Editing Augmented Backus–Naur form (section)

{{Short description|Metalanguage based on Backus–Naur Form (BNF)}}
In [[computer science]], '''augmented Backus–Naur form''' ('''ABNF''') is a [[metalanguage]] based on [[Backus–Naur form]] (BNF) but consisting of its own syntax and derivation rules. The motive principle for ABNF is to describe a [[formal system]] of a language to be used as a bidirectional [[communications protocol]]. It is defined by [https://tools.ietf.org/html/std68 ''Internet Standard 68''] ("STD 68", type case sic), which {{as of|2010|12|lc=on}} was {{IETF RFC|5234}}, and it often serves as the definition language for [[IETF]] communication protocols.<ref name="Internet Standards">{{cite web
|url= http://www.rfc-editor.org/rfcxx00.html
|title= Official Internet Protocol Standards
|access-date= 2010-02-21
|date= 2010-02-21
|publisher= RFC Editor
| archive-url= https://web.archive.org/web/20100209035909/http://www.rfc-editor.org/rfcxx00.html| archive-date= 9 February 2010 | url-status= live}}
</ref><ref name="STD 68">
{{cite web
|url= http://ftp.rfc-editor.org/in-notes/std/std68.txt
|title= Augmented BNF for Syntax Specifications: ABNF
|access-date= 2010-02-21
|last= Crocker
|first= D.
|author2= Overell, P.
|date=January 2008
|format= plain text
|publisher= RFC Editor
|pages= 16
}}
</ref>

{{IETF RFC|5234}} supersedes {{IETF RFC|4234|2234|733|leadout=and}}.<ref name="RFC Index">
{{cite web
|url= http://www.rfc-editor.org/rfc-index2.html
|title= RFC Index
|access-date= 2010-02-21
|date= 2010-02-19
|publisher= RFC Editor
| archive-url= https://web.archive.org/web/20100209041834/http://www.rfc-editor.org/rfc-index2.html| archive-date= 9 February 2010 | url-status= live}}
</ref> {{IETF RFC|7405}} updates it, adding a syntax for specifying case-sensitive string literals.