A null extraction is a miss, not a failure
Extraction engines cannot tell a stored null from no match at all, so the extractor treats both the same way, and only null, never a falsy value.
The rule
Normative: this is the rule
- An extraction that evaluates cleanly and yields null is a miss: the configured default is delivered, the extractor reports success as false (meaning no non-null match was found), and the node succeeds.
- Only null is a miss; false, zero and the empty string are delivered as found.
Rule identifiers are permanent and are never renumbered. Each implementation publishes its own standing against these rules; this specification does not.spec 1.0-draft · LANG-24 · changed in spec 1.0