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).
36 lines
1.1 KiB
Plaintext
36 lines
1.1 KiB
Plaintext
// Phase 3 step 3.0: one-arg selector mangling. `addObject(o)` derives
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// `addObject:` — the sx method name becomes the keyword, a single
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// trailing `:` for the single arg. Selector arity (count of `:`) must
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// equal sx-side arity excluding self.
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//
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// Pre-3.0: bails at lower.zig with the Phase 3/4 diagnostic.
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#import "modules/std.sx";
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#import "modules/compiler.sx";
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#import "modules/std/objc.sx";
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SxProbeOneArg :: #foreign #objc_class("SxProbeOneArg") {
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addObject :: (self: *Self, val: s32) -> s32;
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}
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addObject_imp :: (self: *void, _cmd: *void, val: s32) -> s32 callconv(.c) {
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val * 2
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}
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main :: () -> s32 {
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inline if OS == .macos {
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ns_object := objc_getClass("NSObject".ptr);
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cls := objc_allocateClassPair(ns_object, "SxProbeOneArg".ptr, 0);
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sel := sel_registerName("addObject:".ptr);
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class_addMethod(cls, sel, xx addObject_imp, "i@:i".ptr);
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objc_registerClassPair(cls);
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inst : *SxProbeOneArg = xx class_createInstance(cls, 0);
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n := inst.addObject(21);
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print("addObject(21) = {}\n", 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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