Need to implement dominance rules..

[davidrpugh]

...need to allow for the possibility that ask or bid orders might be rejected unless they improve upon the current best ask or bid limit prices. In the literature this property is typically referred to as a price improvement or spread reduction rule.

[davidrpugh]

Dominance rules

After reading Wellman and Walsh I think we need to implement a hierarchy of dominance rules...

Base trait would be a mixin called DominanceRule...

trait DominanceRule[A <: AskOrder with Persistent, B <: BidOrder with Persistent] {
  this: AuctionLike[A, B] =>

  def place(order: A): Either[Reject, Accept]

  def place(order: B): Either[Reject, Accept]
 
}

...the way I have sketched it above, each DominanceRule would need to provide a specific implementation of the place(order: ???): Either[Reject, Accept] methods. Examples...

• an AscendingRule requiring that an acceptable Order be superior to an existing order issued by the same agent.
• a DescendingRule requiring that an acceptable Order be inferior to an existing order issued by the same agent.

...note that these rules implicitly assume that auction has a mechanism for identifying which orders were issued by a particular agent. That functionality exists in the current implementation but is not fast (i.e., would be O(n) operation).

"Beat-the-Quote" dominance rules

Also need to define dominance rules that impose restrictions on acceptable orders based on the current best buy/sell orders. In addition to analogous versions of the ascending and descending rules, we should also implement a SpreadReductionRule that imposes an AscendingRule on BidOrder and a DescendingRule on AskOrder.