  This paper contains a brief discussion of an object evaluator which is based
on principles of evaluations in a category. The main tool system referred as
the Application Development Environment (ADE) is used to build database
applications involving the graphical user interface (GUI). The separation of a
database access and the user interface is reached by distinguishing the
potential and actual objects. The variety of applications may be generated that
communicate with different and distinct desktop databases. The commutative
diagrams' technique allows to involve retrieval and call of the delayed
procedures.
