This is the mail archive of the
xsl-list@mulberrytech.com
mailing list .
RE: xml-stylesheet p.i. and other options
- From: "Chris Bayes" <chris at bayes dot co dot uk>
- To: <xsl-list at lists dot mulberrytech dot com>
- Date: Wed, 26 Jun 2002 13:13:09 +0100
- Subject: RE: [xsl] xml-stylesheet p.i. and other options
- Reply-to: xsl-list at lists dot mulberrytech dot com
Mike,
Hey don't worry. I don't think anyone is having a go at you. Just
discussing. I disagree with you but we can do that on this list without
anyone getting the hump.
I think pi's are the way to go because they are hints to the application
on how it should process the data. I agree that there could be a lot
better framework to handle all of theese multiple file situations but we
don't have one.
For schema they use schemaLocation which does adulterate the xml whereas
a pi is just a hint and comes in the preamble before the data proper.
Ciao Chris
XML/XSL Portal
http://www.bayes.co.uk/xml
> -----Original Message-----
> From: owner-xsl-list@lists.mulberrytech.com
> [mailto:owner-xsl-list@lists.mulberrytech.com] On Behalf Of Mike Brown
> Sent: 26 June 2002 11:02
> To: 'xsl-list@lists.mulberrytech.com'
> Subject: Re: [xsl] xml-stylesheet p.i. and other options
>
>
> David Carlisle wrote:
> > > such as when you've got no problem with the fact that your PIs
> > > might be ignored -
> >
> > Not agreed. saying that an application might ignore a PI is
> like saying
> > that an application may ignore <security level="top
> secret"> and publish
> > the information on the web. It's true, whatever the syntax is used,
> > elements, PIs lisp, ... it requires applications that read
> the syntax
> > and implement the specification of that syntax.
>
> Definitely not agreed.
>
> 1. An application is not required to take action on any
> processing instruction. The XML spec only requires that the
> application be
> made aware of the instruction's existence.
>
> "PIs are not part of the document's character data, but must
> be passed through
> to the application. The PI begins with a target (PITarget)
> used to identify
> the application to which the instruction is directed."
>
> (It is also suggested that you should use a Notation name as
> the target, so
> that your PI is essentially able to reference an application
> by a URI through
> that name)
>
> It is reasonable to infer from this that it is not even a
> requirement for
> an application to care about xml-stylesheet or any other
> target that it
> doesn't recognize.
>
> 2. The semantics of the xml-stylesheet PI are that there is
> an association
> made between the XML document containing the PI and the
> referenced stylesheet,
> nothing more. There's no requirement that an application
> processing the XML
> divine the intent behind the association, or take action upon
> it. So even if
> you feel that (1) is not true and that a PI can't be ignored,
> honoring the
> xml-stylesheet PI is pretty much a no-op, if the application
> wants it to be.
>
> > > when they're being applied to tie data to business logic;
> > > aapplications shouldn't be forced to fit the PI model.
> >
> > so business applications shouldn't specify their input
> using say dtd or
> > schema either both of which are only optionally read by a
> minimal XML
> > application (which needn't implement XSLT either).
>
> I don't follow exactly, but I think you're comparing apples
> and oranges. No,
> it's not harmful, but my argument can be applied here as well.
>
> I as the XML document author "shouldn't" assume, just because
> I've referenced
> a DTD or schema, that my application will receive validated
> input from the
> parser! Yet that's what I want/expect, so I've effectively imposed a
> requirement on the application developer to ensure that the
> application only
> gets its input from a validating parser.
>
> Even so, if I reference an external DTD or an XML Schema in
> my XML document,
> it does indeed come with a risk that it won't be processed
> (didn't someone
> recently say that Mozilla isn't reading external entities?),
> so I have to take
> that into account when I write my application. I certainly
> can't expect that
> my XML document will dictate that the application be smart
> enough to use a
> validating parser or a parser that resolves external entities.
>
> > Accepted that a lot of XML travels over the web in machine
> to machine
> > communication, for serving of XML over the web to browsers for human
> > consumption, I'd say the PI is currently the only option available.
> > (There are other options, such as server side
> transformation, but tehy
> > don't involve serving XML over the web)
>
> Those other options often do involve an HTML user-agent
> requesting XML,
> though, and getting back HTML. So while raw XML wasn't served, XML was
> requested, and a server-side application decided that the
> request should be
> interpreted as a request for the data within that XML,
> formatted in a manner
> more appropriate for that particular client. As I keep trying
> to say, this
> kind of decision and the determinations that go along with it
> (such as what
> the client's capabilities are and what an appropriate
> transformation would be,
> if any) is for the application to make. These needs are not
> very well-met by
> the PI approach at all.
>
> <sourGrapes>
>
> I'm very sorry I pushed this thread in this direction. I feel
> that I made the same statement as Michael Kay has made on the
> list more than
> once, even very recently -- that the xml-stylesheet PI and
> the paradigm it
> currently imposes (which is highly dependent on assumptions
> made about what
> clients will do) was generally not a good way to isolate data from
> presentation.
>
> Wendell Piez didn't disagree but challenged me to summarize
> what some of the
> alternatives were, so I started to list them but kept getting
> caught up in
> trying to (over-)explain under what circumstances you'd want
> to use those
> options. I finally posted my take on the situation, my
> rationale for believing
> xml-stylesheet is harmful, and why I felt so strongly about
> it. My rationale
> may not be the same as M.H.Kay's, but it led me to
> approximately the same
> conclusion. Yet now I have nary a sympathetic ear, and Kay
> hasn't offered his
> 2 cents at all, so I look like an idiot and a troll.
>
> </sourGrapes>
>
> - Mike
> ______________________________________________________________
> ______________
> mike j. brown | xml/xslt: http://skew.org/xml/
> denver/boulder, colorado, usa | resume:
> http://skew.org/~mike/resume/
>
>
>
>
> XSL-List info and archive:
> http://www.mulberrytech.com/xsl/xsl-list
>
>
XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list