W3C home > Mailing lists > Public > public-awwsw@w3.org > February 2011

Re: Proposal, a new class of Web Names

From: Jonathan Rees <jar@creativecommons.org>
Date: Tue, 15 Feb 2011 08:31:05 -0500
Message-ID: <AANLkTin6a+EPapk+EerahVcZ2=OLu0yvmg5p-02UshnM@mail.gmail.com>
To: nathan@webr3.org
Cc: AWWSW TF <public-awwsw@w3.org>, Tim Berners-Lee <timbl@w3.org>
Let me see if I've got this:

The problem (in my restatement of what you said) is that different
people want to use dereferenceable URIs in different ways. In
interoperability scenarios they would be seen to be fighting over
ownership of linguistic territory, and the poor agent stuck in the
middle attempting to combine artifacts from the two sides (e.g. using
owl:imports) is going to get wrong answers.

So the solution is to retract httpRange-14 (and all the other specs
that say the same thing) - http://example/x instead of always meaning
the document always means the same thing that http://example/x# does,
and that's defined... how? According to 3986 you look at the media
type and go from there, so for HTML and XML it would mean an element
(which could never be defined since the empty string is not a valid
element id), and for RDF would be as 'defined' by the RDF.

This is nice for those who don't like # because it gives them a way to
write a # URI without writing the # character, and they don't have to
bother with 303. In fact I don't see how it differs from what Ian and
Harry are saying at all. Those of us who have been using
dereferenceable URIs to refer to documents are left in the cold and
would have to make up a new notation (see my TAG slides).

To me it would seem easier just to keep with httpRange-14 and say that
dereferenceable LOD URIs actually do refer to documents - specifically
nodes in the LOD network. The L in LOD  would be a
document-to-document relation which is what I think that community
wants. Maybe we say it privately among ourselves, but at least we
would have a consistent way to interpret combined OWL/LOD graphs.

I came up with the following yesterday in conversation with Manu
concerning use of # in RDFa: {Don't write <div id="foo" about="#foo">
if you're at all concerned that the element [see media type reg.] and
the thing you're calling #foo might have different properties - use
different fragids in that case.} If you don't care about inference
(your own or anyone else's) then of course it doesn't matter which you
do, so you're happy. If you do, you use different fragids and again
you're happy. Maybe the same approach would work with dereferenceable
URIs.

(1/2 cynical here, but want to explore options.)

Jonathan

On Mon, Feb 14, 2011 at 6:15 PM, Nathan <nathan@webr3.org> wrote:
> Hi Guys,
>
> Please do read over the following and let me know what you think - might be
> somewhat of a different approach ->
>
> [[[
>
> Problem Statement and Background.
>
> The Web has long since provided names as a way of referring to things, from
> time to time the specification of these names has had to be revised, in
> order to match their usage on the Web as it evolves.
>
> With the rise of the Semantic Web, Media Fragments and Web Applications, the
> usage of these names, especially http names, has changed to become either
> inconsistent with the current URI specification or their usage is simply
> unspecified.
>
> A side effect of this new usage, is that various communities have differing
> opinions on just what a URI can or does refer to, and on how those URIs can
> be used. This leads to tensions between communities which are trying to
> converge, and in the worst case threatens the evolution of those communities
> and their respective technologies.
>
> The web communities using these URIs share two common requirements, they
> need to use absolute URIs to refer to network accessible resources, and they
> require some form of indirect referencing, frequently turning to fragment
> identifiers for this purpose.
>
> One of the most contended uses of URIs, is when they are used to refer to
> abstract concepts or things evoked by the processing of representations, for
> example:
>
>  - A thing which is described within a representation, i.e. a person.
>  - A particular application state or recomposable view provided by the
> application.
>  - Some particular scene within a movie.
>
> Contentions are usually particularly high when a URI of the absolute-URI
> form is used for this purpose.
>
> In order to address this problem, it is suggested that a new class of Web
> Names is needed. A class which is disjoint with the current set of names
> (URIs/IRIs), fully compatible with those names, and which models existing
> naming conventions.
>
>
> Proposal - Web Names.
>
> Web Names provide a web friendly way of referring to things, each WebName is
> a 2-tuple comprising of a namespace and a name.
>
>  WebName  = ( namespace , name )
>
> The namespace part of a WebName takes the syntactic form of an absolute-IRI,
> the namespace typically refers to a network accessible resource.
>
> Each namespace has an infinite pool of locally scoped references, within
> different contexts there often exists a need to expose one of those
> references, for example:
>  - a reference to something which is described
>  - a reference to a particular state or information view
>  - a reference to a function or a variable
>  - a reference to a particular time sequence and area within a video
>
> The name part of a WebName provides a way to expose these indirect
> references, the name can take the syntactic form of the primary-ref (an
> empty string) or a reference (a string consisting of one or more
> characters), the name provides an anchor to refer to things named within a
> namespace.
>
> WebNames have the following syntax:
>
>  web-name     =  namespace local-name
>
>  namespace    =  absolute-IRI
>
>  local-name   =  [ "#" ] primary-ref / "#" reference
>
>  primary-ref  =  0<ipchar>
>
>  reference    =  1*( ipchar / "/" / "?" )
>
>
> Since WebNames are 2-tuples and IRIs are strings, the value space of
> WebNames is completely disjoint with the value space of IRIs, however, the
> lexical form of each WebName is also a valid IRI, as such:
>
>  IRI          =  http://example.com/foo/bar#baz1
>                  \________________________/ \__/
>                                  |           /
>  WebName      =             ( namespace , name )
>
> By sharing a lexical form which always produces a valid IRI, WebNames are
> fully compatible with the deployed web technologies, require no changes to
> be made, and are backwards compatible with existing IRIs which have been
> minted/used for the purpose of indirect referencing.
>
> Due to WebNames being 2-tuples, they cannot be dereferenced, this serves to
> null and void many of the most complicated and contentious issues outlined
> earlier, WebNames have been designed in such a way so that communities can
> opt-in to using them and focus on converging their technologies rather than
> trying to answer unanswerable questions.
>
> It is often the case that a network accessible resource is configured to
> provide information primarily about a single thing, for this purpose a
> WebName consisting of a namespace and a primary-ref can be used.
>
> When the name part of a WebName is the primary-ref, then the hash ("#") is
> optional, such that the WebName:
>
>  ( "http://example.com/foo/bar" , "" )
>
> can be specified using either of the following lexical forms:
>
>  http://example.com/foo/bar#
>  http://example.com/foo/bar
>
> and such that both those lexical forms encode the same WebName.
>
> ]]]
>
> Still needs work, especially on the text, but I think that's enough to get
> across what I'm proposing in the meantime. Thoughts and feedback more than
> appreciated.
>
> Best,
>
> Nathan
>
Received on Tuesday, 15 February 2011 13:31:39 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 15 February 2011 13:31:39 GMT