Mapping Characters for Classes of the Preparation, Enforcement, and Comparison of Internationalized Strings (PRECIS)
RFC 7790

Approval announcement
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From: The IESG <>
To: "IETF-Announce" <>
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Subject: Document Action: 'Mapping characters for PRECIS classes' to Informational RFC (draft-ietf-precis-mappings-12.txt)

The IESG has approved the following document:
- 'Mapping characters for PRECIS classes'
  (draft-ietf-precis-mappings-12.txt) as Informational RFC

This document is the product of the Preparation and Comparison of
Internationalized Strings Working Group.

The IESG contact persons are Ben Campbell, Barry Leiba and Alissa Cooper.

A URL of this Internet Draft is:

Technical Summary

This document provides guidelines for supplemental and alternative
handling of some Unicode characters in the context of PRECIS (RFC 7564).
The supplemental handling covers mapping of protocol-specific delimiters 
(e.g., "@") and special characters (e.g., mapping of non-ASCII space to 
ASCII space). The alternative handling covers language-specific mapping
of uppercase characters to lowercase characters (e.g., Turkish dotless
i) as an alternative to Unicode Default Case Folding, along with one 
instance of context-specific mapping (Greek final sigma).

Review and Consensus

Internationalization is full of messy complexity. The topic of case
mapping, although it might seem straightforward to English speakers, can
be far from clear-cut.  Because of the complexities involved, the sense
of the PRECIS WG was that it could not provide normative recommendations
for case mapping beyond those defined in the Unicode Default Case
Folding algorithm. Nevertheless, the working group saw value in
providing informational guidance regarding language-, locale-, and
context-dependent mappings. This is similar to the relationship between
the core Internationalized Domain Names in Applications (IDNA) protocol
and the informational guidance provided in RFC 5895. 

In contrast to the topic of case mapping, the guidelines regarding
delimiter mapping and special mapping were uncontroversial and elicited
no significant concern among working group participants.

The document shepherd is Peter Saint-Andre.
The responsible Area Director is Barry Leiba.