RE: [xsl] XSLT/XPath 2.0: a USEFUL way to provide lexical info

["Matt G." <matt_g_ at hotmail dot com>]

>From: "Michael Kay" <michael.h.kay@ntlworld.com>
>Reply-To: xsl-list@lists.mulberrytech.com
>To: <xsl-list@lists.mulberrytech.com>
>Subject: RE: [xsl] XSLT/XPath 2.0: a USEFUL way to provide lexical info
>Date: Sun, 6 Jan 2002 20:01:00 -0000
>
>>I think, as a user, I'd rather see a "lexical" XPath axis
>>(pair?), to let me hop back & forth between the tree w/ the
>>lexical constructs and without.  I think this would be much
>>easier to use, and its use could be better encapsulated within a
>>small number of templates.
>
>It's a nice idea in principle, but I have some difficulty seeing
>how to flesh out the detail. The two main lexical components,
>entity references and CDATA sections, occur in the middle of
>character data, so it's not obvious how you would represent them on
>a separate axis.

Maybe I'm misunderstanding you, but I think the solution I was proposing is 
fairly straight-forward: preserve the same data model as in Appendix F of 
the 2001-12-20 XSLT 2.0 WD, but simply add an axis pair for hopping between 
two different trees--one which has the elements corresponding to lexical 
constructs, and the traditional one.  If you're already in the lexical tree, 
then the 'lexical-tree' axis does nothing, however the 'structural-tree' 
axis would take you back to a traditional view of the document.  Also, if a 
processor doesn't support this feature then both axes would do nothing.

For example, copying a tree fragment from the lexical tree should preserve 
the entity references.  I don't know whether you want to force the user to 
also manually create the entity definitions, in the result tree, or just 
have the processor be smart about copying definitions for which there are 
references.  Either is usable, and I imagine that when users are concerned 
about preserving entity references, they will simply copy all the entity 
definitions into the result tree.


Jeni is right that this would more than double the memory required to parse 
a document.  But so what?  Make it optional, and maybe processors will 
provide a switch to enable support for it, so you don't incur the overhead 
when you don't need lexical info.


Matt Gruenke


_________________________________________________________________
Join the world’s largest e-mail service with MSN Hotmail. 
http://www.hotmail.com


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list