RE: [xml-dev] xml:href, xml:rel and xml:type

["Rushforth, Peter" <Peter.Rushforth@NRCan-RNCan.gc.ca>]

Hi Len,

The scope for these attributes is web linking.  I can see that there should
be a strict constraint on what gets put into the xml namespace.  xml codifies
a very few but very important things. xml:lang, xml:base and a couple of others.

My point of view on this is that html is "big" because it is static and shared.  xml needs
a bit of this static shared stuff to make it more amenable to certain uses.  Goal #1 of XML
was to be simple to use on the web.    To be simple to use,
it needs to have some static, reliably present markup which can be acted on.

Web crawlers, to take one example, can't crawl xml, because there is no reliable static
markup to identify links in all xml.  The existence of xml:href solves that problem.
Unless they are Kreskin crawlers they won't know what to do with the xml when they find it.
That is what @xml:type is there for.  While application/xml does not tell you too
much, there are sub sub media types, media type parameters etc to tell you how
to process the representation once you retrieve it.  Also, it does not have to be xml :-).

Finally, applications which use xml on the web need a way to decide / let the
client decide what state is the next state for the client.  That is what @xml:rel 
is for.

How is this different from xlink?  For one thing, it is static shared markup that
can be reliably used by the entire community.  For another, xlink:type and xml:type are
different. xlink:type describes the processing of the link, while xml:type advertises
the media type that may be negotiable from the server (no guarantees, after all its
the server's resource). 

Why is xml:lang needed for xml itself?  or xml:base for that matter?  Why is linking less important?

Cheers,
Peter

> -----Original Message-----
> From: Len Bullard [mailto:cbullard@hiwaay.net] 
> Sent: April 16, 2012 21:03
> To: Rushforth, Peter; 'Simon St.Laurent'
> Cc: liam@w3.org; xml-dev@lists.xml.org
> Subject: RE: [xml-dev] xml:href, xml:rel and xml:type
> 
> Not to worry, Peter.  We've practiced. :)
> 
> Essentially, xml:href adds application semantics to the XML 
> specification.
> XML abhors application semantics in its specification.  Adding those
> violates the simplicity constraint.   Application 
> specifications are free to
> do that.  IOW, you are asking the wrong list.  Or maybe not, 
> but the point is, XML doesn't specify XML applications past 
> what is needed for XML itself.
> 
> 
> Functional specifications for inter XML linking are a snap.  
> Functional linking to other media types is built into the web.
> 
> What is the scope for xml:href linking and how does that 
> differ from what is currently possible with previously 
> specified technologies?
> 
> One compelling argument for functionally-spec'd XML is 
> authoring common document type collections, eg, TOCs, typed 
> indices, figure/table
> collections, etc.   Tbese are human cultural notation types.  
> Building those
> into a system for use by humans is never wrong, IMHO.
> 
> len
> 
> 
> 
> -----Original Message-----
> From: Rushforth, Peter [mailto:Peter.Rushforth@NRCan-RNCan.gc.ca]
> Sent: Monday, April 16, 2012 6:55 PM
> To: Len Bullard; Simon St.Laurent
> Cc: liam@w3.org; xml-dev@lists.xml.org
> Subject: RE: [xml-dev] xml:href, xml:rel and xml:type
> 
> Not to  preach, but I have always felt that respect for what 
> has been achieved is a good place to start any conversation.
> 
> I am merely asking why some simple steps can't be taken to 
> move the yardsticks a bit.  Not any steps:
> the steps I am proposing.
> 
> Cheers,
> Peter
> ________________________________________
> From: Len Bullard [Len.Bullard@ses-i.com]
> Sent: April 16, 2012 4:36 PM
> To: Simon St.Laurent; Rushforth, Peter
> Cc: liam@w3.org; xml-dev@lists.xml.org
> Subject: RE: [xml-dev] xml:href, xml:rel and xml:type
> 
> And so it begins.
> 
> The early HTML people disdained SGML as overbuilt and too 
> hard to understand because they had yet to understand how and 
> why it worked for the applications to which it had been 
> applied.  The SGML people returned the disdain but helped them anyway.
> 
> Some decades on, as predicted, attempts to reinvent the early 
> work on hypertext by the SGML community that evolved into the 
> XML community continue.  At this point, everyone shares A 
> working system so those
> attempts have yet to produce a compelling case.   It is somewhat as if
> once shown that a Ford A-model could double as a truck, no 
> one needed anything better.  Cab heat would be nice but who 
> wants to put the fur traders out of business?
> 
> Why no xml:href?   How many systems does it take to change a 
> light bulb?
> No one cares while the bulb is lit.
> 
> Why bolt a function-type system onto a syntax standard?  
> (Linking is a process; not data).
> 
> len
> 
> -----Original Message-----
> From: Simon St.Laurent [mailto:simonstl@simonstl.com]
> Sent: Monday, April 16, 2012 3:15 PM
> To: Rushforth, Peter
> Cc: liam@w3.org; xml-dev@lists.xml.org
> Subject: Re: [xml-dev] xml:href, xml:rel and xml:type
> 
> 
> The early XML folks may have found HTML to be not what they 
> wanted, and seriously lacking in many respects, and the 
> people driving the HTML conversation today return the disdain
> 
> 
> What a misfire!
> 
> 
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