Don't Use ISO/IEC 14977:1996 Extended Backus-Naur Form (EBNF) (2023)

Don’t Use ISO/IEC 14977:1996 Extended Backus-Naur Form (EBNF) David A. Wheeler If you need to define a language (such as a programming language or complex data structure) it’s often helpful to use some kind of Extended Backus-Naur form (EBNF). Often people do a Google search, find out that there’s an ISO/IEC standard (ISO/IEC 14977:1996), and then just use it... without realizing that this very old ISO/IEC standard has a lot of problems and should not be used. In this essay I will briefly explain the problems of the ISO/IEC 14977:1996 specification, and why I think you should avoid using it. I will first discuss the many technical failings of the specification itself, then follow that with why just mindlessly obeying ISO is inappropriate (since some people may do that). When I discuss its failings I will also compare the 14977 specification to a common alternative, the EBNF notation from the W3C Extensible Markup Language (XML) 1.0 (Fifth Edition). I'll also briefly mention IETF's R ... Read full article.