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).
50 lines
2.2 KiB
Plaintext
50 lines
2.2 KiB
Plaintext
// Phase 0 baseline (PLAN-FFI.md step 0.5): the three shapes that
|
|
// actually appear at the sx ↔ C boundary today:
|
|
//
|
|
// 1. Null-terminated `[:0]u8` — passed by `.ptr` to a `const char *`.
|
|
// 2. Raw byte buffer `[*]u8` — pointer + explicit length.
|
|
// 3. sx `string` value — coerceArg's "fat-pointer decay" branch
|
|
// pulls `.ptr` automatically for `*u8`/
|
|
// `[:0]u8` params (string is `{ptr, len}`).
|
|
// 4. Pointer return from C — round-trips back as `[*]u8` / `*u8`.
|
|
|
|
#import "modules/std.sx";
|
|
|
|
#import c {
|
|
#source "1213-ffi-05-string-args.c";
|
|
};
|
|
|
|
ffi_strlen :: (s: [:0]u8) -> s32 #foreign;
|
|
ffi_first_byte :: (s: [:0]u8) -> s32 #foreign;
|
|
ffi_sum_bytes :: (buf: [*]u8, len: s32) -> s32 #foreign;
|
|
ffi_write_byte :: (buf: [*]u8, idx: s32, v: u8) -> void #foreign;
|
|
ffi_static_greeting :: () -> [*]u8 #foreign;
|
|
|
|
main :: () -> s32 {
|
|
// ── [:0]u8 null-terminated literal ─────────────────────────────
|
|
msg : [:0]u8 = "hello";
|
|
print("strlen(\"hello\") = {}\n", ffi_strlen(msg));
|
|
print("first_byte = {}\n", ffi_first_byte(msg));
|
|
|
|
// ── sx `string` → C `const char *` (slice-decay through coerceArg) ─
|
|
s : string = "sx string here";
|
|
print("strlen(sx string) = {}\n", ffi_strlen(xx s.ptr));
|
|
|
|
// ── [*]u8 raw buffer + length ──────────────────────────────────
|
|
bytes : [4]u8 = .[10, 20, 30, 40];
|
|
bp : [*]u8 = xx @bytes[0];
|
|
print("sum_bytes([10,20,30,40]) = {}\n", ffi_sum_bytes(bp, 4));
|
|
|
|
// ── Mutate buffer via C, read back from sx ─────────────────────
|
|
ffi_write_byte(bp, 1, 99);
|
|
print("bytes[1] after write = {}\n", bytes[1]);
|
|
|
|
// ── C returns a static string pointer; read it byte-by-byte ────
|
|
g := ffi_static_greeting();
|
|
n := ffi_strlen(xx g);
|
|
print("static greeting len = {}\n", n);
|
|
print("static greeting [0] = {}\n", g[0]);
|
|
|
|
0
|
|
}
|