[idn] TR21

[mark.davis@us.ibm.com]

I wouldn't suggest ignoring TR21. TR21 does more than just lowercasing, so
that it catches problem cases like sigma, sharp s, and dotless i. For
example, if you want <BETA><ALPHA><SIGMA> to match against
<beta><alpha><final-sigma> -- which it certainly should,
and <SIGMA><ALPHA><BETA> to match against <sigma><alpha><beta> -- which it
certainly should,
and you are using case folding (rather than an algorithm), then you have
not choice but to map all three sigmas to a single value.

Mark


James Seng <jseng@pobox.org.sg>@ops.ietf.org on 2000/02/15 06:27:47 PM

Sent by:  owner-idn@ops.ietf.org


To:   Mark Davis/Cupertino/IBM@IBMUS
cc:   Karlsson Kent - keka <keka@im.se>, idn@ops.ietf.org
Subject:  Re: [idn] RE: Normalisation and ASCII fallbacks



Hi Mark,

I am refering to

Kent wrote:
>I suggest ignoring UTR 21.  Just downcase according to the 'default'
>(non-normative) in the main property table for Unicode 3.0.

I am wondering if there is any UTR for this which is unique to 3.0.

-James Seng

mark.davis@us.ibm.com wrote:
>
> Go to www.unicode.org.
> The general data is under "Character Database".
> The case folding information is in a link from UTR#21, under "Technical
> Reports"
>
> [I have not been able to read the slew of messages on this distribution
> list, but happened to see this one. Kent and I have been having a private
> conversation about case-folding vs. lowercasing.]
>
> Mark
> ___
> Mark Davis, IBM Center for Java Technology, Cupertino
> (408) 777-5850 [fax: 5891], mark.davis@us.ibm.com, president@unicode.org
> http://maps.yahoo.com/py/maps.py?Pyt=Tmap&addr=10275+N.+De+Anza&csz=95014
>
> James Seng <jseng@pobox.org.sg>@ops.ietf.org on 2000/02/15 05:07:03 PM
>
> Sent by:  owner-idn@ops.ietf.org
>
> To:   Karlsson Kent - keka <keka@im.se>
> cc:   idn@ops.ietf.org
> Subject:  Re: [idn] RE: Normalisation and ASCII fallbacks
>
> > > To do case folding to lower case, just use the main property table
> > > for Unicode 3.0. This has one to one mapping only which is
> > > very nice as it simplifies data handling.
>
> I am still waiting for my Unicode 3.0 book to arrive but in the meantime,
I
> think it would be useful if anyone can post a pointer to Unicode 3.0 and
> its
> related property such as case folding.
>
> -James Seng