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Re: namespaces redux (was: Re: [XML Schema]Here's ho

• From: Liam R E Quin <liam@w3.org>
• To: Andrew Welch <andrew.j.welch@gmail.com>
• Date: Tue, 16 Oct 2012 10:45:19 -0400

On Tue, 2012-10-16 at 09:34 +0100, Andrew Welch wrote:
> >> On 10/15/2012 12:09 AM, Liam R E Quin wrote:
> >> (in fact, best practices uses of W3C namespaces are not, ultimately, so
> > bad).

They might or might not be but I didn't write that. Actually I think
"best practice" is a term that often gets used in a way that is far from
helpful, even if that's not how it's being used in this thread, by
implying that anything else is "bad practice" and "wrong"...

> 
> Here are some namespace best practices for someone about create their
> own markup:
> 
> 1. Always use a prefix, never change the default namespace.
I'd say the opposite here.

> 2. Choose a namespace that will never, ever change - eg don't include
> version numbers or dates
"never" is a long time, and there are arguments on both sides, depending
on circumstance.

> 3. Avoid using URLs, the globally unique benefit is far outweighed by
> the confusion cost
A namespace URI is by definition a URI. Yes, you can use a URN, and I
think if URNs had been further along it might have been a better choice,
but there are plenty of reasons to use a URL, one of which is that some
(very broken) software thinks the namespace name points directly to a
W3C XML Schema document.

> 4. Keep it short, XPath 3.0 can include the namespace directly in the xpath
> 5. Use the standard prefixes for existing namespaces
> 6. Always declare all the namespaces on the root element
This last is also not always possible. For example, a SOAP system might
not know the prefixes declared in the payload in advance.

I think I'm with Tommie Usdin on this one, as she said in her Balisage
Keynote a little over a year ago, best practices aren't always best.

Liam

-- 
Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
Pictures from old books: http://fromoldbooks.org/
Ankh: irc.sorcery.net irc.gnome.org freenode/#xml
Co-author, 5th edition of "Beginning XML", Wrox, July 2012

• Follow-Ups:
  • Re: namespaces redux (was: Re: [XML Schema]Here's how to empower instance document authors to create their own root element)
    • From: Andrew Welch <andrew.j.welch@gmail.com>

• References:
  • [XML Schema] Here's how to empower instance document authors tocreate their own root element
    • From: "Costello, Roger L." <costello@mitre.org>
  • Re: [XML Schema] Here's how to empower instance documentauthors to create their own root element
    • From: Timothy Cook <timothywayne.cook@gmail.com>
  • Re: [XML Schema] Here's how to empower instance documentauthors to create their own root element
    • From: "Christopher R. Maden" <crism@maden.org>
  • Re: [XML Schema] Here's how to empower instance documentauthors to create their own root element
    • From: John Cowan <cowan@mercury.ccil.org>
  • Re: [XML Schema] Here's how to empower instance documentauthors to create their own root element
    • From: "Christopher R. Maden" <crism@maden.org>
  • Re: [XML Schema] Here's how to empower instance documentauthors to create their own root element
    • From: Liam R E Quin <liam@w3.org>
  • Re: [XML Schema] Here's how to empower instance documentauthors to create their own root element
    • From: "Christopher R. Maden" <crism@maden.org>
  • namespaces redux (was: Re: [XML Schema] Here's how toempower instance document authors to create their own root element)
    • From: Amelia A Lewis <amyzing@talsever.com>
  • Re: namespaces redux (was: Re: [XML Schema]Here's how to empower instance document authors to create their own root element)
    • From: Andrew Welch <andrew.j.welch@gmail.com>