Manfred Widera

Flow graphs for testing sequential erlang programs

Testing of software components during development is a heavily used approach to detect programming errors and to evaluate the quality of software. Systematic approaches to software testing get a more and more increasing impact on software development processes. For imperative programs there are several approaches to measure the appropriateness of a set of test cases for a program part under testing. Some of them are source code directed and are given as coverage criteria on flow graphs.This paper gives a definition of flow graphs for Erlang programs and describes a tool for generating such flow graphs. It provides a first step towards the transfer of advanced source code directed testing methods to functional programming.

An extendable system for the specification and generation of interactive self-tests

The system Asterix was developed in the context of distance teaching in order to support the direct feedback of a students learning progress. Asterix contains different interactive tasks from the area of the formal foundations of computer science. Students can access the system by means of an internet interface. The implementation of the interactive presentation and correction of the tasks is generated automatically from high-level XML specifications. In this work we give an overview of the essential features of the system and the supported task types and show how Asterix is used in the context of distance teaching at the FernUniversitat in Hagen.

Combining Strict and Soft Typing in Functional Programming

We discuss the properties of strictly typed languages on the one hand and soft typing of the other and identify disadvantages of these approaches to type checking in the context of powerful type languages. To overcome the problems we develop an approach that combines ideas of strict and soft typing. This approach is based on the concept of complete typing that is guaranteed to accept every well-typed program. The main component of a complete type checker is defined.