The SML language for structured modeling: Levels 1 and 2

This is the first of two articles on the principal features of SML, a language for expressing structured models. SML is presented in terms of four ‘levels’ of increasing expressive power; this article covers the first two levels, while he sequel covers levels 3 and 4. The lower levels, at least, are easy to learn. Both articles rely entirely on examples and give special attention to the characteristics of SML that, collectively, make it unique. The intended audience includes evaluators of other modeling languages, designers of modeling languages and systems, and those who follow the development of structured modeling.