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).
51 lines
855 B
Plaintext
51 lines
855 B
Plaintext
#import "modules/std.sx";
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sumOf10 :: () -> s32 {
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i:= 1;
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s:=0;
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while i <= 10 {
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s+=i;
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i+=1;
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}
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s
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}
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someSum :: #run sumOf10();
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main :: () {
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// Basic while loop: count to 5
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i := 0;
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while i < 5 {
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i += 1;
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}
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print("count: {}\n", i);
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// While with break
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x := 1;
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while x < 100 {
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if x == 12 {
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break;
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}
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x += 1;
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}
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print("break at: {}\n", x);
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// While with continue: sum odd numbers 1-9
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sum := 0;
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j := 0;
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while j < 10 {
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j += 1;
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// Skip even numbers
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if j == 2 { continue; }
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if j == 4 { continue; }
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if j == 6 { continue; }
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if j == 8 { continue; }
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if j == 10 { continue; }
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sum += j;
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}
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print("sum of odd 1-9: {}\n", sum);
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print("sum {}", someSum);
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}
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