Domain validators¶

A domain-level <validator> lists valid configurations of propositions. Each configuration is a conjunction; the declared configurations are alternatives.

<validator name="DestinationValidity">
  <configuration>
    <proposition predicate="destination" value="karlstad"/>
  </configuration>
  <configuration>
    <proposition predicate="destination" value="gothenburg"/>
  </configuration>
</validator>

name identifies the validator. Tala 31.0.1's XML compiler reads configuration children; DDD JSON represents them as valid_configurations. Each configuration is considered when values exist for all its predicates; one matching configuration accepts the propositions. If none matches, validation rejects the configuration and identifies the validator in the rejection move. This declaration validates domain facts and differs from a Service Interface validator, which calls an external operation.