While usually most of the model data for accessing and navigating models are the
same as the design information, additional model data also can be used. These can
include:
80 ARCHITECTURE OF DSM
. spatial location of model elements, such as size, or location relative to other
elements;
. model administration data, such as creation time, version, or author;
. model annotations that guide the generator but are not needed for ?¬?nding a
solution in the problem domain. These can include selection of target environment,
compiler, and output directory.
If there are multiple models based on different languages, navigation can still be
based on the same principles as accessing just one model. If the languages use
integrated metamodels, a generator can then treat separate models as integrated. If
models are treated separately from each other, the generator integrates the models
during generation, for example, by using string matching or annotations in the model
that show links between models.
Extracting Model Data While navigating in the models, the generator extracts
design data and combines it with a possible domain framework. Again the code
generator can only retrieve information from models that was provided for in
the metamodel. In the simplest case, each modeling element produces certain ?¬?xed
code that includes the values entered by the modeler.
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