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Re: Summary of @href/@resource completing triples issue

From: Niklas Lindström <lindstream@gmail.com>
Date: Thu, 10 Jan 2008 01:56:32 +0100
Message-ID: <cf8107640801091656r72cebdc2sc098e689ddff5392@mail.gmail.com>
To: "Mark Birbeck" <mark.birbeck@x-port.net>
Cc: "Ben Adida" <ben@adida.net>, "Manu Sporny" <msporny@digitalbazaar.com>, RDFa <public-rdf-in-xhtml-tf@w3.org>

Hi Mark,

you're starting to convince me. Indeed, that hanging rels can be risky
since it affects a lot of nested content is reasonably true, but that
mostly suggests to properly warn about using it without care. It
surely shouldn't turn up by accident, and I suppose it isn't much more
powerful than @about (and @resource, @href, @src) already are, since
they permeate the meaning of nested content as well.

I hope the following is good to spell out, since my understanding of
it became much clearer now.

> I admit that there were many situations where your approach was
> useful, but ultimately the behaviour was just too inconsistent to be
> workable. My proposal was to simply say that @instanceof should
> *always* apply to the subject of the current context, regardless of
> how that subject was obtained...via @about, the bnode on @instanceof,
> and yes, even a lone @resource.

I take it this means that you consider that:

    <div resource="#section" instanceof="ex:Section">

should yield:

    <#section> a ex:Section .

But, from your arguments such as:

> but now you seem to be implying that you would not be happy with this:
>
>   <div resource="A" instanceof="t">
>     <div rel="p" resource="B" />
>   </div>
>
> You seem to think this to be strange, whilst I see it as consistent
> with the idea that 'the subject' can be set in various ways, and
> @instanceof always applies to 'the subject' of the current context.

I gather that this:

    <div rel="ex:section" resource="#section" instanceof="ex:Section">

does *not* yield:

    <> ex:section <#section> .
    <#section> a ex:Section .

but:

    _:x ex:section <#section> .
    _:x a ex:Section .

, since with the @rel present the @resource *works to complete a
statement* (acts as object), here with a bnode as subject from
@instanceof. (I admit I hadn't properly understood this until now.)

(It's also true I gather that thinking of @instanceof as a shorthand
for (also) putting a <span rel="rdf:type" ...> as first nested child
is not at all the idea (and consensus) today, right? To avoid the
complex "jumping" effects.)

It furthermore seems that, if all this is accepted, having:

    <img src="me.jpg" instanceof="foaf:Image" />

would produce:

    <me.jpg> a foaf:Image .

regardless of @src behaving as @about or @resource, correct? But
again, not if a @rel is present in <img>, for which only the @about
case yields an expected result (if @src as @resource, we'd have a
bnode foaf:Image with some relation (from @rel) to that).


(Unfortunately for me, my "content and parts" problem still stands in
the light of this, but that's another thread of course. While perhaps
my (ab)use of @role there could be made to work, or even adding some
form of "@instanceof companion" (revival of @resourcetype, anyone?) to
type the current object. But I admit that I am a bit reckless in
suggesting this stuff. If at all, it belongs in the other thread).

Best regards,
Niklas
Received on Thursday, 10 January 2008 00:56:38 GMT

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