These components are then characterized with an additional property for
specifying the platform, i.e., ???applet and awt??? or ???midlet.??? Depending on the target,
the generator then reads the platform properties given in models and includes the right
242 DSM LANGUAGE DEFINITION
components along with the code generated from the models. The same principle is
also normally followed in cases where there is a need for different generators for
different purposes, like one for early prototyping, one for producing code with model
debugging information, and one for generating production code.
Supporting Variation in Languages Most domain engineering approaches
(e.g., Kyo et al., 1990; Arango, 1994; White, 1996;Weiss and Lai, 1999) emphasize
language as an important mechanism to handle variation. This means that variation
is represented right in the metamodel. In the simplest case, a variation point is
de?¬?ned as a property of a modeling concept. The possible parameters of variation
can be further de?¬?ned as prede?¬?ned values from which a modeler chooses the right
one. In the watch case, for instance, each display element can be speci?¬?ed by the
icons it may use. These are de?¬?ned in the metamodel as a property type having as
prede?¬?ned values the icons that can be used. A modeler then just picks one or more
of them depending on his need.
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