Summary

Scope-objective

This Recommendation defines the comprehensive features of the Specification and Description Language. Together with Recommendations ITU-T Z.100, Z.101, Z.103, Z.104, Z.105 and Z.106 this Recommendation is part of a reference manual for the language. The language defined in this document covers features of the language not included in basic SDL in Recommendation ITU-T Z.101 that provide comprehensive coverage of abstract grammar of the language except some data features covered in Z.104.

Coverage

The Specification and Description Language has concepts for behaviour, data description and (particularly for larger systems) structuring. The basis of behaviour description is extended finite state machines communicating by messages. Data description is based on data types for values and objects. The basis for structuring is hierarchical decomposition and type hierarchies. A distinctive feature of the Specification and Description Language is the graphical representation. This Recommendations covers additional features to Recommendation ITU-T Z.101. The concrete grammar given is the graphical representation. The alternative textual programming representation is given in Recommendation ITU-T Z.106. The concrete grammar in this Recommendation with Recommendations ITU-T Z.101 and Z.104 gives a canonical syntax, which is extended in Z.103 to a syntax that is easier to use. The features of the language defined in Recommendation ITU-T Z.102 make the language more comprehensive.

Applications

The Specification and Description Language is applicable within standard bodies and industry. The main applications areas for which the Specification and Description Language has been designed are stated in Z.100, but the language is generally suitable for describing reactive systems. The range of application is from requirement description to implementation. The features of the language defined in Recommendation ITU-T Z.102 allow more complex models to be defined than is practical with Z.101, but without the features of Recommendation ITU-T Z.103 that make the language more concise and informative. This Recommendation provides a basis for the features defined in Recommendation ITU-T Z.103, which (with Z.104 for data) completes the main language feature set.