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).
48 lines
1.0 KiB
Plaintext
48 lines
1.0 KiB
Plaintext
#import "modules/std.sx";
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Point :: struct {
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x: s32;
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y: s32;
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}
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// Print all arguments — accepts any type, dispatches via type-switch
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print_any :: (..args: []Any) {
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for args: (it) {
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type := type_of(it);
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if type == {
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case int: out(int_to_string(cast(s32) it));
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case string: out(cast(string) it);
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case bool: out(bool_to_string(cast(bool) it));
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case float: out(float_to_string(cast(f64) it));
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case Point: {
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p := cast(Point) it;
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out("(");
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out(int_to_string(p.x));
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out(",");
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out(int_to_string(p.y));
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out(")");
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}
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}
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out(" ");
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}
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out("\n");
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}
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count :: (..args: []Any) -> s32 {
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args.len
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}
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main :: () -> s32 {
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print_any(42, "hello", true, 3.14);
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// Test with struct
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p := Point.{ x=10, y=20 };
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print_any("point:", p, 99);
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// Test count
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out(int_to_string(count(1, 2, 3)));
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out("\n");
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0
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}
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