Multi-Method Dispatch Using Single-Receiver Projections

A new technique for multi-method dispatch, called Single-Receiver Projections and abbreviated SRP, is presented. It operates by performing projections onto single-receiver dispatch tables, and thus benefits from existing research into single-receiver dispatch techniques. It provides method dispatch in O(k), where k is the arity of the method. Unlike existing multi-method dispatch techniques, it also maintains the set of all applicable methods. This extra information allows SRP to support languages like CLOS that use next-method. SRP is also highly incremental in nature, so it is well-suited for languages that require separate compilation and languages that allow methods and classes to be added at run-time. SRP uses less data-structure memory than all existing multi-method techniques and has the second fastest dispatch time. Furthermore, if the other techniques are extended to support all applicable methods, SRP becomes the fastest dispatch techniques.