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).
62 lines
1.6 KiB
Plaintext
Executable File
62 lines
1.6 KiB
Plaintext
Executable File
#import "modules/std.sx";
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// --- State(T) — a handle to persistent storage ---
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State :: struct ($T: Type) {
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ptr: *T;
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get :: (self: State(T)) -> T { self.ptr.* }
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set :: (self: State(T), val: T) { self.ptr.* = val; }
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}
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// --- StateEntry — type-erased storage ---
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StateEntry :: struct {
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id: s64;
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data: [*]u8;
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size: s64;
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generation: s64;
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}
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// --- StateStore — manages persistent state ---
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StateStore :: struct {
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entries: List(StateEntry);
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current_generation: s64;
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parent_allocator: Allocator;
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init :: (self: *StateStore) {
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self.entries = List(StateEntry).{};
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self.current_generation = 0;
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self.parent_allocator = context.allocator;
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}
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get_or_create :: (self: *StateStore, id: s64, $T: Type, default: T) -> State(T) {
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// Search for existing entry
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i : s64 = 0;
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while i < self.entries.len {
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if self.entries.items[i].id == id {
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self.entries.items[i].generation = self.current_generation;
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return State(T).{ ptr = xx self.entries.items[i].data };
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}
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i += 1;
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}
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// Create new entry
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data : [*]u8 = xx self.parent_allocator.alloc(size_of(T));
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memcpy(data, @default, size_of(T));
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self.entries.append(.{
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id = id,
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data = data,
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size = size_of(T),
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generation = self.current_generation
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}, self.parent_allocator);
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State(T).{ ptr = xx data }
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}
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next_frame :: (self: *StateStore) {
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self.current_generation += 1;
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}
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}
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