An empty expression is not an error
The rule
Normative: this is the rule
- An empty expression is valid: it passes validation, and it produces a defined result rather than a failure.
- A mapper output whose expression is empty is null, whatever the engine.
- An extractor whose path is empty returns its input unchanged, reports success, and reports no match.
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-3 · changed in spec 1.0