RE: API for extension functions (was HTML forms with XSLT sl

> > - how to provide context information (this has been my main reservation
in
> > adopting xt's style of interface: it's fine for "pure" 
> functions but doesn't
> > extend easily to functions that use context, e.g. the 
> current node or the system id of the containing stylesheet node.
> 
> Why can't you extend it by defining an interface along the lines of:
> 
> interface XPathContext {
>   Node getCurrentNode();
>   String getStylesheetSystemId();
>   ...
> }
> 
> ?
> 
> Then if the first argument of the Java function is of type 
> XPathContext,
> the XSLT processor will automatically pass the Java function an
> additional argument of type XPathContext representing the current
> context.
> 
That's certainly one possibility. Another (the one I was planning) is to say
that if the class containing the extension function implements Contextual,
then the method setContext(XPathContext) will be called before the function
itself is called.

Of course there's also a question as to exactly what context information
should be made available. It doesn't seem a particularly good idea, for
example, to provide access to the variable bindings. This relates to the
question of defining what side-effects are permissible.

Mike


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