RE: [xsl] Filtering XML elements based on tokenized external parameters?

["Aron Bock" <aronbock@xxxxxxxxxxx>]

Ramon,

You'll probably get many suggestions on approaching this as you describe -- 
pass in XSL parameters, and have the main stylesheet figure out what to 
emit.

I'm writing to propose an alternative -- especially since you may use a 
script to glue together things, the school of thought that has programs 
writing programs would have you consider writing a script or transform that, 
given your input "parameters", would then automatedly and dynamically 
construct a special-purpose XSL stylesheet that, applied against your 
original input XML, would output the nodes you want.

Regards,

--A

> From: "Ramon Felciano" <felciano@xxxxxxxxxxxxx>
> Reply-To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> To: <xsl-list@xxxxxxxxxxxxxxxxxxxxxx>
> Subject: [xsl] Filtering XML elements based on tokenized external 
> parameters?
> Date: Fri, 17 Jun 2005 09:44:00 -0700
>
>
> Hello --
>
> I'm trying to do parameterized XSLT-based filtering to strip out
> unwanted structure from an XML file. The XML file represents a graph
> data structure along with some other metadata. Conceptually I want to
> extract a subgraph from this data structure, but want to do so in an
> upwards-compatible way such that any additional tags in the XML are
> carried over to the resulting document. For example, given this XML
> file:
>
> <graph>
>     <node id="alpha"/>
>     <node id="beta"/>
>     <node id="delta"/>
>     <node id="gamma"/>
>     <edge from="alpha" to="delta"/>
>     <edge from="alpha" to="beta"/>
>     <edge from="alpha" to="gamma"/>
>     <edge from="beta" to="beta"/>
>     <mymetadata id="123"/>
> </graph>
>
> Given the above simple graph data structure, I want to produce a
> filtered version that only includes node elements (ideally both node and
> edge elements) that match a given set of input parameters, as well as
> any other tags that might be included (e.g. the mymetadata tag). I'd
> ideally like to issue a call like this so that I integrate this w shell
> scripts:
>
>     xsltproc mytransform.xslt myfile.xml --param nodelist "alpha,beta"
>
> And get this back:
>
> <graph>
>     <node id="alpha"/>
>     <node id="beta"/>
>     <edge from="alpha" to="beta"/>
>     <edge from="beta" to="beta"/>
>     <mymetadata id="123"/>
> </graph>
>
> I have two questions:
>
> 1. What is the best way to create a pattern match that is parameterized
> based on the incoming nodelist? I'd like to flexible about delimeters
> (e.g. have both "alpha,beta" and "alpha   ,   beta" work). I've tried
> playing with tokenize from EXSLT but can't figure how to use the
> resulting tokens to implement the filtering in a single-pass.
>
> 2. Is there a way to implement this to also include the alpha-gamma edge
> and the gamma node, based on the partial edge match to "alpha"? I know
> how to do this w multiple passes (e.g. by marking the edges, then the
> nodes, then filtering) but was wondering if there was a nice one-pass
> functional approach I've missed.
>
> Thank you in advance for your time.
>
> Ramon
>
> _________________________________
>
> Ramon M. Felciano
> INGENUITY Systems, Inc.

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