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3.2. Meta Meta Model Comparison
Port
(in)
Object1
Port
(out)
Role
Relationship
Role
Port
(in)
Object2
Port
(out)
Figure 3.20.: GOPRR concrete binding syntax with ports
certain roles and a certain relationship. In Figure 3.20, roles and relationship are the same,
but the objects are connected only indirectly by their ports (out and in). Therefore, it can
be modelled that only certain ports can be connected under certain roles and relationship.
For example, a connection out→out or in→in could be avoided in Figure 3.20. The concrete
syntax of the GOPRR meta meta model consists of further elements for describing sub-graph
connections by decompositions and explosions, but which are not explicitly introduced here.
Figure 3.21 shows the instantiation of GOPRR in DSM architectures.
GOPRR
instantiates
Graphical Meta Model
instantiates
Graphical Model
instantiates
Code
Figure 3.21.: GOPRR DSM instances
3.2. Meta Meta Model Comparison
Generally, DSLs can be divided in two categories:
• textual
• graphical
A textual model is defined by text statements while a graphical model is defined by graphics.
Of course, combinations of both are also possible. The difference between those two types
cannot be explained completely in general because this is also a matter of the concrete problem
domain. A general discussion can be found in [46, p. 50ff].
A goal of this work – modelling an ATP system – includes the development of a meta model
for the corresponding specification, the ETCS SRS. These documents are mostly written in
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