Re: Proposal about xmlns

I agree.

Ivan

On Feb 10, 2011, at 17:59 , Nathan wrote:

> 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
> 


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Ivan Herman, W3C Semantic Web Activity Lead
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