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

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

Hi Liam,

> The goal was to put SGML on the Web. It was difficult to use 
> SGML on the Web at the time. 

XML on the web is difficult, so I would say XML has fallen short of this
goal in at least one respect:  it's not a hypermedia format.  You don't have to get 100%
on the exam to be a success, so I'm not saying XML is a failure, but there's room for improvement.  

> The goal was not to replace HTML.
Which has a different goal than XML, obviously.

> 
> Peter - the short answer is that painting the railway engine 
> green won't make more people travel by train. There's no 
> single magic bullet. 

Fair enough.  Making XML into a hypermedia format involves more than links anyway.
But, if the base format does not have links, then only formats which derive from 
a format in the (derivation) tree which defines links will have links.  So the only formats
to have links in XML are those which use xlink.  Does XForms use xlink?  I'm not
saying it should, but to leverage software libraries which do implement links,
it might want to.

> There are barriers that could be lowered 
> a little, but there also has to be incentive, you have to 
> offer things that people already know they want.

I'm interpreting the paucity of support for xlink in XML clients to mean that
there is an unfulfilled need at the XML level.  That's just my interpretation
of course. 

> 
> For trains, it's a perception of a frequent and fast service 
> with no need to book a seat.
> 
> For computer formats it's making something easier than what 
> people currently do - not equally easy, but easier. 

Good point.  

Regarding xml:href, xml:rel and xml:type :

0) XML is not a hypermedia format - it needs links at a minimum to get up to that bar -
1) The XML namespace and its prefix are hardwired onto xml, and so offer an appealing point of entry for the sake of simplicity
2) Information models which don't specifically exclude such attributes appear to allow them
3) They don't prevent use of any other XML construct, as far as I can tell, including xlink.
4) "xml:type" has no equivalent in xlink - no typed links.  I think same for "xml:hreflang".  These aspects support the "Web" (REST) (I think).

Obvious continuing need to crowd-source the benefits and potential barriers. :-)


> > > If "mastery of the Web" _had_ been a goal, XML would have 
> been very 
> > > different, as Jeni Tennyson pointed out in her keynote at 
> XML Prague 
> > > this year.
> 
> I apologise to Jeni for the typo in "Tennison".
> 
> > Yes, I saw the video, but I forget this specific point.  
> Did she say 
> > how it would have been different?
> 
>   ``What might have been is an abstraction
>     Remaining a perpetual possibility
>     Only in a world of speculation.
>     What might have been and what has been
>     Point to one end, which is always present.''

:-)

Cheers,
Peter