Appendix B. OCL Grammar Rules

This appendix describes the grammar for OCL context declarations and expressions. This section is taken from [OCL03], which is the part of the UML 2.0 OMG standard that defines OCL. A free version of the Octopus tool, which implements this grammar, is available from the Klasse Objecten Web site: www.klasse.nl/ocl.

The grammar description uses the EBNF syntax, in which means a choice, ? means optionality, * means zero or more times, and + means one or more times. In the description, the syntax for lexical tokens is not made explicit. Instead, it is indicated by <String>. This enables developers to use the grammar together with different natural language alphabets.