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).
107 lines
2.4 KiB
Plaintext
107 lines
2.4 KiB
Plaintext
#import "modules/std.sx";
|
|
#import "modules/math/math.sx";
|
|
#import "modules/compiler.sx";
|
|
#import "modules/test.sx";
|
|
pkg :: #import "modules/testpkg";
|
|
|
|
Perms :: enum flags { read; write; execute; }
|
|
|
|
WindowFlags :: enum flags u32 { vsync :: 64; resizable :: 4; hidden :: 128; }
|
|
|
|
// --- Top-level functions ---
|
|
|
|
main :: () {
|
|
|
|
// ========================================================
|
|
// 9. FLAGS
|
|
// ========================================================
|
|
print("=== 9. Flags ===\n");
|
|
|
|
// Combine flags
|
|
perm : Perms = .read | .write;
|
|
print("flags: {}\n", perm);
|
|
|
|
// Test flag
|
|
if perm & .read { print("has-read: yes\n"); }
|
|
if perm & .execute { print("has-exec: yes\n"); }
|
|
|
|
// Test flag negative
|
|
pt : Perms = .write;
|
|
if pt & .read {
|
|
print("flags-neg: has-read\n");
|
|
} else {
|
|
print("flags-neg: no-read\n");
|
|
}
|
|
|
|
// Single flag
|
|
ps : Perms = .execute;
|
|
print("flags-single: {}\n", ps);
|
|
|
|
// All flags
|
|
pall : Perms = .read | .write | .execute;
|
|
print("flags-all: {}\n", pall);
|
|
|
|
// Cast to int
|
|
print("flags-raw: {}\n", cast(s64) perm);
|
|
|
|
// Flags with explicit values
|
|
wf : WindowFlags = .vsync | .resizable;
|
|
print("flags-explicit: {}\n", wf);
|
|
print("flags-explicit-raw: {}\n", cast(s64) wf);
|
|
|
|
// --- Multi-target assignment (swap) ---
|
|
print("--- swap ---\n");
|
|
|
|
// Variable swap
|
|
{
|
|
sa := 10;
|
|
sb := 20;
|
|
sa, sb = sb, sa;
|
|
print("var swap: {} {}\n", sa, sb);
|
|
}
|
|
|
|
// Array element swap
|
|
{
|
|
sarr : [3]s64 = .[1, 2, 3];
|
|
sarr[0], sarr[2] = sarr[2], sarr[0];
|
|
print("arr swap: {} {}\n", sarr[0], sarr[2]);
|
|
}
|
|
|
|
// 3-way rotation
|
|
{
|
|
ra := 1;
|
|
rb := 2;
|
|
rc := 3;
|
|
ra, rb, rc = rc, ra, rb;
|
|
print("3-way: {} {} {}\n", ra, rb, rc);
|
|
}
|
|
|
|
// --- Tuple destructuring ---
|
|
print("--- destructure ---\n");
|
|
|
|
// Basic tuple destructuring
|
|
{
|
|
da, db := (10, 20);
|
|
print("basic: {} {}\n", da, db);
|
|
}
|
|
|
|
// Destructure from function return
|
|
{
|
|
dswap :: (a: s64, b: s64) -> (s64, s64) { (b, a) }
|
|
dx, dy := dswap(1, 2);
|
|
print("fn: {} {}\n", dx, dy);
|
|
}
|
|
|
|
// Discard with _
|
|
{
|
|
_, dsecond := (100, 200);
|
|
print("discard: {}\n", dsecond);
|
|
}
|
|
|
|
// Three elements
|
|
{
|
|
da3, db3, dc3 := (1, 2, 3);
|
|
print("triple: {} {} {}\n", da3, db3, dc3);
|
|
}
|
|
}
|