摘要：We describe in this paper the implementation and use of custom specializers in
two current dialects of Lisp: Skill and Common Lisp. We motivate the need for
such specializers by appealing to clarity of expression, referring to experience
in existing industrial applications. We discuss the implementation details of
such user-defined specializers in both dialects of Lisp, detailing open problems
with those implementations, and we sketch ideas for solving them.
关键词：Lisp, Metaobject Protocol, Specializer, generic function
