bdd0e96d78
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).
43 lines
1.6 KiB
Plaintext
43 lines
1.6 KiB
Plaintext
// Phase 1 step 1.4 (PLAN-FFI.md): multiple `#objc_call` sites
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// with the same selector. Today (after 1.3) each site emits its
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// own `call @sel_registerName(<"init">)`; the actual SEL handle
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// is recomputed per call.
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//
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// 1.5 lands selector interning: one static `SEL` global per
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// unique selector string (named `OBJC_SELECTOR_REFERENCES_init`,
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// matching clang's convention) populated once via the runtime
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// at module init. Per call site becomes a single load.
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//
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// Runtime behavior is unchanged before vs. after 1.5; the
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// improvement is visible in `sx ir` only. The IR snapshot at
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// `tests/expected/ffi-objc-call-03-selector-sharing.ir` locks
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// in today's shape (4 `call ptr @sel_registerName` instructions,
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// one per call site). After 1.5 lands selector interning, the
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// snapshot updates to ≤2 (one per unique selector string) plus
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// a static `@OBJC_SELECTOR_REFERENCES_<sel>` global and loads at
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// the call sites.
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#import "modules/std.sx";
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#import "modules/compiler.sx";
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main :: () -> s32 {
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inline if OS == .macos {
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// Three calls, same selector, same nil receiver. Today these
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// emit three `sel_registerName("init")` calls. After 1.5 the
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// emit collapses to one (cached SEL global).
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#objc_call(void)(null, "init");
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#objc_call(void)(null, "init");
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#objc_call(void)(null, "init");
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// A different selector — should remain distinct after 1.5
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// (one cached SEL per unique string, not per call site).
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#objc_call(void)(null, "release");
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print("ok\n");
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}
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inline if OS != .macos {
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print("skipped (not macos)\n");
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}
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0
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}
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