Kjetil Torgrim Homme wrote:
Subject: discuss: draft-ietf-sieve-variables
Date: Wed, 26 Oct 2005 14:41:34 -0400 (EDT)
From: Sam Hartman <hartmans-ietf(_at_)mit(_dot_)edu>
The :lower and :upper and other case-folding modifiers to the set
action do not seem to have a well defined case mapping for
internationalization. It is true that the ACAP i;ascii-casemap does
define a case folding table for part of Unicode. However I don't
understand how that's generally true or how consulting a comparator
will tell me which locale to use.
Please provide information on how the four ACAP comparator operations
can be consulted to determine how to map case. Alternatively, provide
another solution or extend the definition of ACAP comparator
sufficiently to meet your needs.
this is indeed the weakest part of the variables spec, I admit the use
of a comparator with SET is little more than handwaving to appease the
i18n concious :-). the text is even careful to avoid implying that the
comparator _has_ such a mechanism:
The comparator specified SHOULD be consulted to establish which
locale to use.
"consulted" isn't very normative. it was a trick, and Sam caught me. I
had hoped this would slide, and later we could fix up comparators
"properly" by adding two new operations (upper case and lower case).
however, such operations can hardly be called comparisons, and they're
unary, not binary, so it's probably not such a hot idea.
Indeed. Let's not call it "comparator".
another option is to leave out the whole comparator thing, and just say
(as it does already) that US-ASCII MUST be supported. after all, all
strings in Sieve are UTF-8 encoded characters from the ISO 10646
repertoire anyway, so by not saying anything about it, we make it a
quality of implementation issue. which it would be, _anyway_.
I think it is the quickest way to address the issue. Besides, one can
document/implement something like ":upper_cyrillic" modifier.
(at the same time, we could get rid of the Unicode reference.)
thoughts?