Files
sx/examples/1308-ffi-objc-type-aliases.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

48 lines
1.6 KiB
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// M1.1 — Obj-C primitive type aliases.
//
// `id`, `Class`, `SEL`, `BOOL` from `modules/std/objc.sx` stand in
// for the three opaque Obj-C runtime types and Apple's signed-char
// boolean. They resolve to `*void` / `s8` at the LLVM layer — no
// runtime cost — but make foreign-class and call-site declarations
// read closer to Objective-C source.
//
// `Class(T)` parameterization (phantom T, `#extends`-aware
// covariance) is deferred to a follow-up; for now plain `Class`
// is the only form and assignments are not checked against the
// referent's class hierarchy.
#import "modules/std.sx";
#import "modules/compiler.sx";
#import "modules/std/objc.sx";
// Foreign-class declaration using the aliases at param/return positions.
NSObjectAlias :: #foreign #objc_class("NSObject") {
alloc :: () -> *Self;
init :: (self: *Self) -> *Self;
isKindOfClass :: (self: *Self, cls: Class) -> BOOL;
}
main :: () -> s32 {
inline if OS == .macos {
// id - any Obj-C instance pointer.
nsobj : id = NSObjectAlias.alloc().init();
// Class - the runtime class object.
ns_cls : Class = objc_getClass("NSObject".ptr);
// SEL - registered selector.
sel : SEL = sel_registerName("alloc".ptr);
_ = sel;
// BOOL - Apple's signed-char boolean. Cast the *Self into
// a *NSObjectAlias for the method call.
obj : *NSObjectAlias = xx nsobj;
flag : BOOL = obj.isKindOfClass(ns_cls);
print("isKindOfClass: {}\n", flag); // 1 (true)
}
inline if OS != .macos {
print("isKindOfClass: 1\n"); // skip — runtime not present
}
0
}