Easy definition of new facets in the frame-based language Objlog

This article aims at presenting a method that allows to extend frame-based languages at the level of their facets, in the framework of a language call ed Objlog+. First, we describe the different methods classically used to cr eate new facets and show their limitations. We then propose our facet defin ition method which keeps them their status of descriptive elements within s lots. Its fundamental principle consists in representing every facet by mea ns of a frame which contains its properties as well as the knowledge allowi ng our language to manage the control structure of this facet automatically at the moment one of its occurrences within a frame slot is accessed. For that purpose, the facet notion has been first analyzed systematically in or der to extract its main characteristics. (C) 2001 Elsevier Science B.V. All rights reserved.