Re: case insensitive match in unicode - Mailing list pgsql-general

On Mon, Mar 27, 2006 at 12:45:05PM +0200, SunWuKung wrote:
> This sounds like a very interesting concept.
> It wouldn't be 'case insensitive' just insensitive.
>
> The way I imagine it now is a special case of the ~ function.
> I create matchgroups in a table and check each character if it is in the
> group. If it is I will replace the character with the group in [éÉE],
> [oóOÓ??] and do a regexp with that.

No need to reinvent the wheel. ICU provides a range of services to deal
with this. For example the following filter in ICU:

 NFD; [:Nonspacing Mark:] Remove; NFC.

Will remove all accents from characters. And it works for all Unicode
characters. With a bit more thinking you can work with case variations
also.

There is also a locale-independant case-mapping module there plus
various locale specific ones also.

http://icu.sourceforge.net/userguide/Transform.html
http://icu.sourceforge.net/userguide/caseMappings.html
http://icu.sourceforge.net/userguide/normalization.html

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> tool for doing 5% of the work and then sitting around waiting for someone
> else to do the other 95% so you can sue them.