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Posted to dev@xalan.apache.org by zo...@ca.ibm.com on 2003/02/21 17:28:16 UTC

Question about Xalan-specific xsl:output attributes

Hello,

     The other day I was looking at section 2.1 of XSLT 1.0 [1].  It 
states in part that "An element from the XSLT namespace may have any attribute not from the 
XSLT namespace, provided that the expanded-name of the attribute has a 
non-null namespace URI. The presence of such attributes must not change 
the behavior of XSLT elements and functions defined in this document." The 
same text appears in section 3.1 of XSLT 2.0.

     Does anybody know how to reconcile that text with the behaviour of 
xsl:output attributes, such as xalan:use-url-escaping and 
xalan:omit-meta-tag?  In a case like xalan:indent-amount, there's no 
*real* change in behaviour, but in the other two cases I've mentioned, 
there is.  Any opinions about this?

Thanks,

Henry
[1] http://www.w3.org/TR/xslt#xslt-namespace
------------------------------------------------------------------
Henry Zongaro      Xalan development
IBM SWS Toronto Lab   Tie Line 969-6044;  Phone (905) 413-6044
mailto:zongaro@ca.ibm.com

Re: Question about Xalan-specific xsl:output attributes

Posted by Joseph Kesselman <ke...@us.ibm.com>.
Just to make sure we're on the same page: Stylesheet elements in the xsl: 
namespace (OK, you know what I mean!) can carry attributes not defined by 
the XSLT Recommendation, as long as those attributes aren't in the xsl: or 
default namespaces (to keep them from colliding with names reserved for 
XSLT's use). Those additional attributes should have no effect on XSLT 
processing per se. From XSLT's point of view, they will be  ignored. But 
they *MAY* have effects which do not affect compliance with XSLT's 
definition. "Such attributes can provide, for example, [...] optimization 
hints [...]"

As Henry noted, Xalan takes advantage of that flexibility to support a few 
custom features 
(http://xml.apache.org/xalan-j/usagepatterns.html#outputprops). These 
aren't "optimizations", but I think one can argue that they fall in the 
same category.

Some of them *may* be departures from the Recommendation. 

BUT:
* Having them available on <xsl:output> as "extensions attributes" is 
certainly no worse a departure than having them, and the other 
configuration features, available at the processor configuration level via 
the Properties file.
* And they *ONLY* take effect on stylesheets which have explicitly 
requested them, unlike the Properties change.
* And they really don't break the world any worse than any other Extension 
can and does.

MOVED: 
1) That we document these as Built-In Extension Attributes, with all the 
same issues as other Extensions
2) And that we admit that the concept of Extension Attribute, while 
architected in the XSLT Recommendation, is not well-defined there.
3) And that we send a formal request to the XSLT Working Group that this 
concept be nailed down more explicitly in XSLT 2.0.

______________________________________
Joe Kesselman  / IBM Research


Re: Question about Xalan-specific xsl:output attributes

Posted by David N Bertoni/Cambridge/IBM <da...@us.ibm.com>.



Hi Henry,

Actually, it doesn't change the behavior of any elements or functions.  It
affects serialization, which is not an element or function, and isn't even
required for conformance, so I think we're OK.

Dave



                                                                                                                                        
                      zongaro@ca.ibm.c                                                                                                  
                      om                       To:      xalan-dev@xml.apache.org                                                        
                                               cc:      (bcc: David N Bertoni/Cambridge/IBM)                                            
                      02/21/2003 08:28         Subject: Question about Xalan-specific xsl:output attributes                             
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                      to xalan-dev                                                                                                      
                                                                                                                                        



Hello,

     The other day I was looking at section 2.1 of XSLT 1.0 [1].  It
states in part that "An element from the XSLT namespace may have any
attribute not from the
XSLT namespace, provided that the expanded-name of the attribute has a
non-null namespace URI. The presence of such attributes must not change
the behavior of XSLT elements and functions defined in this document." The
same text appears in section 3.1 of XSLT 2.0.

     Does anybody know how to reconcile that text with the behaviour of
xsl:output attributes, such as xalan:use-url-escaping and
xalan:omit-meta-tag?  In a case like xalan:indent-amount, there's no
*real* change in behaviour, but in the other two cases I've mentioned,
there is.  Any opinions about this?

Thanks,

Henry
[1] http://www.w3.org/TR/xslt#xslt-namespace
------------------------------------------------------------------
Henry Zongaro      Xalan development
IBM SWS Toronto Lab   Tie Line 969-6044;  Phone (905) 413-6044
mailto:zongaro@ca.ibm.com