-- `.?field` on a present record with the field missing now returns nil instead
-- of erroring ILO-R005. Lets you walk heterogeneous JSON (NVD CVE metrics,
-- GitHub events, Stripe payloads) without an outer jdmp+jpth fallback per
-- optional probe. Static-typed records still error on typo via the verifier.
miss j:t>R t t;r=jpar! j;~fmt "{}" r.?cvssMetricV31
hit j:t>R n t;r=jpar! j;r.?present
chain j:t>R t t;r=jpar! j;~fmt "{}" r.?outer.?inner
nilobj j:t>R t t;r=jpar! j;v=r.?missing;~fmt "{}" v.?anything
-- run: miss {"cvssMetricV2":[]}
-- out: nil
-- run: hit {"present":42}
-- out: 42
-- run: chain {"outer":{"inner":"x"}}
-- out: x
-- run: chain {"other":1}
-- out: nil
-- run: nilobj {"a":1}
-- out: nil