2. ABSTRACT SYNTAX AND SEMANTICS OF DCHARTS

The definition of DCharts 1.0, the current version of DCharts, contains two parts: the syntax answers the question ``what is the structure of a DCharts model?'' while the semantics answers ``what is the meaning of a DCharts model?'' The following criteria influence the syntax and the semantics:

• The syntax must be rich enough to allow the specification of a complete semantics. I.e., if a semantic element cannot be specified according to the syntax, there is no way to design a model that uses it, and hence the element becomes useless.

• Every syntactically correct model must have a unique meaning according to the semantics.

• The definition of syntax must facilitate both computer processing and human understanding.

• The semantics should be as platform/implementation-independent as possible. This allows the formalism to be implemented by different tools and to be used in different systems.

The following sections describe the basic syntax and semantics of DCharts 1.0.