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).
56 lines
1.8 KiB
Plaintext
56 lines
1.8 KiB
Plaintext
// Tuple values: construction, element access, struct-field storage,
|
|
// return, and operators. Regression for the tuple-construction bug where
|
|
// an inferred `:=` tuple literal lowered its element values under the
|
|
// enclosing fn's (narrower) return `target_type`, mismatching the
|
|
// independently-inferred s64 field types and yielding garbage on read.
|
|
|
|
#import "modules/std.sx";
|
|
|
|
Box :: struct { xs: (s32, s32); }
|
|
|
|
swap :: (a: s64, b: s64) -> (s64, s64) { (b, a) }
|
|
fst :: (t: (s64, s64)) -> s64 { t.0 }
|
|
|
|
main :: () -> s32 {
|
|
// Inferred positional tuple + numeric field access.
|
|
pair := (40, 2);
|
|
print("pair {} {}\n", pair.0, pair.1);
|
|
|
|
// Named tuple: named + numeric access.
|
|
named := (x: 10, y: 20);
|
|
print("named {} {} {}\n", named.x, named.0, named.1);
|
|
|
|
// Element into a typed local (access path, not just print).
|
|
a : s64 = pair.0;
|
|
b : s64 = pair.1;
|
|
print("locals {} {}\n", a, b);
|
|
|
|
// Tuple-typed struct field: store a tuple value, read both elements.
|
|
box : Box = ---;
|
|
box.xs = (7, 9);
|
|
print("field {} {}\n", box.xs.0, box.xs.1);
|
|
|
|
// Return a tuple from a function.
|
|
s := swap(1, 2);
|
|
print("ret {} {}\n", s.0, s.1);
|
|
|
|
// Pass a tuple by value.
|
|
print("pass {}\n", fst((11, 22)));
|
|
|
|
// Operators: equality, concatenation, repetition, membership, lex.
|
|
print("eq {}\n", (1, 2) == (1, 2));
|
|
c := (1, 2) + (3, 4);
|
|
print("concat {} {}\n", c.0, c.3);
|
|
r := (1, 2) * 3;
|
|
print("rep {} {}\n", r.0, r.5);
|
|
print("mem {}\n", 3 in (1, 2, 3));
|
|
print("lex {}\n", (1, 2) < (1, 3));
|
|
|
|
// Mixed-size fields: a tuple with both an s64 and a string (16-byte fat
|
|
// pointer). Field types are tracked per-position, so reading each back is
|
|
// typed correctly (s64 prints as a number, string as text).
|
|
mixed := (42, "hi");
|
|
print("mixed {} {}\n", mixed.0, mixed.1);
|
|
0
|
|
}
|