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4The GOPPRR Meta Meta Model –
An Extension of GOPRR
On account of the idea of using a DSL to directly provide additional artefacts for the certification
procedure for dependable software, the definition of the abstract syntax [46, pp. 68-69] –
including the definition formalism – is crucial. In relation to this work, this primary means
the selection of the meta meta model and the developed meta model. Although the selected
GOPRR meta meta model provides a good documentation (Chapter 3), the formalisms for
defining the syntax of meta models have to be evaluated.
The definition of the concrete syntax [46, p. 70] and the static semantics [46, pp. 69-70]
of the underlying meta model is a very important task in the development of safety-critical
software under the model-driven architecture (MDA) [44] paradigm. The concrete syntax
defines how models can be instantiated from a meta model. Falsely or too “loose” defined
concrete syntaxes may lead to models instantiated from those that are in conflict with the
required safety properties for the modelled system or software. Those errors in the model could
have an impact on all lower instances of a DSL down to the executable binary code.
GOPRR is a graphical meta meta model, which makes the decision for a graphical syntax
description formalism obvious. The main advantage is that the syntax description of a meta
model can be also defined as meta model of GOPRR. This results in the situation that a
concrete syntax description is also a model of the same meta meta model. The complete and
detailed description of the original GOPRR syntax description formalisms can be found in [45,
app. A] and [56].
Unfortunately, the GOPRR syntax description meta model does not include ports (Subsection
3.1.5), but which are also elements of the meta meta model. Concrete explanations for this
could not be found in the corresponding documentation, but a possible reason might be that
ports were added later to the meta meta model. This might also be reflected in the acronym
GOPRR (Graph, Objects, Properties, Roles and Relationships), which does not include a letter
for ports. However, ports provide in some cases great advantages for meta models and are
also heavily used in the case study presented in Part III for an interfacing concept. Without
ports, this could only have been realised with a much more complex concrete syntax or rather
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