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
1.3 KiB
Plaintext
43 lines
1.3 KiB
Plaintext
// M1.2 A.2c / A.3 — instance-method body lowering on sx-defined
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// `#objc_class`.
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//
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// The Obj-C runtime invokes class methods via the IMP pointers
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// wired up in M1.2 A.4. No sx-side call path drives lazy lowering,
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// so the eager pass `lowerObjcDefinedClassMethods` walks the
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// `objc_defined_class_cache` and force-lowers every bodied method
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// after Pass 1 finishes.
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//
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// `*Self` substitution (A.2b) routes the param's pointee type to
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// the hidden state-struct `__<ClassName>State`. `self.counter`
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// then resolves as a plain struct field access — A.3's "free if
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// types align". The IR snapshot pins the round-trip:
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//
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// define internal void @SxFoo.bump(ptr __sx_ctx, ptr self) {
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// %gep = getelementptr inbounds { i32 }, ptr %self, 0, 0
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// %v = load i32, ptr %gep
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// %inc = add i32 %v, 1
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// store i32 %inc, ptr %gep
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// ret void
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// }
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//
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// IMP-trampoline emission (the C-ABI shim that the Obj-C runtime
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// calls and that reads the `__sx_state` ivar) lands separately
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// in M1.2 A.4 alongside class-pair init. Runtime dispatch
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// (M1.2 A.7) stays gated until then.
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#import "modules/std.sx";
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#import "modules/compiler.sx";
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SxFoo :: #objc_class("SxFoo") {
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counter: s32;
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bump :: (self: *Self) {
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self.counter += 1;
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}
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}
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main :: () -> s32 {
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print("compiled\n");
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0
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}
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