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Re: linking, 80/20

• To: Erik Wilde <net.dret@d...>
• Subject: Re: linking, 80/20
• From: Amelia A Lewis <amyzing@t...>
• Date: 20 Aug 2002 01:20:37 -0400
• Cc: xml-dev@l...
• In-reply-to: <3D617D51.8010404@d...>
• References: <r01050300-1015-31DC9E97B39911D69F470003937A08C2@[192.168.124.21]> <3D612F4B.9010703@d...> <1029785860.25933.71.camel@marajen> <3D61540E.4030504@t...> <1029791998.25933.89.camel@marajen> <3D617D51.8010404@d...>

On Mon, 2002-08-19 at 19:20, Erik Wilde wrote:
> i don't know sax too well, but shouldn't there already exist such a case 
> for 'attributes' and 'namespace attributes' of an element, so that when 
> an attribute declaring a namespace is being parsed, two events could be 
> raised? how does handle sax this?

A namespace declaration is not an attribute (even if DOM treats it like
one).  When you turn on namespace processing in SAX2, prefix mappings
are reported before the element that they appear on.  The thing that is
lexically an attribute in the XML is not reported as an attribute in the
start element event.

If namespace processing is enabled, then there are no prefix to
namespace mappings reported, and attributes may begin with the otherwise
reserved "xmlns" prefix.  This is also how SAX1 behaves.

> and yes, introducing infoset extensibility certainly would make any api 
> more complex, even though i think that the issues that were being raised 
> could be solved. and: if you didn't need or want access to the infoset 
> extensions, than you could still use a good old sax1/2 parser.

I don't believe that I made my point sufficiently clearly.  I think that
the infoset was designed to provide a full representation of the
interesting information in an XML instance.  Therefore, any additional
processing (such as the PSVI or the mooted XLink information items)
should be processed in a *different* layer.  Polluting the infoset is
not acceptable.  Adding a layer may be okay.

Keep in mind that once you add the layers, you immediately encounter a
problem of ordering.  Does schema validation happen before, or after
link information enhancement?  Note that the XQuery/XPath folks have
encountered this problem, and have declared that the XPath datamodel is
a transformation of the post-schema-validation infoset, which is itself
(in their discussion, last I checked) an enhancing transformation of the
infoset.  The infoset is left alone; order of processing is defined (but
note that this doesn't leave much room to add enhancements in different
directions, such as XLink).

The alternative, pushing the information items down into the infoset
itself, doesn't change the problem, it merely makes use of the infoset
as problematic as use of layers on top of the infoset currently is.

Amy!
-- 
Amelia A. Lewis       amyzing@t...      alicorn@m...
Tongue-tied and twisted, just an earthbound misfit, I.
                -- Pink Floyd

• Follow-Ups:
  • Re: linking, 80/20
    • From: Elliotte Rusty Harold <elharo@m...>
  • the infoset is two infosets (or even three?) [was: Re: linking, 80/20]
    • From: Erik Wilde <net.dret@d...>
  • Re: linking, 80/20
    • From: Erik Wilde <net.dret@d...>

• References:
  • Re: linking, 80/20
    • From: "Simon St.Laurent" <simonstl@s...>
  • Re: linking, 80/20
    • From: Erik Wilde <net.dret@d...>
  • Re: linking, 80/20
    • From: Amelia A Lewis <amyzing@t...>
  • Re: linking, 80/20
    • From: Tim Bray <tbray@t...>
  • Re: linking, 80/20
    • From: Amelia A Lewis <amyzing@t...>
  • Re: linking, 80/20
    • From: Erik Wilde <net.dret@d...>

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