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Proposal about xmlns

From: Nathan <nathan@webr3.org>
Date: Thu, 10 Feb 2011 16:59:40 +0000
Message-ID: <4D54197C.9000303@webr3.org>
To: RDFA Working Group <public-rdfa-wg@w3.org>
CC: Manu Sporny <msporny@digitalbazaar.com>
Hi,

I'd like to propose that we remove the definition of xmlns:prefix 
(optional) from RDFa Core 1.1:

[[
xmlns:prefix (optional)
A method of declaring prefix mappings as defined in [XML-NAMES]. Prefix 
mappings declared via this attribute are equivalent to those declared 
using @prefix. If this attribute and @prefix declare a mapping for the 
same prefix on the same element, the mapping from @prefix must take 
precedence. Document authors should use @prefix, and should not mix 
@prefix and this attribute on the same element.
]]

and that we change step 4 of 7.5 (sequence) from:
[[
Mappings are defined via @prefix. For backward compatibility, some Host 
Languages may also permit the definition of mappings via @xmlns. In this 
case, the value to be mapped is set by the XML namespace prefix, and the 
value to map is the value of the attribute  a URI. Regardless of how 
the mapping is declared, the value to be mapped must be converted to 
lower case, and the URI is not processed in any way; in particular if it 
is a relative path it must not be resolved against the current base. 
Authors should not use relative paths as the URI.
]]

to:

[[
For backward compatibility, processors SHOULD recognize the definition 
of mappings via @xmlns. In this case, the value to be mapped is set by 
the XML namespace prefix, and the value to map is the value of the 
attribute  a URI. Regardless of how the mapping is declared, the value 
to be mapped must be converted to lower case, and the URI is not 
processed in any way; in particular if it is a relative path it must not 
be resolved against the current base.
]]

This is in order to further deprecate use of xmlns by authors in RDFa 
Core, whilst keeping backwards compatibility by encouraging processors 
to recognize prefixes defined via xmlns.

Hopefully this will further encourage best practise in RDFa 1.1, and 
address concerns by the HTML WG that we are still promoting use of xmlns 
and not deprecating it - by taking the same approach as them, one set of 
rules for authors, another for processors. This is also inline with the 
Robustness principle when writing internet standards.

Best,

Nathan
Received on Thursday, 10 February 2011 17:01:46 GMT

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