Files
sx/examples/163-pack-runtime-index.sx
agra 6b5edc77b4 lang: require ':' before a for-loop range cursor
The cursor clause now matches the collection form's ': (capture)' — 'for 0..N: (i)' instead of 'for 0..N (i)'. The colon is required when a cursor is present; the no-cursor form 'for 0..N { }' is unchanged. Updated examples/200, the pack-index doc comment, and the spec.
2026-05-31 10:57:21 +03:00

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// Variadic heterogeneous type packs — Step 2.6: indexing a pack with a
// RUNTIME index is a compile error.
//
// Per locked Decision 1, a pack is comptime-only and has NO runtime
// representation — so `args[i]` is valid only when `i` is a compile-time
// constant (a literal, or an `inline for` cursor). A runtime index (here a
// `while`-loop counter) must produce a clear diagnostic, not the confusing
// "unresolved 'args'" the slice-index fall-through used to give. To walk a
// pack, use `inline for 0..args.len: (i) { ... }`, which unrolls so each
// `args[i]` is a comptime index.
#import "modules/std.sx";
count_anys :: (..$args) -> s64 {
total : s64 = 0;
i : s64 = 0;
while i < args.len {
x : Any = args[i]; // ERROR: runtime index into a comptime-only pack
_ = x;
total = total + 1;
i = i + 1;
}
return total;
}
main :: () -> s32 {
print("{}\n", count_anys(10, "hi", 2.5, true));
return 0;
}