The higher abstraction in
models using domain experts??™ concepts also means that the generated output can be
easily changed to some other implementation language.
Generated Output The ?¬?fth and last category of concept sources is the
generation target of the language: the concepts and structures we see in the code to be
generated are mapped directly into the modeling language. One of the most typical
cases here is de?¬?ning a metamodel based on the schema of the XML to be generated:
Each tag type refers to a concept in a modeling language. While these languages are
easy to build, their ability to increase productivity and quality is questionable. There is
a danger of creating languages like class diagrams: presenting a class as a rectangle
that maps one to one to a line in a ?¬?le. This kind of language may still be valuable when
the generated output is already in a domain-speci?¬?c language, like a particular XML
format. The XML schema will provide you with a wealth of information for
identifying the modeling concepts and constraints. To follow the XML metaphor,
designs can be considered valid and well-formed right at the modeling stage.
Graphical models can also help overcome many of the limitations of XML.
236 DSM LANGUAGE DEFINITION
An example of this kind of DSM language is the Call Processing Language (CPL),
which is used to describe and control Internet telephony services (see Fig.
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