109 urn:lsid:arphahub.com:pub:3dc5f44e-8666-58db-bc76-a455210e8891 JUCS - Journal of Universal Computer Science jucs 0948-695X 0948-6968 Journal of Universal Computer Science 10.3217/jucs-014-20-3370 29248 Research Article D.1 - PROGRAMMING TECHNIQUES D.3.3 - Language Constructs and Features Custom Specializers in Object-Oriented Lisp Newton Jim jimka@cadence.com 1 Rhodes Christophe 2 Cadence Design Systems, Feldkirchen, Germany Cadence Design Systems Feldkirchen Germany University of London New Cross, London, United Kingdom University of London New Cross London United Kingdom

Corresponding author: Jim Newton (jimka@cadence.com).

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2008 28 11 2008 14 20 3370 3388 DAC0E4B9-3045-5AEA-A6FC-079383CF88F1 7000559 Jim Newton, Christophe Rhodes This article is freely available under the J.UCS Open Content License.

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.