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Also, a couple of earlier versions of the same tutorial: How To Start.. | Obsolete Getting Started With MPS
ToDo: nice to have the sample project attached
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Extending the BaseLanguage screencast by Konstantin Solomatov
This screencast shows how BaseLanguage can be extended with new kind of statement. Among other things it also gives an example of adding of a custom typesystem and control-flow analysis to your language.
ToDo: nice to have the sample project attached