Re: Proposal about xmlns

I agree that this approach is a very sensible accommodation of past
practice while pointing people in the right direction. -Sebastian

On Thu, Feb 10, 2011 at 11:59 AM, Nathan <nathan@webr3.org> 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
>
>