Function structural_walk

pub fn structural_walk<'input, R, M, H>(
    root: R,
    walker: H,
    order: WalkOrder,
) -> Result<Option<VisitInterrupt>>
where
    H: IntoWalker<M>,
    R: Into<AnyView<'input>>,

Walk root with an observer, the Rust analog of C++ StructuralWalk<order>(root, callbacks...).

walker is anything implementing IntoWalker: a &mut reference to a stateful Dispatcher walker (#[dispatch(walk)]), a bare closure in any WalkChainLink shape (catch-all AnyView<'_>, typed, or node, with an optional trailing DefRegionKind), or a tuple of such callbacks tried in order — the C++ callback overloads and variadic chain. Callback views cannot escape their invocation; retain an Any explicitly when a value must outlive the callback:

use tvm_ffi::{structural_walk, AnyView, WalkOrder, WalkResult};
let mut retained: Option<AnyView<'static>> = None;
structural_walk(&1_i64, |value: AnyView<'_>| {
    retained = Some(value);
    WalkResult::Advance
}, WalkOrder::PreOrder).unwrap();

The walker owns recursion: the handler runs once per value, before or after the value’s children according to order, and steers traversal through the returned WalkResult.