Aleksander Slominski wrote:
>
> if you have more complicated links relations i think it is beneficial to
> define superset of atom:link and allow more powerful relations in
> decentralized way - i did it internally in my engine by using QNames,
> for example to point to internal topic (which is like "tag" or Wiki
> topic): <a href="/SomeTopic" rel="s:topic">...</a> that is later
> translated to <s:link rel="s:topic" xmlns:s="my-space"
> href="SomeTopic"/> where s:link is superset of atom:link with redefined
> rel/rev and other attributes possible.
>
> and for interoperability i can still of course generate <atom:link> in
> my atom feed (alas! i loose my custom relations as atom 1.0 has
> centralized rel content and does not allow namespace so for my own
> benefit i still include my own link el):
>
> <atom:link href="nytimes" title="Foo">
> <atom:link href="bbc" title="Bar">
> <atom:link rel="via" href="other-blogger" title="other" />
> <atom:link href="http://myspace/SomeTopic"/>
> <s:link rel="s:topic" xmlns:s="my-space" href="SomeTopic"/>

Why is this superset necessary? Atom supports decentralized definitions
of custom relations.

http://www.atomenabled.org/developers/syndication/#extensibility
http://www.atomenabled.org/developers/syndication/atom-format-spec.php#rfc.secti\
on.4.2.7.2

Here are a few examples of valid feeds:

http://feedvalidator.org/testcases/atom/4.1.1/link-rel-full.xml
http://feedvalidator.org/testcases/atom/4.2.7.2/absolute_rel.xml
http://feedvalidator.org/testcases/atom/6.4/link-extensions.xml

Note in the third example, there even are new attributes defined (in
their own namespace), and even elements placed inside the rel.

- Sam Ruby