RE: [xsl] Infinite Loop when param empty

["Michael Kay" <mhk@xxxxxxxxx>]

I have not come across a case where it makes sense for a tree-valued
parameter to have any default value other than the empty sequence.
Defaulting it to a node in the principal source document, whether this is
the root node or the outermost element, seems an odd thing to do.

Michael Kay 

> -----Original Message-----
> From: Karl J. Stubsjoen [mailto:karl@xxxxxxxxxxxxxxxxxxxx] 
> Sent: 22 July 2004 23:56
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject: RE: [xsl] Infinite Loop when param empty
> 
> Thanks for the input on the "Infinite Loop".
> Is it good practice to explicitly ask for the top level element in the
> select property?  So, the xml source being passed in may look like:
> 
> <XML_SOURCE>
>   <XML_DATA/>
>   <XML_DATA/>
>   <XML_DATA/>
> </XML_SOURCE>
> 
> And the parameter looking like:
> <xsl:param name="ENTRY_TEMPLATE" select="XML_SOURCE"/>
> 
> Karl
> 
> 
> 
> -----Original Message-----
> From: Michael Kay [mailto:mhk@xxxxxxxxx]
> Sent: Thursday, July 22, 2004 3:02 PM
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject: RE: [xsl] Infinite Loop when param empty
> 
> 
> > I have a param which is populated with an XML source.
> >
> > The paramter is declared like this:
> > <xsl:param name="ENTRY_TEMPLATE" select="/"/>
> >
> > My top level match is:
> > <xsl:template match="/">
> >
> > Within this template rule I apply the following:
> > <xsl:apply-templates select="$ENTRY_TEMPLATE"/>
> >
> > If the param ENTRY_TEMPLATE is not set, I end up with an
> > infinite loop.  Is
> > this normal behaviour?  I'm guessing that maybe it is bad 
> practice to
> > declare the param as I have.
> 
> Yes, the system is behaving correctly - it is doing exactly 
> what you asked
> it to do. And yes, it might be a good idea to ask it to do something
> different!
> 
> Michael Kay