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Are you sure the XML decl shouldnt be a PI ? :)

• From: "Richard Anderson" <rja@a...>
• To: <xml-dev@i...>
• Date: Sun, 14 Nov 1999 17:29:32 -0000

> [16] PI ::= '<?' PITarget (S (Char* - (Char* '?>' Char*)))? '?>'
> [17] PITarget ::= Name - (('X' | 'x') ('M' | 'm') ('L' | 'l'))
> The XML and text declarations cannot match this production -- the only
> reason that the syntax is similar is so that XML could work with
> legacy SGML tools.

Given the spec says PItargets starting with xml are reserved for
standazation in this or future versions of the spec, I'd personally say it
should be considered a PI with special meaning, why else reserve the
characters in the PI declartion ?  I can appreicate the SGML links (although
I've never used SGML) but it just seems strange to have exclusion clauses.
Also, the xml-stylesheet association is currently using a processing
instruction, so why no the XML decl too?  Dont tell, thats not a PI either,
or it will be called stylesheet declartion in the next XML spec  ;)

Another reason why I think it should be regarded as a PI...

If I using the DOM how do I specify the XML decl ? Using MSXML and other
implementations I've used  I create a PI and add it to the document, seems
very logical to me, so why confuse the issue ?

I know alot of Java people lwho don't use MSXML on this list, so please let
me know how you do it in your implementations.

> Please inform the author of the parser of this implementation bug.

I think it is a very useful feature, how else can I know the encoding ?
Using SAX 2 I guess we could add this as a feature using the URI techniques.
Still, I want the PI reporting in SAX1 so I'm happy to wonder from  the spec
for now if it achieves my goals and others.  Others must be happy with this
solution too, otherwise people wouldnt ever tools that dont conform.

> That book is also wrong -- please inform the author.

I cant see anywhere in the XML spec that says the XML dec is not a PI, or
vice-versa, so I don't feel compelled to do that just yet.  Maybe later
though when you hammer me with your next response ;)

Best Regards,

Richard.
----- Original Message -----
From: David Megginson <david@m...>
To: <xml-dev@i...>
Sent: Sunday, November 14, 1999 12:28 PM
Subject: The XML decl is not a PI (especially in SAX)


> "Richard Anderson" <rja@a...> writes:
>
> > The XML declaration is an indication to the application processing
> > the document as to what version of the XML spec the following markup
> > conforms to, what encoding is used, and whether or not there are
> > dependancies of external entites within the document.  All of those
> > are processing hints (read PI) for the XML processor, arent they ?
>
> Here are the productions for a processing instruction in XML 1.0:
>
> [16] PI ::= '<?' PITarget (S (Char* - (Char* '?>' Char*)))? '?>'
> [17] PITarget ::= Name - (('X' | 'x') ('M' | 'm') ('L' | 'l'))
>
> The XML and text declarations cannot match this production -- the only
> reason that the syntax is similar is so that XML could work with
> legacy SGML tools.
>
> > Certainly the SAX parser I use reports the XML declaration as a PI
> > which is obviously very usual.  Is that unusual ?
>
> That is wrong.  Note the documentation from DocumentHandler.java:
>
>     * Receive notification of a processing instruction.
>     *
>     * <p>The Parser will invoke this method once for each processing
>     * instruction found: note that processing instructions may occur
>     * before or after the main document element.</p>
>     *
>     * <p>A SAX parser should never report an XML declaration (XML 1.0,
>     * section 2.8) or a text declaration (XML 1.0, section 4.3.1)
>     * using this method.</p>
>
> Please inform the author of the parser of this implementation bug.
>
> > I will argue the XML spec doesn't define the declaration as a type
> > of PI, but it does reserve the xml PItarget, and, quickly checking
> > the nearest XML book on my desk (XML companion by Neil Bradley) that
> > also says it is a PI.
>
> That book is also wrong -- please inform the author.
>
>
> All the best,
>
>
> David
>
> --
> David Megginson                 david@m...
>            http://www.megginson.com/
>
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• Follow-Ups:
  • Re: Are you sure the XML decl shouldnt be a PI ? :)
    • From: David Megginson <david@m...>

• References:
  • Re: Separating documents in a stream
    • From: Eric Bohlman <ebohlman@n...>
  • Is the XML decl a PI ?
    • From: "Richard Anderson" <rja@a...>
  • The XML decl is not a PI (especially in SAX)
    • From: David Megginson <david@m...>

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