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Re: Why associate an attribute with a namespace ?

• To: Michael Kay <mike@s...>
• Subject: Re: Why associate an attribute with a namespace ?
• From: mihaiu@m...
• Date: Wed, 16 Feb 2005 23:36:03 +0200
• Cc: xml-dev@l...
• User-agent: Internet Messaging Program (IMP) 3.2.2

>The rationale is to allow attributes whose semantics are independent of the
>element they appear on: examples are xml:lang, xml:base, xsi:type,
>xsl:version.
>

	The purpose of a namespace is to make it easier to avoid name collisions. The
special attributes that you speak about only need some kind to special syntax
in order to distinguish them from the others.

	Until now I have meet the following special attributes:

	a. xml:lang
	b. xml:space
	c. xml:base

	All are just a hint to the application. For example the xml:lang attribute
should be applied to the current element and its children. If the application
has some build-in support for this then the attribute will have a special
meaning, if not it will be just another std. attribute that has a meaning only
in the current element. Everything is just about interpretation. I could invent
right now an attribute called ?AllLowerCase? that would send a hint to the
application that all text in the current element and its children should be
converted to lowercase. It could be useful to be able to quickly recognize all
these special attributes that have a ?broad? scope. For that you only need a
special syntax like:

:AllLowerCase:
:lang:
:space:
:base:

or

.AllLowerCase.
.lang.
.space.
.base.

or

-AllLowerCase_
-lang_
-space_
-base_


	I hope that you understand me: there is no need for namespaces in this case
because namespaces are designed to solve a *completely* different set of
problems.



	One more thing: you said ?independent?. For mode clarity I will quote you
again:

>The rationale is to allow attributes whose semantics are independent of the
>element they appear on:

The attributes are not independent from the element containing them; they apply
to the containing element inclusively. For example the xml:lang attribute: if
this attribute is applied to a mixed content element then you expect that the
#PCDATA from the current element will respect the xml:lang attribute (not only
its children).



Regards,
Razvan



www.mihaiu.name

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