Industrial automation systems and integration -- Product data representation and exchange -- Part 11: Description methods: The EXPRESS language reference manual
This standard has been revised by ISO 10303-11:2004
Defines a language called EXPRESS which consists of language elements which allow an unambiguous data definition and specification of constraints on the data defined and by which aspects of product data can be specified. Deals with data types and constraints on instances of the data types. Also defines a graphical representation (EXPRESS-G) for a subset of the constructs in the EXPRESS language. EXPRESS is not a programming language.