Preface:

Standards development within the Information Technology sector is harmonized with international standards development. Through the CSA Technical Committee on Information Technology (TCIT), Canadians serve as the Canadian Advisory Committee (CAC) on ISO/IEC Joint Technical Committee 1 on Information Technology (ISO/IEC JTC1) for the Standards Council of Canada (SCC), the ISO member body for Canada and sponsor of the Canadian National Committee of the IEC. Also, as a member of the International Telecommunication Union (ITU), Canada participates in the International Telegraph and Telephone Consultative Committee (ITU-T).

Scope:

This International Standard defines a notation, Extended BNF, for specifying the syntax of a linear sequence of symbols. It defines both the logical structure of the notation and its graphical representation.

Extended BNF has applications in the definition of programming and other languages, as well as in other formal definitions, for example the commands to an operating system, or the precise format of data and results.

Examples of Extended BNF are given in clause 8.

NOTE — Like many other notations, Extended BNF can still be misused; thus it does not prevent someone from trying to define an unparsable or ambiguous language.