From: James Edward Gray II <james@...>
Date: 2006-10-25T02:19:54+09:00
Subject: Re: downcase part of a string

On Oct 22, 2006, at 8:16 PM, Wilson Bilkovich wrote:

> On 10/22/06, Mike Durham <mdurham@people.net.au> wrote:
>> James Edward Gray II wrote:
>> > On Oct 22, 2006, at 7:30 AM, ilhamik wrote:
>> >
>> >> Thanks Peter, it works fine.
>> >
>> > You missed Tim Bray's RubyConf talk.  According to him we  
>> should, never
>> > be using the case changing methods.  "Just don't do it!"  ;)
>> >
>> > James Edward Gray II
>> >
>> Why not? What reason did he give?
>
> The problem is that proper upcasing and downcasing of characters is
> locale-dependent, not just encoding or language-dependent.

Yes, this is basically it.

Tim Bray feels that case changing is more or less impossible in the  
practical sense.  When you get around to downcasing that string a  
user entered into your web form a month back, are you going to know  
if that string was encoded in a Turkish local (critical info if it  
contains an "i")?

Even if it were possible, Tim suggests that it's a performance  
killer.  See Java, which tries to address as many rules as it  
possibly can, for proof.

James Edward Gray II