Never replies to its parent expression. Simply applies its first child, if any, and just sits there.

When cancelled, cancels its child (if any).

In this example, the reminding sequence never replies to the concurrence. The concurrence is only over when "alfred" replies.

  Ruote.process_definition do
    concurrence :count => 1 do
      alfred
      lose do
        sequence do
          wait '2d'
          send_reminder_to_alfred
          wait '2h'
          send_alarm_to_boss
        end
      end
    end
  end

Maybe shorter :

  Ruote.process_definition do
    concurrence :count => 1 do
      alfred
      sequence do
        wait '2d'
        send_reminder_to_alfred
        wait '2h'
        send_alarm_to_boss
        lose
      end
    end
  end

‘lose’ on its own acts like a dead-end.

the :lose attribute

Every expression understands the ‘lose’ attribute :

  Ruote.process_definition do
    concurrence :count => 1 do
      alfred
      sequence :lose => true do
        wait '2d'
        send_reminder_to_alfred
        wait '2h'
        send_alarm_to_boss
      end
    end
  end

Probably produces definitions more compact than when using the ‘lose’ expression.

multi lose

Losing multiple children:

  lose do
    alice :task => 'take out garbage'
    bob :task => 'clean living room'
  end

will trigger alice‘s and bob‘s tasks together. The lose expression will never reply, unless cancelled (in which case alice and bob task get cancelled as well).

forget vs lose vs flank

forget : replies to parent expression immediately, is not cancellable (not reachable).

lose : never replies to the parent expression, is cancellable.

flank : immediately replies to the parent expression, is cancellable.