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).
53 lines
2.1 KiB
Plaintext
53 lines
2.1 KiB
Plaintext
// Phase 1 step 1.8 (PLAN-FFI.md): >16 B non-HFA struct returns
|
|
// through `#objc_call`. AAPCS64 routes these through the indirect-
|
|
// return convention: caller allocates the result slot, passes its
|
|
// pointer in x8 with the `sret(<T>)` attribute, callee writes
|
|
// through it and returns void.
|
|
//
|
|
// Register a runtime-built Obj-C class with a method that returns
|
|
// a fixed `Triple`. The IMP is a plain sx fn (callconv .c) — its
|
|
// sret-shaped lowering already works (Phase 0.3 fix for plain
|
|
// `#foreign` returns). The `#objc_call` dispatch side now produces
|
|
// the matching call shape: `call void @objc_msgSend(ptr sret %slot,
|
|
// ...)` + load. The two halves must agree on the ABI for the
|
|
// round-trip to return the right bytes.
|
|
|
|
#import "modules/std.sx";
|
|
#import "modules/compiler.sx";
|
|
#import "modules/std/objc.sx";
|
|
|
|
Triple :: struct { a: s64; b: s64; c: s64; }
|
|
|
|
// IMP for the runtime-installed method. Obj-C convention: implicit
|
|
// (self, _cmd) prefix, then declared args. Returns the value bytes.
|
|
triple_imp :: (self: *void, _cmd: *void) -> Triple callconv(.c) {
|
|
Triple.{ a = 11, b = 22, c = 33 }
|
|
}
|
|
|
|
main :: () -> s32 {
|
|
inline if OS == .macos {
|
|
// Build the class:
|
|
// @interface SxTripleProbe : NSObject
|
|
// - (Triple)tripleValue;
|
|
// @end
|
|
ns_object := objc_getClass("NSObject".ptr);
|
|
my_cls := objc_allocateClassPair(ns_object, "SxTripleProbe".ptr, 0);
|
|
sel := sel_registerName("tripleValue".ptr);
|
|
// Type encoding: {Triple=qqq}@: → returns 24 B struct of 3 s64,
|
|
// implicit (self: id, _cmd: SEL).
|
|
ok := class_addMethod(my_cls, sel, xx triple_imp, "{Triple=qqq}@:".ptr);
|
|
print("addMethod = {}\n", ok);
|
|
objc_registerClassPair(my_cls);
|
|
|
|
// Call through #objc_call — sret transform applies because
|
|
// Triple is 24 B non-HFA.
|
|
instance := class_createInstance(my_cls, 0);
|
|
t := #objc_call(Triple)(instance, "tripleValue");
|
|
print("triple = ({}, {}, {})\n", t.a, t.b, t.c);
|
|
}
|
|
inline if OS != .macos {
|
|
print("skipped (not macos)\n");
|
|
}
|
|
0
|
|
}
|