parallel event in a state

[emclab]

Here is an example from [Geekq/workflow][1] which we are using in our rails app:

workflow do
state :new do
event :submit, :transitions_to => :awaiting_review
end
state :awaiting_review do
event :review, :transitions_to => :being_reviewed
end
state :being_reviewed do
event :accept, :transitions_to => :accepted
event :reject, :transitions_to => :rejected
end
state :accepted
state :rejected
end

The events in a state are mutually exclusive. For example, only one of events accept and reject is going to happen. How to add a parallel event like send_bill, in :awaiting_review? Both send bill and review are going to happen at the same time. Here is what we would like to have (parallel_event is NOT Geekq/workflow definition):

state :awaiting_review do
  parallel_event :review, :transitions_to => :being_reviewed
  parallel_event :send_bill, :transitions_to => :being_reviewed
end

[emclab]

We end up keeping transitions_to the same state if the other paralle event hasn't been fired or to next state if all other parallel events have been fired. Here is an example for one event:

state :awaiting_review do
event :review, :transitions_to => :awaiting_review,
:if => proc {other_events_not_filed}
event :review, :transitions_to => :next_state,
:if => proc {other_event_did_filed}
end