Files
sx/examples/1341-ffi-objc-dsl-01-niladic.sx
agra bdd0e96d78 feat(lang): block value requires no trailing ; (Rust-style)
A block's value is now its last statement ONLY when that statement is a
trailing expression with no `;`. A trailing `;` discards the value,
leaving the block void. This makes value-vs-statement explicit and lets
the compiler reject "this block was supposed to produce a value".

Compiler:
- Parser records `Block.produces_value` (last stmt is a no-`;` trailing
  expression) + `Block.discarded_semi` (the `;` that discarded a value),
  via `expectSemicolonAfter`. A trailing expression before `}` may now
  omit its `;` (previously a parse error). Match-arm and else-arm bodies
  are built value-producing regardless of the arm `;` (arms are exempt —
  the `;` is an arm terminator).
- Lowering: `lowerBlockValue` / the block-expr path / `inferExprType`
  respect `produces_value`. A value-position block that discards its value
  is a hard error (`lowerValueBody` for function bodies; the value-context
  `.block` path for if/else branches, `catch` bodies, value bindings,
  match arms). Pure-failable `-> !` bodies (value rides the error channel)
  and a value-if whose branches are void are handled without false errors.
- `defer`/`onfail` cleanup bodies lower as statements (void), so a
  trailing `;` there is fine.

Migration (behavior-preserving — output unchanged):
- stdlib + ~210 examples: dropped the trailing `;` on value-position last
  expressions. `format` now ends with an explicit `#insert "return
  result;"` (it relied on `#insert`-as-block-value, which `;` discards).
- Two `main :: () -> s32` examples that relied on the old silent
  default-return got an explicit trailing `0`.
- Rejection snapshots 0412 / 1013 regenerated (their quoted source lines
  lost a `;`); the diagnostics themselves are unchanged.

Docs/tests: specs.md "Block values" section; examples 0040 (rules) + 0041
(rejection); 3 parser unit tests. Filed issue 0066 (pre-existing
match-arm negated-literal phi-width quirk, surfaced not caused here).

Gates: zig build, zig build test, run_examples.sh -> 343 passed,
cross_compile.sh -> 7 passed (also refreshed its stale example names).
2026-06-02 09:23:50 +03:00

44 lines
1.5 KiB
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// Phase 3 step 3.0 (PLAN-FFI.md): `inst.method(args)` on an
// `#objc_class`-typed receiver lowers to `objc_msg_send` with a derived
// selector. This test covers the niladic shape: the sx-side method name
// is used verbatim as the selector (`length` → `length`).
//
// Test pattern mirrors `ffi-objc-call-08-multi-keyword.sx`: synthesize a
// fresh class at runtime via `objc_allocateClassPair` + `class_addMethod`,
// declare the sx-side `#objc_class` against the same name, then invoke
// the DSL form. On macOS this exercises the real Obj-C runtime; on
// other platforms the test skips.
//
// Pre-3.0: the dispatch bails at lower.zig with "method calls on
// 'objc_class' runtime not yet supported (Phase 3/4)". Snapshot captures
// that diagnostic.
#import "modules/std.sx";
#import "modules/compiler.sx";
#import "modules/std/objc.sx";
SxProbeNiladic :: #foreign #objc_class("SxProbeNiladic") {
length :: (self: *Self) -> s32;
}
length_imp :: (self: *void, _cmd: *void) -> s32 callconv(.c) {
42
}
main :: () -> s32 {
inline if OS == .macos {
ns_object := objc_getClass("NSObject".ptr);
cls := objc_allocateClassPair(ns_object, "SxProbeNiladic".ptr, 0);
sel := sel_registerName("length".ptr);
class_addMethod(cls, sel, xx length_imp, "i@:".ptr);
objc_registerClassPair(cls);
inst : *SxProbeNiladic = xx class_createInstance(cls, 0);
n := inst.length();
print("length = {}\n", n);
}
inline if OS != .macos {
print("skipped (not macos)\n");
}
0
}