On Friday, February 4, 2005, at 02:05 PM, Tim Bray wrote:
On Feb 4, 2005, at 12:44 PM, Mark Nottingham wrote:That means that you're not allowed to sue the same atom:id in any two entries, ever.
I don't read it that way, although I understand how you might infer that; there's too much wiggle room in the current text for that intent to be clear.
I.e., just because it's a "permanent, universally unique identifier" doesn't mean you're not able to use it twice to talk about a single entry; to RDF people, this will seem quite natural. If you want to only see one instance of an atom:id's content in the set of all entries ever published in any feed, you need to say that explicitly.
I'm with Mnot on this one. Just because it uniquely identifies an entry, that doesn't mean you can't have two versions of the same entry in a feed. Given that entries can show up in more than one feed, it is clearly the case that software is going to have to deal with multiple entries bearing the same ID in its input stream, so I don't see any reason for ruling them out in a single feed.
But, the spec needs to have no wriggle room. Right now it's silent, it should be clear. -Tim
The following language should make things clear:
First, if we want to be able to put multiple revisions of an entry into a single Atom Feed Document (note: I'm talking about a document, not the abstraction called a feed), or multiple portions or versions of a feed into a single Atom Aggregation Document, if such a thing ever comes to exist:
"An Atom Document MAY contain multiple versions of the same resource, in which case the content of the Identity construct for each would be identical."
Second, if we don't want that to be possible:
"An Atom Document MUST NOT contain more than one version of the same resource. Thus, no two resources in a single Atom Document can have the same content in their Identity constructs."
