82bdcd634a
Per locked Decision 1 a pack is comptime-only with no runtime value, so xs[i]
is valid only for a comptime index. lowerIndexExpr now emits a clear error
("pack <p> must be indexed by a compile-time constant ...") for a runtime
index, instead of the confusing "unresolved <p>" the slice-index fall-through
produced. diagPackIndexOOB switched from int-literal-only to comptimeIndexOf so
an inline-for cursor that goes out of bounds is also caught.
Repurposed examples/163-pack-runtime-index.sx (was aspirational: expected
runtime indexing to materialise a []Any slice and print 4, contradicting
Decision 1) into the runtime-index error test. Comptime + OOB cases already
covered by examples/199/200/161. 236 examples + unit green.
30 lines
973 B
Plaintext
30 lines
973 B
Plaintext
// Variadic heterogeneous type packs — Step 2.6: indexing a pack with a
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// RUNTIME index is a compile error.
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//
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// Per locked Decision 1, a pack is comptime-only and has NO runtime
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// representation — so `args[i]` is valid only when `i` is a compile-time
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// constant (a literal, or an `inline for` cursor). A runtime index (here a
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// `while`-loop counter) must produce a clear diagnostic, not the confusing
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// "unresolved 'args'" the slice-index fall-through used to give. To walk a
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// pack, use `inline for 0..args.len (i) { ... }`, which unrolls so each
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// `args[i]` is a comptime index.
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#import "modules/std.sx";
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count_anys :: (..$args) -> s64 {
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total : s64 = 0;
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i : s64 = 0;
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while i < args.len {
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x : Any = args[i]; // ERROR: runtime index into a comptime-only pack
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_ = x;
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total = total + 1;
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i = i + 1;
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}
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return total;
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}
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main :: () -> s32 {
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print("{}\n", count_anys(10, "hi", 2.5, true));
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return 0;
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}
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