From 2e03d3c30a3205729ced20294e3eee472b14b118 Mon Sep 17 00:00:00 2001 From: Mark Davis Date: Thu, 5 Oct 2023 17:58:43 +0200 Subject: [PATCH] CLDR-16249 Describe EBNF syntax more clearly (#3322) --- docs/ldml/tr35.md | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/docs/ldml/tr35.md b/docs/ldml/tr35.md index 0946fa589ff..943c86997c0 100644 --- a/docs/ldml/tr35.md +++ b/docs/ldml/tr35.md @@ -246,7 +246,13 @@ External specifications may also reference particular components of Unicode loca > _Field X can contain any Unicode region subtag values as given in Unicode Technical Standard #35: Unicode Locale Data Markup Language (LDML), excluding grouping codes._ +### EBNF +The BNF syntax used in LDML is a variant of the Extended Backus-Naur Form (EBNF) notation used in [W3C XML Notation](https://www.w3.org/TR/REC-xml/#sec-notation). The main differences are: +1. Bounded repetition following Perl regex syntax is allowed, such as alphanum{3,8} +2. Constraints (well-formedness or validity) use separate notes + +In the text, this is sometimes referred to as "EBNF (Perl-based)". ## What is a Locale?