  The Gisela framework for declarative programming was developed with the
specific aim of providing a tool that would be useful for knowledge
representation and reasoning within real-world applications. To achieve this, a
complete integration into an object-oriented application development
environment was used. The framework and methodology developed provide two
alternative application programming interfaces (APIs): Programming using
objects or programming using a traditional equational declarative style. In
addition to providing complete integration, Gisela also allows extensions and
modifications due to the general computation model and well-defined APIs. We
give a brief overview of the declarative model underlying Gisela and we present
the methodology proposed for building applications together with some real
examples.
