Re: Re: [xml-dev] SAX Topic 2004-0002: XML 1.1 support

Neil Graham <[email protected]> Thu, 26 Feb 2004 19:21:38 -0500

Newsgroups	gmane.text.xml.sax.devel,gmane.text.xml.devel
Message-ID	<[email protected]>

Hi all,

Sorry about joining the fray late; I have only one thought I figured might
be worth sharing.

Elliotte wrote, in responding to David Megginson:

[[
>- add a read-only feature to check for XML 1.1 support (John Cowan,
> 2004-02-18)
>

I suggest this should be read-write for parsers that support XML 1.1.
I have a need to sometimes require documents to be 1.0, and right now
setting that up with a parser that supports 1.0 is a royal PITA.

]]

I'd point out that, once you have the Locator2 interface at your disposal,
it will no longer become a PITA of any class--you simply look at the output
of getXMLVersion(), and if you don't like what you see, just throw a
SAXException.

I'm also a little worried about how this feature plays with
future-proofing. So we now have a way to disable XML 1.1 support; if an
XML 2.0 comes along, do we have another feature to disable that? In view
of how long it's taken before the 2.0 Extensions were fully baked and ready
to come out of the oven, I worry about having to reopen these Pandora's
boxes years from now--even setting aside how unpleasant profusions of
features tend to be for users.

So would it be better to have a property for disabling XML versions? I
guess you could specify a whitespace-separated list of version tokens as
values; at least it would be future-proof.

All in all though, with Locator2 nearly here, it seems to me like any kind
of complication in the API to support this use-case is hard to warrant. I
just can't imagine many garden-variety applications needing it.

Cheers!
Neil
Neil Graham
XML Parser Development
IBM Toronto Lab
Phone: 905-413-3519, T/L 969-3519
E-mail: [email protected]

Elliotte Rusty Harold
<[email protected]> To: David Megginson <[email protected]>
Sent by: cc: XML Developers List <[email protected]>,
[email protected] [email protected]
ceforge.net Subject: [Sax-devel] Re: [xml-dev] SAX Topic 2004-0002: XML 1.1 support

02/22/2004 10:36 AM

At 9:27 AM -0500 2/22/04, David Megginson wrote:
>* Topic 2004-0002: XML 1.1 support
>
>- add a read-only feature to check for XML 1.1 support (John Cowan,
> 2004-02-18)
>

>- add a read-only property (double) to return the version number of
> the document being parsed (John Cowan, 2004-02-18)

I suggest that this property be a String rather than double. Several
reasons:

1. Long term, it may not always be parseable as a double (1.1.1 anyone?)
2. Double equality comparisons are very tricky. String comparisons
are much simpler.
3. It's not hard to convert a String to a double if you need that for
some reason.
4. It's not really possible to make the value of the property a
primitive double in Java. It would have to be a Double. Better to
just make it a String, which is a little easier to deal with in code.

Elliotte Rusty Harold
[email protected]
Effective XML (Addison-Wesley, 2003)
http://www.cafeconleche.org/books/effectivexml

http://www.amazon.com/exec/obidos/ISBN%3D0321150406/ref%3Dnosim/cafeaulaitA

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