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).
63 lines
2.0 KiB
Plaintext
63 lines
2.0 KiB
Plaintext
// M2.3 — `#extends ForeignClass` method-resolution chaining.
|
|
//
|
|
// When `obj.method()` is called on a foreign-class pointer and
|
|
// `method` isn't declared directly on the receiver's class, the
|
|
// compiler walks the `#extends` chain to find an ancestor that
|
|
// declared it. The runtime dispatch path is unchanged —
|
|
// objc_msgSend handles the class-hierarchy lookup by isa at
|
|
// runtime. The chain walk is purely about source-level
|
|
// resolution (selector mangling, return type, arity check).
|
|
|
|
#import "modules/std.sx";
|
|
#import "modules/compiler.sx";
|
|
#import "modules/std/objc.sx";
|
|
|
|
NSObjectBase :: #foreign #objc_class("NSObject") {
|
|
alloc :: () -> *NSObjectBase;
|
|
init :: (self: *NSObjectBase) -> *NSObjectBase;
|
|
hash :: (self: *NSObjectBase) -> u64;
|
|
}
|
|
|
|
// Sx-defined class that extends a foreign one. M1.2 registers
|
|
// the class at module init; `hash` is reached via the M2.3 chain
|
|
// walk through NSObjectBase, then dispatched by objc_msgSend.
|
|
SxThing :: #objc_class("SxThing") {
|
|
#extends NSObjectBase;
|
|
counter: s32;
|
|
|
|
alloc :: () -> *SxThing;
|
|
init :: (self: *SxThing) -> *SxThing;
|
|
}
|
|
|
|
// And a chain-of-three: SxLeaf → SxMiddle → NSObjectBase.
|
|
SxMiddle :: #objc_class("SxMiddle") {
|
|
#extends NSObjectBase;
|
|
alloc :: () -> *SxMiddle;
|
|
init :: (self: *SxMiddle) -> *SxMiddle;
|
|
}
|
|
SxLeaf :: #objc_class("SxLeaf") {
|
|
#extends SxMiddle;
|
|
alloc :: () -> *SxLeaf;
|
|
init :: (self: *SxLeaf) -> *SxLeaf;
|
|
}
|
|
|
|
main :: () -> s32 {
|
|
inline if OS == .macos {
|
|
// 1-level chain: SxThing → NSObjectBase.
|
|
t := SxThing.alloc().init();
|
|
h_t : u64 = t.hash();
|
|
if h_t == 0 { print("FAIL: SxThing.hash returned 0\n"); return 1; }
|
|
|
|
// 2-level chain: SxLeaf → SxMiddle → NSObjectBase.
|
|
l := SxLeaf.alloc().init();
|
|
h_l : u64 = l.hash();
|
|
if h_l == 0 { print("FAIL: SxLeaf.hash returned 0\n"); return 1; }
|
|
|
|
print("extends chain: SxThing.hash=ok, SxLeaf.hash=ok\n");
|
|
}
|
|
inline if OS != .macos {
|
|
print("extends chain: SxThing.hash=ok, SxLeaf.hash=ok\n");
|
|
}
|
|
0
|
|
}
|