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Re: ID Characters (was: Re: 3.4. Global attributes)

From: Jim Jewett <jimjjewett@gmail.com>
Date: Thu, 2 Aug 2007 12:55:41 -0400
Message-ID: <fb6fbf560708020955y102b9ad6mf5ef2bc0ad627f14@mail.gmail.com>
To: "Robert Burns" <rob@robburns.com>
Cc: public-html@w3.org

On 8/2/07, Robert Burns <rob@robburns.com> (edited by rewording to) write:
> On Aug 1, 2007, at 5:04 PM, Jim Jewett wrote:

> > "Note: Authors should be aware that some [legacy] tools may not
> > handle all IDs properly.
> > For maximum compatibility, authors should use IDs starting with an
> > ASCII letter, containing only ASCII letters and numbers, and
> > containing only a single case (upper or lower) of letter."

> That's fine. I prefer using the term legacy tools for rhetoric
> effect. As far as I'm concerned any tool that's processing HTML or
> XML that is Unicode unaware is a legacy tool: even if it's created
> ten years from now.

That works for me; I would think of them as buggy rather than legacy,
but it is a bug magnet that won't go away.

(People can stop reading now; I answer his other questions, but the
summary is "Works For Me")

> On these issues (especially containing only a single case), could you
> provide some examples of tool that have problems. Not that we're
> going to include in the recommendation, but it would be helpful for
> us to have research citations backing up notes like this.

The situation that annoyed me most recently is part of an internal web
site; some scripts compare case sensitive, and others don't.  Most
authors leave ID tags alone, but someone edited a template, changed
case on attributes (which worked fine in what they looked at) and
broke some stuff downstream.

I'm not inclined to argue about whether this was sensible, but it
happens; I doubt the "Are namespaces case-sensitive?" question will
ever be fully resolved, and so people will make mistakes, regardless
of which answer is correct.

> The legacy tools part I was simply referring to the Unicode problems
> and the case (-folding?) problems

And my point is that Unicode and case-folding will continue to be
bug-magnets for at least the next decade (probably century), so author
recommendations for inter-operability ought to be conservative in what
they emit.

-jJ
Received on Thursday, 2 August 2007 16:55:43 GMT

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