Is also an open source. Its rule language is based on Logic programming as see in the follwing snippet:

exceptionAlarm(startAssignment(DeliveryRequestId,StoreId,ToCoordinates,DeliveryTime),Time):-
delivery_request_enriched(DeliveryRequestId,StoreId,ToCoordinates,DeliveryTime,_MinRank) where (start_assignment_time(Time)). % exceptionAlarm does not consume "delivery_request_enriched"
print_trigger(startAssignment/4).

% The assignment is either an automatic or a manual process, depending on the store's preference.
% start_automaticAssignment/4
start_automaticAssignment(DeliveryRequestId,StoreId,ToCoordinates,DeliveryTime):-
startAssignment(DeliveryRequestId,StoreId,ToCoordinates,DeliveryTime) where store_record(StoreId,_MinRank,automatic).
print_trigger(start_automaticAssignment/4).

% If the process is automatic then the first bidder among the selected drivers wins the bid.
% The pickup time and delivery time are set and the Assignment event is sent to the driver.
% assignment/6
% assignment(+DeliveryRequestId,+StoreId,+ToCoordinates,+DeliveryTime,+DriverId,+ScheduledPickupTime)

consumable_pick_first(DeliveryRequestId,StoreId,ToCoordinates,DeliveryTime,MinRank):-
delivery_request_enriched(DeliveryRequestId,StoreId,ToCoordinates,DeliveryTime,MinRank) where store_record(StoreId,_MinRank,automatic).
print_trigger(consumable_pick_first/5).

assignment(DeliveryRequestId,StoreId,ToCoordinates,DeliveryTime,DriverId,ScheduledPickupTime):-
((consumable_pick_first(DeliveryRequestId,StoreId,ToCoordinates,DeliveryTime,MinRank) seq
delivery_bid(DeliveryRequestId,DriverId,CurrentCoordinates,ScheduledPickupTime) ) seq
start_automaticAssignment(DeliveryRequestId,StoreId,ToCoordinates,DeliveryTime)).
% ) fnot no_bid_alert(DeliveryRequestId) % this line can be added in the code to specify that no bids are accepted after timeout (it's not addresed in the specification)
% we do phase 5 separatelly as different events to show the different phase, but it can also be done in this step
%where ( ScheduledPickupTime=datime(Y,M,D,_,_,_), incCounter(assignments(DriverId,date(Y,M,D))), counter(assignments(DriverId,date(Y,M,D)),Count), write(Count),nl).
print_trigger(assignment/6).