xml-dev - Re: Options in XML 1.0

[Jonathan Borden <jborden@mediaone.net>]

Simon St.Laurent wrote:

>
> I'm not denying that these things are useful in certain cases, but I'm
> questioning whether the way they are implemented in XML 1.0 is sensible
> and/or safe.  I have no problem with 'pre-validation transformation',
> provided that it takes place in a clearly demarcated processing space and
> isn't jumbled with basic XML document reading.
>

Fortunately, or unfortunately depending on your perspective, XML 1.0 is
already specified and has been so for some time now. Like it or not DTDs are
a part of XML 1.0. Perhaps not XML 2.0, but I am not writing standards that
specify XML 2.0 yet, and until I can compare (the theoretical) XML 2.0
against the current XML 1.0 specification I can't make that distinction.

So like it or not, XML 1.0 specifies the procedure by which attributes are
defaulted in an internal subset and leaves parsing of the external subset
optional. It is true that depending on how a non-validating parser is
implemented, the same XML 1.0 document will produce different groves or
infosets. Many  sensible people prefer that a non-validating parser produce
the same grove or infoset as a validating parser and I for one would not use
a parser that did not produce the infoset I was expecting or changed the
infoset depending on whether the validation option is turned on or off.

Unfortunately for your position, part of the pre-validation transformation
that may occur during the parse phase (i.e. PE substitutions and attribute
defaulting) may indeed be 'jumbled with basic XML document reading' but this
is a well known and frequently used feature of XML 1.0. XML 1.0 conformant
parsers must support this. I agree with David Megginson as it was important
that the subsetting of SGML to form XML was associated with a distinct name
change (XML), that any subsetting of XML also be associated with a distinct
name change. For example CML or SML is less confusing than Common XML or
Simple XML and as with SGML and XML there is indeed no reason not to support
even more simple markup languages.

What is important is that we all agree on what XML 1.0 is, and given its
precise specification I think there is precious little room for argument
regarding this.

Jonathan Borden
The Open Healthcare Group
http://www.openhealth.org