dst, 0), fe_ir_at_local(local, 0),
ir_size(ret));
fe_ir_ret(L->b, 0, 0);
return;
}
fe_ir_ret(L->b, fe_ir_load(L->m, L->b, ir_type(ret),
fe_ir_at_local(local, 0)), 1);
(void)n;
}
/* `try e` -- if e failed, leave with its error; otherwise the value. */
static Slot lower_try(Lower *L, FeNode *n)
{
FeType *t = n->a ? n->a->sem_type : 0;
Slot e = lower_expr(L, n->a);
unsigned err = wrapper_tag(L, e, t, n);
unsigned zero = fe_ir_const(L->m, L->b, FE_IR_I16, 0);
unsigned ok = fe_ir_binary(L->m, L->b, FE_IR_EQ, FE_IR_I16, err, zero, 1);
FeIrBlock *bad = new_block(L);
FeIrBlock *good = new_block(L);
fe_ir_br(L->b, ok, good->id, bad->id);
L->b = bad;
return_error(L, err, n);
L->b = good;
return wrapper_payload(L, e, t);
}
/* `e orelse d` and `e catch d` both mean "the value, or that instead". The
right-hand side is only evaluated when it is needed, so it is a branch. */
static Slot lower_lazy(Lower *L, FeNode *n, int is_catch)
{
FeType *t = n->a ? n->a->sem_type : 0;
FeType *payload = t ? (is_catch ? t->error_value : t->elem) : 0;
Slot e;
unsigned tag;
unsigned zero;
unsigned ok;
unsigned result;
FeIrBlock *other;
FeIrBlock *join;
FeIrBlock *have;
e = lower_expr(L, n->a);
tag = wrapper_tag(L, e, t, n);
zero = fe_ir_const(L->m, L->b, is_catch || uses_niche(t) ? FE_IR_PTR
: FE_IR_I8, 0);
/* An error union is fine when its code is zero; an optional is fine when
its tag is not. */
ok = fe_ir_binary(L->m, L->b, is_catch ? FE_IR_EQ : FE_IR_NE,
is_catch ? FE_IR_I16 : (uses_niche(t) ? FE_IR_PTR
: FE_IR_I8),
tag, zero, 1);
result = scratch(L, payload, "result");
have = new_block(L);
other = new_block(L);
join = new_block(L);
fe_ir_br(L->b, ok, have->id, other->id);
L->b = have;
store_into(L, fe_ir_at_local(result, 0), wrapper_payload(L, e, t), n,
ir_size(payload));
fe_ir_jmp(L->b, join->id);
L->b = other;
if (is_catch && n->c) {
/* The block form handles the error and must not fall through with a
value, so whatever it leaves behind is what the checker allowed. */
lower_stmt(L, n->c);
} else {
Slot d = lower_expr(L, n->b);
store_into(L, fe_ir_at_local(result, 0), d, n->b, ir_size(payload));
}
fe_ir_jmp(L->b, join->id);
L->b = join;
return slot_place(fe_ir_at_local(result, 0), ir_type(payload),
ir_size(payload));
}
/* ----------------------------------------------------------- statements --- */
static void store_into(Lower *L, FeIrPlace dst, Slot value, FeNode *n,
@@ -545,8 +812,13 @@ static void store_into(Lower *L, FeIrPlace dst, Slot value, FeNode *n,
static void lower_return(Lower *L, FeNode *n)
{
Slot v;
if (!n->a) { fe_ir_ret(L->b, 0, 0); return; }
if (!n->a) { run_deferred(L, 0); fe_ir_ret(L->b, 0, 0); return; }
/* The value is computed before the deferred blocks run, because they may
destroy what it was read from. */
v = lower_expr(L, n->a);
if (v.type != FE_IR_MEM && v.is_place)
v = slot_value(as_value(L, v, n->a), v.type);
run_deferred(L, 0);
if (L->fn->returns_by_address) {
unsigned dst = fe_ir_load(L->m, L->b, FE_IR_PTR,
fe_ir_at_local(L->ret_local, 0));
@@ -597,14 +869,153 @@ static void lower_while(Lower *L, FeNode *n)
L->b = done;
}
/* Three shapes share the keyword.
for i in a..b { } counts
for x in thing { } walks, binding a reference to each element
for i, x in thing { } walks, binding the position as well
The count is read once before the body, so a thing that grows underneath the
loop cannot walk past what was measured. The element binding is a reference
(`x.^` reads it), which is what lets a loop write back into the thing. */
static void lower_for(Lower *L, FeNode *n)
{
FeIrBlock *head;
FeIrBlock *body;
FeIrBlock *step;
FeIrBlock *done;
unsigned counter;
unsigned limit;
if (n->c) {
/* The counting form: the variable is the count itself. */
unsigned from = as_value(L, lower_expr(L, n->a), n->a);
unsigned to;
counter = declare_var(L, n->cname, 0, n->text);
L->fn->locals[counter].type = FE_IR_I32;
L->fn->locals[counter].size = 4;
L->fn->locals[counter].align = 4;
fe_ir_store(L->m, L->b, fe_ir_at_local(counter, 0), from, FE_IR_I32);
to = as_value(L, lower_expr(L, n->c), n->c);
limit = fe_ir_local(L->m, L->fn, FE_IR_I32, 4, 4, "limit");
fe_ir_store(L->m, L->b, fe_ir_at_local(limit, 0), to, FE_IR_I32);
head = new_block(L);
body = new_block(L);
step = new_block(L);
done = new_block(L);
fe_ir_jmp(L->b, head->id);
L->b = head;
{
unsigned i = fe_ir_load(L->m, L->b, FE_IR_I32,
fe_ir_at_local(counter, 0));
unsigned e = fe_ir_load(L->m, L->b, FE_IR_I32,
fe_ir_at_local(limit, 0));
unsigned more = fe_ir_binary(L->m, L->b, FE_IR_LT, FE_IR_I32, i, e, 1);
fe_ir_br(L->b, more, body->id, done->id);
}
} else {
FeType *bt = n->a ? n->a->sem_type : 0;
FeType *elem = bt ? bt->elem : 0;
Slot base = lower_expr(L, n->a);
unsigned data;
unsigned length;
unsigned data_local;
unsigned item;
indexable_parts(L, base, bt, &data, &length, n);
data_local = fe_ir_local(L->m, L->fn, FE_IR_PTR, 4, 4, "data");
fe_ir_store(L->m, L->b, fe_ir_at_local(data_local, 0), data, FE_IR_PTR);
limit = fe_ir_local(L->m, L->fn, FE_IR_I32, 4, 4, "count");
fe_ir_store(L->m, L->b, fe_ir_at_local(limit, 0), length, FE_IR_I32);
/* With two names the first is the position and the second the element;
with one it is the element. */
counter = fe_ir_local(L->m, L->fn, FE_IR_I32, 4, 4, "index");
if (n->aux_cname) {
L->vars[L->var_count].cname = n->cname;
L->vars[L->var_count].local = counter;
L->vars[L->var_count].by_address = 0;
if (L->var_count < LOWER_MAX_LOCALS) ++L->var_count;
item = fe_ir_local(L->m, L->fn, FE_IR_PTR, 4, 4, n->aux_text);
L->vars[L->var_count].cname = n->aux_cname;
L->vars[L->var_count].local = item;
L->vars[L->var_count].by_address = 0;
if (L->var_count < LOWER_MAX_LOCALS) ++L->var_count;
} else {
item = fe_ir_local(L->m, L->fn, FE_IR_PTR, 4, 4, n->text);
L->vars[L->var_count].cname = n->cname;
L->vars[L->var_count].local = item;
L->vars[L->var_count].by_address = 0;
if (L->var_count < LOWER_MAX_LOCALS) ++L->var_count;
}
{
unsigned zero = fe_ir_const(L->m, L->b, FE_IR_I32, 0);
fe_ir_store(L->m, L->b, fe_ir_at_local(counter, 0), zero, FE_IR_I32);
}
head = new_block(L);
body = new_block(L);
step = new_block(L);
done = new_block(L);
fe_ir_jmp(L->b, head->id);
L->b = head;
{
unsigned i = fe_ir_load(L->m, L->b, FE_IR_I32,
fe_ir_at_local(counter, 0));
unsigned e = fe_ir_load(L->m, L->b, FE_IR_I32,
fe_ir_at_local(limit, 0));
unsigned more = fe_ir_binary(L->m, L->b, FE_IR_LT, FE_IR_I32, i, e, 1);
fe_ir_br(L->b, more, body->id, done->id);
}
L->b = body;
{
unsigned i = fe_ir_load(L->m, L->b, FE_IR_I32,
fe_ir_at_local(counter, 0));
unsigned scale = fe_ir_const(L->m, L->b, FE_IR_I32,
(long)ir_size(elem));
unsigned off = fe_ir_binary(L->m, L->b, FE_IR_MUL, FE_IR_I32, i,
scale, 1);
unsigned p = fe_ir_load(L->m, L->b, FE_IR_PTR,
fe_ir_at_local(data_local, 0));
unsigned at = fe_ir_binary(L->m, L->b, FE_IR_ADD, FE_IR_PTR, p,
off, 1);
fe_ir_store(L->m, L->b, fe_ir_at_local(item, 0), at, FE_IR_PTR);
}
L->b = head;
}
if (L->loop_depth < 32) {
L->break_target[L->loop_depth] = done->id;
L->continue_target[L->loop_depth] = step->id;
++L->loop_depth;
}
L->b = body;
lower_stmt(L, n->b);
fe_ir_jmp(L->b, step->id);
L->b = step;
{
unsigned i = fe_ir_load(L->m, L->b, FE_IR_I32,
fe_ir_at_local(counter, 0));
unsigned one = fe_ir_const(L->m, L->b, FE_IR_I32, 1);
unsigned next = fe_ir_binary(L->m, L->b, FE_IR_ADD, FE_IR_I32, i, one, 1);
fe_ir_store(L->m, L->b, fe_ir_at_local(counter, 0), next, FE_IR_I32);
}
fe_ir_jmp(L->b, head->id);
if (L->loop_depth) --L->loop_depth;
L->b = done;
}
static void lower_stmt(Lower *L, FeNode *n)
{
FeNode *x;
if (!n || L->failed) return;
switch (n->kind) {
case FE_N_BLOCK:
case FE_N_BLOCK: {
unsigned outer = L->defer_count;
for (x = n->children; x; x = x->next) lower_stmt(L, x);
/* Leaving a block normally runs what it deferred. An exit that jumped
away already ran them on its way out. */
if (!L->b->terminated) run_deferred(L, outer);
L->defer_count = outer;
return;
}
case FE_N_LET:
case FE_N_VAR:
case FE_N_CONST: {
@@ -644,6 +1055,12 @@ static void lower_stmt(Lower *L, FeNode *n)
case FE_N_UNSAFE:
lower_stmt(L, n->a);
return;
case FE_N_DEFER:
if (L->defer_count < 32) L->deferred[L->defer_count++] = n->a;
return;
case FE_N_FOR:
lower_for(L, n);
return;
default:
fail(L, "this statement", n);
return;
@@ -697,6 +1114,10 @@ int fe_lower_program(FeCheck *c, FeIrModule *out)
memset(&L, 0, sizeof L);
L.c = c;
L.m = out;
/* The codes have to be known while the bodies are lowered, so the names
are gathered from the whole build first. */
for (u = 0; u < c->build->count; ++u)
collect_error_names(&L, c->build->units[u].ast.root);
for (u = 0; u < c->build->count; ++u) {
FeUnit *unit = &c->build->units[u];
c->ast = &unit->ast;
+14
View File
@@ -417,6 +417,20 @@ unsigned long fe_type_size(const FeType *t)
return t ? t->size : 0;
}
unsigned long fe_type_payload_offset(const FeType *t)
{
if (!t) return 0;
if (t->kind == FE_TYPE_ERROR_UNION) {
if (!t->error_value || t->error_value->kind == FE_TYPE_VOID) return 2;
return round_up(2UL, fe_type_align(t->error_value));
}
if (t->kind == FE_TYPE_OPTIONAL) {
if (fe_m7_optional_uses_niche(t->elem)) return 0;
return round_up(1UL, fe_type_align(t->elem));
}
return 0;
}
unsigned fe_type_align(const FeType *t)
{
return t && t->align ? t->align : 1U;
+4
View File
@@ -137,6 +137,10 @@ int fe_type_is_integer(const FeType *t);
int fe_type_is_indexable(const FeType *t);
const char *fe_type_c_name(const FeType *t, unsigned pointer_bits);
unsigned long fe_type_size(const FeType *t);
/* Where the payload of an optional or an error union sits. The tag comes
first and the value is aligned after it; both the layout pass and the
code generator have to agree, so the rule lives in one place. */
unsigned long fe_type_payload_offset(const FeType *t);
unsigned fe_type_align(const FeType *t);
#endif
+18
View File
@@ -0,0 +1,18 @@
// EXIT:9
unit errunion;
fn half(v: i32) -> !i32 {
if v == 0 { return error.Empty; }
return v / 2;
}
fn chain(v: i32) -> !i32 {
let h: i32 = try half(v);
return h + 1;
}
fn main() -> i32 {
let good: i32 = chain(16) catch 100;
let bad: i32 = chain(0) catch 0;
return good + bad;
}
+11
View File
@@ -0,0 +1,11 @@
// EXIT:60
unit forloop;
fn main() -> i32 {
let a: [5]i32 = [4, 8, 12, 16, 20];
var sum: i32 = 0;
for v in a {
sum = sum + v.^;
}
return sum;
}
+15
View File
@@ -0,0 +1,15 @@
// EXIT:42
unit optional;
fn pick(flag: bool) -> ?i32 {
if flag { return 42; }
return null;
}
fn main() -> i32 {
let a: ?i32 = pick(true);
let b: ?i32 = pick(false);
let x: i32 = a orelse 0;
let y: i32 = b orelse 0;
return x + y;
}