Re: PRISM and RSS

[Aaron Swartz <aswartz@swartzfam.com>]

David Smiley <dsmiley@mitre.org> wrote:

> The specs at W3C are pretty harry.

I certainly agree with you there -- my goal is to help make them simpler.

>> I like PRISM a lot, but RSS 1.0 is simpler.
> "Simpler" is subjective... I think there is more to their spec than
> RSS 1.0, but you don't have to use what you don't need.

But you do have to decide whether you need it or not.

>> And neither is "more RDF based" than the other.
> RSS 1.0 uses "item" tags to describe news items and the "channel" tag
> to denote the channel.  In PRISM, they are all rdf:Description.  Why
> doesn't RSS 1.0 use rdf:Description?

Two reasons:

 - rdf:Description has no semantics -- it's just a piece of syntax to say
"I'm talking about something now". Using an item tag, however, lets RDF
processors know "this here is an rss:item".

 - Backwards compatibility.

> Also, I see tags like "title"
> and "link" in an RSS 1.0 document.  By convention, the rdf:about
> attribute is "link", so why the redundancy?

This one has a good reason:

 - <link> has long been used to refer to a URL where a document can be
accessed. However, some CMSes break links for some reason (bad!) and there
are sometimes many items which all have the same URL. rdf:about provides a
place for a permanent, unchanging identifier. By convention, it's the same
as link, because that seems the most obvious identifier. However, if link
needs to change for some reason, rdf:about should not.

(Note that this is my opinion, not a decision of the Working Group's.
However, this usage is fully compatible with the spec.)

Oh yeah, and backwards compatibility.

>  Why "title" in the RSS
> 1.0 namespace when there is one of the same name in the Dublin Core
> namespace?  These things strike me as RSS 1.0 "doing its own thing"
> and deviating from more standard compliance.

Yes, this one we really can't justify, except backwards compatibility.
However, to make up for it, we've stated in the schema that rss:title is a
subClassOf (can be used as) a dc:title. This should help schema-capable RDF
processors deal with the difference.

> There's a lot of wheel re-inventing in computer science, and I'm
> trying to nip-this one in the butt.

I hope that you can see that the RSS 1.0 WG cared a lot about RSS and
compatibility. That's why we made all of these sacrifices for
backwards-compatibility. We wanted to add power and extensibility to RSS --
RDF already has it.

-- 
[ Aaron Swartz | me@aaronsw.com | http://www.aaronsw.com ]