Backus-Naur form

This ontology contains terms for defining a context-free grammar. The basic property is mustBeOneSequence which is equivalent to the expression of a production in the original simple BNF. Rules can be used to convert into and out of shorthand forms such as optional, repeating and token-separated list forms. Terminals are described either as a string, which is represented by itself, or are defined by a regular expression using cfg:matches.