Once¶

Definition¶

<once>
...
</once>

A part of a dialogue plan, consisting of a sequence of plan items, which is run only once.

Parents¶

• <plan>

Children¶

• <assume_issue>
• <assume_shared>
• <assume_system_belief>
• <bind>
• <findout>
• <forget>
• <forget_all>
• <get_done>
• <if>
• <inform>
• <invoke_service_action>
• <invoke_service_query>
• <jumpto>
• <log>
• <raise>
• <signal_action_completion>
• <signal_action_failure>

Behaviour¶

The plan items inside this element will be run only once. After the "once" element has been run, TDM will keep track of it and make sure that it isn't run again until the session is restarted or until a <forget_all> item is executed.

There is nothing that prohibits using the once element inside another once element, but it is not intended, and the consequences are unknown.

Examples¶

Plan for asking a sequence of questions and getting the price of a trip.¶

<plan>
  <once>
    <inform>
      <proposition predicate="info" value="Listen carefully! I will say this only once!"/>
    </inform>
  </once>
  <inform>
    <proposition predicate="other_info" value="I will say this any time I get the chance!"/>
  </inform>
</plan>