HyperMSC - a Graphical Representation of TTCN

The development of an MSC based graphical representation of TTCN is part of the ETSI project STF 156 on 'Specification of a Message Sequence Chart/UML format, including validation for TTCN-3'. The most important language constructs of TTCN can be translated into corresponding MSC constructs in a straightforward manner. However, it turns out that without certain extensions and modifications, the ITU standard language MSC is not capable to produce a sufficiently transparent and readable graphical representation of TTCN. In order to arrive at a really convincing solution, HMSCs are re-interpreted in a way, which has an analogy in hypertext -like specifications. MSC references may be shown also in an expanded manner and non-expanded MSC references may contain hypertext -like descriptions instead of pure reference names. As a result, there does not exist a strict borderline between HMSCs and BMSCs any longer. Such a generalisation of MSC is really efficient only together with a corresponding tool support, which allows the smooth transition between different levels of detailed description similarly to hypertext. Therefore, the name 'HyperMSC' is proposed for such extended HMSCs. The paper demonstrates how HyperMSCs arise from standard MSC descriptions in an evolutionary process of stepwise improvement and simplification.