pub fn open_traversal(
parent: &mut dyn Kernel,
traversal: Traversal,
) -> Result<TraversalStream, String>Expand description
Open traversal against parent’s current values, on any engine
(engine parity, step 8): the cascaded wires are snapshotted through
the Kernel trait, and the comprehension is evaluated in the
body’s scope, the body’s program with those wires bound, where a
source or predicate resolves every name it can reference and a
tuple’s own elements are layered in front as it is built. Nothing
here needs the opening kernel beyond the snapshot.