Constraint Based Transformation Theory Document Type Transfer Report

The migration of a legacy system is one of the most challenging tasks in the area of software evolution. There are existing several different approaches to migrate a legacy system with different advantages and disadvantages. One solution is to translate the software into an intermediate language which spans from the low abstraction level to the very high abstraction level. Once the software has been translated to intermediate language the abstraction level can be changed via mathematical proven transformation rules. Afterwards, a translator can easily translate the intermediate language into the target language. A very powerful intermediate language was invented by Martin Ward at the University of Oxford. This Language is called "Wide Spectrum Language" or "WSL". He also defines a set of mathematical proven code transformations and an environment to apply these transformations to WSL. This environment is called "FermaT Transformation Engine". In this report we will present initial work on a framework for a constraint based transformation system which gives the maintainer the possibility to apply constraint based code transformations with the FermaT Transformation Engine. It will review some of the achievements and outline the motivation and objectives for the proposed development framework. Furthermore, it reviews literature from the code transformation, constraint programming and expression language domain. Document Type Transfer Report Author Stefan Natelberg Date 29th November 2007 Version 1.0 Inspected Prof. Hussein Zedan