ECMAScript collation question

Nebojša Ćirić cira at
Fri Aug 31 08:24:24 PDT 2012

This is what Markus had to say (he implemented most of the collation for


Step 1 of the algorithm:
which has a note:

   - Conformant implementations may skip this step *in certain
   circumstances: *see *Section 6.5, Avoiding
   * for more information.

See also
-> attribute "normalization", see the description there
(this whole table 14 will soon move to the LDML spec, leaving only a link
in this place)"

So the question is:

1. Do we change i18n API default for normalization to always be true, with
some performance penalty?
2. Update ES 262 spec with info Markus passed (if possible)?

2012/8/30 Mark Davis ☕ <mark at>

> ICU *is* always able to compare them as being equal, just by setting the
> parameter.
> Even if the parameter isn't set, it uses an FCD sort (see
> and canonical closure, which handles most
> cases of canonical equivalence. The default is turned on for languages
> where the normal+auxiliary exemplar sets contains characters that would
> show a difference even with an FCD+closure sort, and can be turned on
> always if desired (at some cost in performance; 30% sounds high though).
> Mark <>
> *
> *
> *— Il meglio è l’inimico del bene —*
> **
> On Thu, Aug 30, 2012 at 6:30 PM, Norbert Lindenberg <
> ecmascript at> wrote:
>> In particular, a conformant implementation must be able to compare any
>> two canonical-equivalent strings as being equal, for all Unicode characters
>> supported by that implementation."

Nebojša Ćirić
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