Re: Proposal: deprecate mod_link (was Re: Re: multiple Links)

"Randy Morin" <[email protected]> writes:

> What's the alternate (pun) solution? How would you do a generic
> <link> in rss1.0?

Take a look at the bottom of Aaron's reply,
    http://groups.yahoo.com/group/rss-dev/message/4325

Aaron wrote:
AS>   Please recast it as RDF. Your example:
AS>    <l:link l:rel="http://purl.org/rss/1.0/modules/link/#alternate"
AS>      l:type="application/rss+xml"
AS>      l:title="What's New on Example (French)"
AS>      l:lang="fr"
AS>      rdf:resource="http://www.example.org/index-fr.rss"/>
AS>   should be:
AS>    <l:alternate rdf:resource="http://www.example.org/index-fr.rss"
AS>      dc:format="application/rss+xml"
AS>      dc:title="What's New on Example (French)"
AS>      dc:language="fr" />

I'm gonna try to stay out of the abstract and stick with the concrete,
which "hides" some concepts that might give an "Aha!" but also might
make things ramble.

I do, however, have to explain, in RDF terms, why even the *model* of
the Link module is wrong.

First, a basic RDF link:

  <atom:service.feed rdf:resource="http://example.org/feed.atom"/>

This indicates that the RDF subject (not shown, just assume it's the
resource this property is attached to) has a "feed" property, and that
representation of the "feed" property resource is at 'feed.atom'.  We
know this because that's the definition of atom:service.feed
documented somewhere else.

Every other bit of XML within that element or its children is about
the linked resource, 'feed.atom'.  That's because the above syntax is
a shorthand for,

  <atom:service.feed>
    <rdf:Description rdf:about="http://example.org/feed.atom"/>
  </atom:service.feed>

After its basic premise (RDF doesn't have links), the second biggest
problem with the Link module is that it presumes that the properties
l:title, l:rel, l:type are about the *link* (the property), when the
RDF model says they are about the resource *referenced* by the
property (the object URI).  Literally, the above Link example
translates to:

  <l:link>
    <rdf:Description rdf:about="http://www.example.org/index-fr.rss">
      <l:type>application/rss+xml</l:type>
      <l:title>What's New on Example (French)</l:title>
      <l:lang>fr</l:lang>
      <l:rel>http://purl.org/rss/1.0/modules/link/#alternate</l:rel>
    </rdf:Description>
  </l:link>

Here, l:type, l:title, and l:lang actually look quite appropriate as
properties of 'index-fr.rss'.  It's the l:rel that is out of place,
because it's not a property of 'index-fr.rss', but somehow a property
of the l:link from the subject (channel) and 'index-fr.rss'.

So, if we switch that around and use the relation as the property
name, add in reusing existing vocabularies, and you get the
alternative.

  <atom:service.feed>
    <rdf:Description rdf:about="http://www.example.org/index-fr.rss">
      <dc:format>application/rss+xml</dc:format>
      <dc:title>What's New on Example (French)</dc:title>
      <dc:language>fr</dc:language>
    </rdf:Description>
  </atom:service.feed>

Noting the shorthand mentioned earlier, this is also:

  <atom:service.feed rdf:resource="http://www.example.org/index-fr.rss"
    dc:format="application/rss+xml"
    dc:title="What's New on Example (French)"
    dc:language="fr" />

Every relation in RDF is a generic link, and like the 'rel' attribute
in Atom and HTML, it's the property name that tells you what you can
do with the relation.

  -- Ken

P.S.  I understand that a follow-on discussion could happen about what
constitutes a "generic link", but the protracted discussion on
atom-syntax resolved that there's no such thing as a "generic link",
it's just that some people feel more comfortable "extending" a syntax
at a bottlneck point where they believe they don't have to create a
namespace or URI and new XML elements.  RDF says, "get past it, it's
simpler when you do".


 
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