Re: Component interfaces

Erik Bruchez wrote:
 >
> An XSLT stylesheet is an XML document like any other, and there are
> uses cases where you may want to dynamically produce an XSLT
> stylesheet from other pipeline steps. Our experience with XPL has been
> that considering that components take only XML documents as inputs and
> outputs, and not special-casing things like stylesheets or other
> parameters, simplifies the language a lot while making it more
> powerful.
> 
> For reference, this is how executing an XSLT transformation can be
> done with XPL [1]:
> 
> <p:processor name="xpl:xslt">
>   <p:input name="stylesheet" infosetref="my-stylesheet.xsl"/>
>   <p:input name="data" infosetref="my-document.xml"/>
>   <p:output name="data" infoset="my-result"/>
> </p:processor>

I've thought a bit more about this issue. I agree with you, regarding 
the XSLT processor. However, requiring infosets as inputs is a problem: 
if you have an XQuery processor, your approach would require queries to 
be written in XQueryX [1]; if you have a Relax NG schema, compact syntax 
would not be allowed; a hypothetic SQL processor would require queries 
to be wrapped into an XML envelope.

While all these issues can be handled with infosets, I'm sure that we'll 
get a lot of pushback from the community. I believe it's another issue 
we'll have to take into account when defining XProc's data model.

Cheers,

Rui


[1] http://www.w3.org/TR/2005/WD-xqueryx-20050915/