CLOSe to the edge? Advanced Object-Oriented Techniques in the Representation of Musical Knowledge Peter Desain, Henkjan Honing Abstract: CLOSe to the edge? Advanced object­oriented techniques in the representation of musical knowledge Peter Desain, Henkjan Honing The modeling of knowledge about musical expression asks for quite some flexibility during the design process and the availability of high­level abstractions to represent the complex concepts and their interactions in this domain successfully. One would expect, because of the enthusiastic claims made in the literature on object­oriented programming, that such an approach would be ideal for this task. This paper describes some aspects of CLOS, an modern object­oriented language that indeed provides some advanced construct that proved useful in the design and maintenance of a complex system for the manipulation of expression in music. However, some of the mechanisms should be used with care to stay far from the edge beyond which programs become too complex to grasp.