Cannot use event as action (Dezyne Reference Manual)

11.4.1 Cannot use event as action

In an interface this indicates the an in-event–that can only be used as a trigger—is used as an action in the imperative body of an on.

interface interface_trigger_used_as_action
{
  in void hello ();
  behavior
  {
    on hello: hello;
  }
}

This results in the following error message:

interface-trigger-used-as-action.dzn:6:15: error: cannot use in-event
    `hello' as action
interface-trigger-used-as-action.dzn:3:3: info: event `hello' defined
    here

in a component this indicates that either it is an in-event of a provides interface, or an out-event of a requires interface that is used as an action in the imperative body of an on.

interface ihello
{
  in void hello ();
  out void world ();
  behavior {on hello:world;}
}

component component_trigger_used_as_action
{
  provides ihello p;
  requires ihello r;
  behavior
  {
    on p.hello ():
    {
      p.hello ();
      r.world ();
    }
  }
}

This results in the following error messages:

component-trigger-used-as-action.dzn:16:7: error: cannot use provides
    in-event `hello' as action
component-trigger-used-as-action.dzn:10:3: info: port `p' defined here
component-trigger-used-as-action.dzn:3:3: info: event `hello' defined
    here
component-trigger-used-as-action.dzn:17:7: error: cannot use requires
    out-event `world' as action
component-trigger-used-as-action.dzn:11:3: info: port `r' defined here
component-trigger-used-as-action.dzn:4:3: info: event `world' defined
    here