Informatica

In the paper, we describe our approach and experience with teaching fundamentals of functional programming by program schemata construction and explanation. Program schemata for processing of lists are presented. Our approach reflects our ultimate goal – to support the learning process. As the main result, we report on experiments that allow to judge quite favourably the approach to teaching functional (Lisp) programming when the student learns a set of program schemata and how to apply them.

In this paper we examine data dependence in a nested loop programs which are obtained by inserting one loop program into another. This is viewed as the composition of structural modules (S-modules) in the structural blanks (SB) approach. SB is a method for expressing computations based on recurrence relations. It is built on top of traditional programming languages like Fortran or Pascal. SB aims at supporting the transformational development and reuse of program modules that have complex data dependence patterns and provides an architectural framework for software packages.

An extention of the QBE language in the form of graph queries is proposed for databases having complex schemata. These graph queries provide user interface for the ER model, like QBE queries provide user interface for the relational model. The implementation and usage of graph queries of ER-based “MicroPoisk” DBMS are presented.

Statelog is a Datalog extension integrating the declarative semantics of deductive rules with the possibility to define updates in the style of active and production rules. The language is surprisingly simple, yet captures many essential features of active rules. After reviewing the basics of active rules, production rules, and deductive rules, we elaborate on the problem of handling rule termination in the context of Statelog: It is undecidable whether a Statelog program terminates for all databases, and PSPACE-complete for a given database. The latter can be accomplished within the logical language: for every Statelog program P, there is a terminating program P^↓ which decides for any given database 𝒟, whether P ∪ 𝒟 terminates.

Attributed automaton (AA) is a formalism for conceptual knowledge specification using regular syntax with attributes representing contextual relations as well as semantic properties of concepts. AA can be treated as a generalization of a finite automaton with attributes and computational relations attached to states and transitions respectively. In this paper we develop a new specification method for AA based on functional combinators. It allows modular specification of AA, enjoys good algebraic properties and is extendable for different kind of attributed automata.

This paper presents the declarative extension of the deductive database system LOLA to the object-oriented deductive database system O!-LOLA. The model used for O!-LOLA is “objects as theories”, extended by state evolution. O!-LOLA combines logic programming and OO programming in two different ways: First, methods are implemented as logic programs. These methods can be inherited, encapsulated and overloaded. Second, logic programs can be defined over classes, meta-classes, instances, attributes and values. Dynamic updates of attributes of objects and dynamic instantiations of classes are supported.