Module iterator_state 

Iterator-state carrier — the kinded redesign of the deleted heap_value::IteratorState / IteratorTransform ValueWord-shaped enums.

ADR-006 §2.7.16 / Q17 (W13-iterator-state, 2026-05-10). Lazy iterator pipelines are represented as a plain typed Arc<IteratorState> whose payload is (a) a typed IteratorSource over an existing Arc<T>-backed collection and (b) an ordered list of typed IteratorTransform stages. Each transform that takes a callback stores the closure carrier as Arc<HeapValue> directly per ADR-006 §2.7.11 / Q12 — the value-call ABI is kind-aware via KindedSlot at the dispatch boundary, so a stored closure flows back into vm.call_value_immediate_nb as a fresh KindedSlot { kind: Ptr(HeapKind::Closure), .. } carrier whose share is bumped from the stored Arc<HeapValue>.

Slot bits for an Iterator-labeled slot are Arc::into_raw(Arc<IteratorState>) as u64 (mirror of §2.7.9 FilterExpr / §2.7.13 Reference — NOT a Box::into_raw(Box<HeapValue>) wrap). clone_with_kind / drop_with_kind retain/release Arc<IteratorState> directly via the HeapKind::Iterator dispatch arm. slot.as_heap_value() IS valid on Iterator-labeled bits — unlike FilterExpr/Reference, HeapValue::Iterator(Arc<IteratorState>) participates in the §2.3 typed-Arc payload pattern, and the dispatch shell may recover the state via the canonical slot.as_heap_value() → HeapValue::Iterator match (the iterator method handlers use this path).

No new dispatch surface is introduced — clone_with_kind / drop_with_kind / KindedSlot::clone / KindedSlot::drop / TypedObjectStorage::drop / SharedCell::drop each grow one new arm (the same shape as the §2.7.9 FilterExpr / §2.7.12 SharedCell / §2.7.13 Reference precedents).

Structs

IteratorState

Lazy iterator carrier. Stored on the heap as Arc<IteratorState>; the runtime slot label is NativeKind::Ptr(HeapKind::Iterator).

Enums

IteratorSource

Source backing a lazy iterator pipeline. Each variant holds a typed Arc<T> over an existing collection so iteration shares the receiver’s storage without a deep copy.

IteratorTransform

Lazy transform stage in an iterator pipeline. Each closure-bearing variant stores the callback as Arc<HeapValue> per ADR-006 §2.3 / §2.7.11 — the same share carrier the op_call_value / call_value_immediate_nb path consumes (the slot bits at the §2.7.7 stack tier are Arc::into_raw(Arc<HeapValue>) pointing to a HeapValue::ClosureRaw(OwnedClosureBlock) arm; the iterator-state stash here keeps an extra share alive for the iterator’s lifetime).