[2] R-BNF は、EBNF と正規表現を組み合わせた構文記述言語です。
[1] Developer's Guide (v2) - Google Safe Browsing API - Google Code ( 版) http://code.google.com/intl/ja/apis/safebrowsing/developers_guide_v2.html#ProtocolSpecificationRBNF
This document uses a R-BNF notation, which is a mix of Extended BNF and PCRE-style regular expressions:
Rules are in the form: name = definition. Rule names referenced as-is in the definition. Angle brackets may be used to help facilitate discerning the use of rule names.
Literals are surrounded by quotation marks: "literal".
Sequences: (rule1 rule2) or simply rule1 rule2.
Alternatives groups: (rule1 | rule2).
Optional groups: [rule[]].
Repetition: rule* means 0 or more of this rule or this group.
Repetition: rule+ means 1 or more of this rule or this group.