Files
sx/examples/1009-errors-catch.sx
agra d8076b9333 lang: rename signed integer types sN -> iN
Surface rename of the signed integer family: s1..s64 become i1..i64
(u1..u64, usize, isize unchanged). 'string' keeps the s-prefix arm in
name classification; width parsing moves to the i-prefix arm next to
isize.

Internal TypeId tags follow the surface (.s8/.s16/.s32/.s64 ->
.i8/.i16/.i32/.i64), as do mono-key mangle fragments (ptr_i64,
tu_i64_bool) and all display/diagnostic formatting (i{d}).

Migrated in the same sweep: stdlib + examples + issue repros + FFI C
companions (shared symbol names like ffi_id_i64), expected
stdout/stderr/ir snapshots, specs.md, readme.md, CLAUDE.md/AGENTS.md,
implementation_plan.md, docs/, issue writeups. Vendored stb_image and
historical flow state left untouched.

zig build test: 426/426; examples suite: 595/595.
2026-06-12 09:31:53 +03:00

65 lines
2.5 KiB
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// `catch` on a pure-failable LHS (ERR step E1.5). `expr catch [e] BODY`
// consumes the error inline: on failure it binds the tag to `e` (optional)
// and runs BODY; on success the result is void (a `-> !` LHS has no success
// value). BODY may diverge (`return` / `raise` — typed `noreturn`, E1.4c) or
// fall through. `catch` needs no failable *enclosing* function — it handles
// the error locally. All four body forms appear below: block, no-binding
// block, match-body (`== { case ... }`), and the selective handle + re-raise
// pattern. Value-carrying `-> (T, !)` catch (binding the success value) lands
// with the tuple ABI in E2.
#import "modules/std.sx";
E :: error { Bad, Empty }
must :: (n: i32) -> !E {
if n < 0 { raise error.Bad; }
if n == 0 { raise error.Empty; }
return;
}
// Diverging body — returns from `classify` on error.
classify :: (n: i32) -> i32 {
must(n) catch (e) {
if e == error.Bad { return 1; }
if e == error.Empty { return 2; }
return 9;
};
return 0; // must(n) succeeded
}
// Match-body form — sugar for `catch (e) { if e == { case ... } }`.
mclassify :: (n: i32) -> i32 {
must(n) catch (e) == {
case .Bad: return 11;
case .Empty: return 22;
else: return 99;
};
return 0;
}
// Selective handle + re-raise (failable enclosing fn; `raise e` is the
// variable form). Swallows Bad → success; re-raises everything else.
handle_some :: (n: i32) -> !E {
must(n) catch (e) {
if e == error.Bad { return; } // swallow → success
raise e; // re-raise the rest
};
return;
}
main :: () -> i32 {
r : i32 = 0;
must(-1) catch (e) { if e == error.Bad { r = r + 1; } }; // Bad → +1
must(5) catch { r = r + 100; }; // success → body skipped
r = r + classify(0); // Empty → 2
r = r + classify(8); // success → 0
he := handle_some(0); // Empty re-raised
if he == error.Empty { r = r + 4; } // +4
hb := handle_some(-1); // Bad swallowed → success
if hb == error.Bad { r = r + 50; } // not taken
r = r + mclassify(-1); // Bad → 11
print("catch result: {}\n", r); // 1+2+4+11 = 18
return r;
}