Constrained ABNF

Document Type Expired Internet-Draft (individual)
Authors Sean Leonard  , Paul Kyzivat 
Last updated 2017-09-14 (latest revision 2017-03-13)
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This document extends the base definition of ABNF (Augmented Backus- Naur Form) to express a rule that is constrained by another rule. If a rule B is constrained by rule A, then every production generated by rule B must also be generated by rule A. By creating subordinate production forms, ABNF-using specifications can formally denote the relationship between a general rule and specific subsets of that rule, while preserving ABNF's context-free nature.


Sean Leonard (
Paul Kyzivat (

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