BNF

Syntax description language

BNF stands for Backus-Naur Form (or Backus Normal Form), a notation for describing the syntax of programming languages and other formal grammars.

Each rule defines how a symbol can be replaced by a sequence of other symbols: <digit> ::= 0 | 1 | 2 | 3.

BNF and its variants (EBNF, ABNF) remain standard tools for specifying language grammars in computer science documentation.

formalism

context-free

Needing no surroundings

metalanguageVocabulary describing linguistic structure
notationSystem of written symbols
specificationDetailed technical requirement

expressiveness · standardization

structure

production

Making or generating something

ruleGoverning principle or standard
terminalAt the endpoint
symbolRepresentational mark or sign

derivation · expansion · alternation · concatenation · recursion · sequence · rewrite · substitution · definition · optional

parsing

compiler

Source-to-machine-code translator

parserSyntax-interpreting program
tokenizerText segmentation tool
ambiguityOpenness to multiple interpretations

lookahead · backtracking

variants

augmented

Increased in size/value

extendedLengthened in time or space
bisonLarge wild ox

Categories

fansfan, sports fan, superfan, superfans, die-hard fan
RC HobbyRC cars, RC helicopters, RC boats, RTF, hobby shop
British ReferencesOED, Oxford English Dictionary, Oxford Dictionary, Roget's Thesaurus, Who's Who
fandomfandom, fandoms, fan club, fan base, fanbase
model aircraftmodel airplane, model kits, RC helicopter, quadcopter, model aircraft
fanspeakOTP, ship, fic, fanfic, fanfiction

Opposites

meta-level vs. object-level

Programming instructions before compilation

implementation · object code · machine code

abstraction vs. implementation

BNFmachine code

CPU-executable binary instructions

production code

formality of language description

Documentation file convention

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Profile: Used worldwide · Timeless · Abstract · Rated G