ISO IEC 14977-1996 PDF

Full title and description

ISO/IEC 14977:1996 — Information technology — Syntactic metalanguage — Extended Backus‑Naur Form (EBNF). This international standard specifies a metalanguage for formally describing the syntax of languages, data formats and protocols using the Extended Backus‑Naur Form notation, including lexical conventions, production rules and the concrete representation of terminals and meta‑identifiers.

Abstract

ISO/IEC 14977 defines the syntax and notation of EBNF as a compact, human‑readable metalanguage for specifying context‑free grammars. The standard documents the symbols and constructs used (concatenation, alternatives, optional items, repetition, exception, grouping, special sequences, comments, terminals and non‑terminals) and establishes lexical rules and conventions to ensure consistent grammar descriptions across specifications and implementations.

General information

• Status: Published (international standard).
• Publication date: 1996.
• Publisher: International Organization for Standardization (ISO) and International Electrotechnical Commission (IEC), published under ISO/IEC JTC 1.
• ICS / categories: Information technology; syntactic metalanguage and language specification (ICS 35.040).
• Edition / version: 1996 edition (original international standard).
• Number of pages: approximately 30 pages.

Scope

The standard specifies a single, well‑defined concrete syntax for Extended Backus‑Naur Form that can be used to describe the syntactic structure of programming languages, protocol formats, file formats and other formal languages. It covers the notation for productions, meta‑identifiers and terminals, operators for repetition and option, grouping and alternatives, special sequences, lexical items and the recommended presentation and interpretation rules for grammar authors and implementers.

Key topics and requirements

• Definition of EBNF lexical elements: meta‑identifiers, terminals and special sequences.
• Production rules: formal syntax for defining grammar productions and right‑hand side constructs.
• Operators and constructs: concatenation, alternatives (choice), optional items, repetition (zero or more, one or more), exceptions and grouping.
• Representation rules: notation for quoting, escaping, comments and presentation conventions to avoid ambiguity.
• Guidance on equivalence to classical BNF and interoperability considerations for grammar processors and parser generators.
• Examples demonstrating common grammar patterns and recommended usage to produce clear, maintainable specifications.

Typical use and users

Language designers, compiler and interpreter developers, standards authors, protocol designers, documentation writers and tool implementers (parser generators, syntax checkers) use ISO/IEC 14977 to produce unambiguous, portable grammar descriptions. It is commonly referenced in programming language standards, technical specifications and academic writing where a formal, human‑readable grammar notation is required.

Related standards

Standards and specifications concerned with grammar notation and language specification are related, including other metalanguages (for example ABNF used in Internet specifications), and language‑specific standards that adopt or reference EBNF. Implementers should also consider parser generator tool documentation and any language‑specific extensions or profiles used in conjunction with ISO/IEC 14977.

Keywords

EBNF, Extended Backus‑Naur Form, syntactic metalanguage, grammar, production rules, terminals, non‑terminals, parser, syntax specification, language definition.

FAQ

Q: What is this standard?

A: ISO/IEC 14977:1996 is the international standard that defines the concrete syntax and notation of Extended Backus‑Naur Form (EBNF) for formally describing the syntax of languages and data formats.

Q: What does it cover?

A: It covers the formal notation used in EBNF: meta‑identifiers, terminals and special sequences; production rules; operators for choice, repetition, optional items and exceptions; grouping and lexical conventions, plus guidance and examples for producing clear grammar specifications.

Q: Who typically uses it?

A: Language and protocol designers, standards authors, compiler and interpreter developers, documentation writers and tool vendors producing or consuming formal grammar descriptions.

Q: Is it current or superseded?

A: The document is the 1996 edition of ISO/IEC 14977 and remains the authoritative international specification for EBNF notation. Users who require the absolute current status or any amendments should consult ISO/IEC or their national standards body for the latest cataloguing information or possible updates.

Q: Is it part of a series?

A: ISO/IEC 14977 is published as a single standalone standard specifying EBNF; it is not part of a numbered multi‑part series, though it is often used alongside other language or information‑technology standards.

Q: What are the key keywords?

A: EBNF, Extended Backus‑Naur Form, grammar, syntactic metalanguage, production, terminal, non‑terminal, syntax, parser.