Ontolingua [] is primarily a translation and analysis tool for ontologies, but its most recent version (4.0) includes a little frame system. This means that one can write portable KIF ontologies and access them as knowledge bases using GFP. From the Ontolingua user's point of view, there is a target implementations system called :generic-frame. Making this the current implementation (i.e., by saying (ol:in-implementation :generic-frame)) causes ontolingua to store ontologies in the frame system data structures.
The Ontolingua generic-frame system supports the full range of GFP functionality. Although it is complete, it is slow.
The behaviors supported by the Ontolingua back end are as follows:
Use KB class ontolingua:generic-frame to build Ontolingua KBs.