Backus-Naur form

English

Etymology

From the names of computer science pioneers John Backus and Peter Naur. The notation was developed by Backus in 1959 (as Backus normal form) to describe computer languages, specifically ALGOL 58, and expanded and used by Naur in the ALGOL 60 report (the result of a January 1960 meeting). The name change to Backus-Naur form was at the suggestion of Donald Knuth.[1]

Pronunciation

(Received Pronunciation) IPA^(key): /bækəs naʊə fɔːm/
(General American) IPA^(key): /bækəs naʊɚ fɔɹm/

Noun

Backus-Naur form (countable and uncountable, plural Backus-Naur forms)

(computing) A formal notation for context-free grammars. [From 1964.]
- 1991, Bernd Teufel, Organization of Programming Languages, Springer, page 26,
  While context-free grammars (which, by the way, directly correspond to Backus-Naur forms) define the syntax of declarations, statements, and expressions, etc. (i.e. the structure of a program), the regular grammars define the syntax of identifiers, numbers, strings, etc. (i.e., the basic symbols of the language).
- 2004, Jason H. Moore, Lance W. Hahn, Systems Biology Modeling in Human Genetics Using Petri Nets and Grammatical Evolution, Kalyanmoy Deb, et. al. (editors), Genetic and Evolutionary Computation, GECCO 2004, Proceedings, Part 1, Springer, LNCS 3102, page 396,
  Here, a Backus-Naur Form (BNF) grammar is specified that allows a computer program or model to be constructed by a simple genetic algorithm operating on an array of bits.
- 2011, Airi Salminen, Frank Tompa, Communicating with XML, Springer, page 215,
  The most common syntactic metalanguage adopted in the computing world is Extended Backus-Naur Form (EBNF). There are many slightly different variants of EBNF, but all of them are based on Backus-Naur Form (BNF), developed in the 1960s for describing the syntax of the Fortran and Algol 60 programming languages.

Usage notes

The plural may be used when referring to instances of the notation's use (as a form of description of specific grammars) or to specific versions (especially extensions) of the notation.

In computer science, Backus-Naur form is now superseded by extended Backus-Naur form, a family of metasyntax notations encompassing BNF. An EBNF standard was adopted by the International Organization for Standardization (ISO) in 1996 as ISO/IEC 14977. Also in 1996, the World Wide Web Consortium (W3C) used an EBNF to specify XML.

Synonyms

(formal notation): Backus normal form (obsolete), BNF (abbreviation)

Derived terms

(formal notation): augmented Backus-Naur form (ABNF), extended Backus-Naur form (EBNF)

Translations

a formal notation for context-free grammars

Esperanto: formo de Backus-Naur
Icelandic: Backus-Naur-ritháttur m, Backus-Naur ritháttur m

References

1964, Donald E. Knuth, Backus normal Form vs Backus Naur Form, Communications of the ACM 7:12, pages 735–6.