László Lövei

Refactoring module structure

This paper focuses on restructuring software written in Erlang. In large software projects, it is a common problem that internal structural complexity can grow to an extent where maintenance becomes impossible. This situation can be avoided by careful design, building loosely coupled components with strictly defined interfaces. However, when these design decisions are not made in the right time, it becomes necessary to split an already working software into such components, without breaking its functionality. There is strong industrial demand for such transformations in refactoring legacy code. A refactoring tool is very useful in the execution of such a restructuring. This paper shows that the semantical analysis required for refactoring is also useful for making suggestions on clustering. Existing analysis results are used to cover the whole process of module restructuring, starting with planning the new structure, and finishing by making the necessary source code transformations.

Impact analysis of erlang programs using behaviour dependency graphs

During the lifetime of a software product certain changes could be performed on its source code. After those changes a regression test should be performed, which is the most expensive part of the software development cycle. This paper focuses on programs written in a dynamic functional programming language Erlang, and discusses a mechanism that could select those test cases, which are affected by a change, i.e. altering the program on some point may have impact on the result/behaviour of those test cases. In the result of that analysis it is possible to reduce the number of necessary test cases, and after modifying the source code, just a subset of the test cases should be retested. The discussed approach introduces a behaviour dependency graph for Erlang programs to represent the dependencies in the source code. The impact of a change can be calculated by traversing the graph.

Introducing records by refactoring

This paper focuses on introducing a new transformation to our existing model for refactoring Erlang programs. The goal of the transformation is to introduce a new abstraction level in data representation by substituting a group ofrelated data with a record. Using records enhances the legibility of the source code, makes further development easier, and makes programming less error-prone by providing better possibilities for both compilation time and runtime checks. There is a strong industrial demand for such a transformation in refactoring legacy code. Erlang is a dynamically typed language, and many of its semantical rules are also dynamic. Therefore the main challenge in this research is to ensure the safety of statically performed refactoring steps.

Automated module interface upgrade

During the lifetime of a software product the interface of some used library modules might change in such a way that the new interface is no longer compatible with the old one. This paper proposes a generic interface migration schema to automatically transform the software in the case of such an incompatible change. The solution is based on refactoring techniques and data flow analysis, and makes use of a formal description of the differences between the old and the new interfaces. The approach is illustrated with a real-life example.

Software engineering education in cooperation with industrial partners

This paper presents our experiences on teaching software engineering in teams which are organized around different R+D projects. These long-running, innovative projects are carried out in cooperation with industrial partners, and are supported by student exchange. While MSc and PhD students work together with faculty staff members on the projects in an industrial-like environment, the students develop skills that would be otherwise very hard for them to obtain. The methodological contributions of the paper are illustrated by, and substantiated with, the description of a concrete software engineering project.