Introduction

MSL (Model Specification Language) is a language used to represent models. Three formats of MSL are defined: MSL-USER, MSL-EXEC and MSL-XML.

MSL-USER is the high-level language used to specify the models in the model library. Using this language specification it is possible to create new models, or modify existing models. Since MSL-USER is a modeling language rather than a programming language, it allows for describing the structure of models, rather than for specifying instructions on how to execute them. In this respect, MSL-USER can be termed a declarative language.

The MSL-USER language provides for the following:

A hierarchy of classes, built from lists of attribute/value pairs
Inheritance features
A set of "standard" classes as a backbone for the language
Means for implementing new classes that are of importance for the modeling exercise

Using the WESTŽ model compiler, a model represented in MSL-USER can be transformed into MSL-EXEC format, which is based on C.

The MSL-USER format can also be transformed into the MSL-XML format. The latter format is used to represent basic model information features in a way that is easily machine-readable, and is of minor significance to most WESTŽ users.

In the remainder of this document only the MSL-USER format is described. All references to MSL refer therefore to the MSL-USER format.