Re: result documents in an XSLT step?

Thanks again, Martin. For the benefit of anyone reading the list archive in
the future with the same question in mind, see pp. 55–58 and 128–29 of
Erik's book. There he uses <p:with-option> for illustrative purposes, but
the difference is broader.

On Mon, Nov 2, 2020 at 1:57 PM Martin Honnen <martin.honnen@gmx.de> wrote:

> On 02.11.2020 18:41, David Birnbaum wrote:
>
> > For future reference, though, I'd be grateful for the opportunity to
> > confirm the source of my misunderstanding of how to use <p:filter> — not
> > only my failure to use a wrapper (I understand why that's important),
> > but why it requires curly braces inside single quotation marks inside
> > the double quotation marks around the value of the @select attribute. By
> > way of attempting my own explanation: The spec at
> > https://spec.xproc.org/master/head/steps/#c.filter says that @select on
> > <p:filter> is a string, and that "the select expression is computed
> > dynamically." Meanwhile, the other spec at
> > https://spec.xproc.org/master/head/xproc/#p.with-input says that @select
> > on <p:with-input> is an XPath expression. I think my mistake was
> > assuming (instead of checking the spec carefully) that the value
> > of @select would always and everywhere be an XPath expression, as (I
> > think) it is inside XSLT wherever it is part of the signature of an
> > element in the XSLT namespace. If it is a string, though, I need to
> > dereference the string value of $current-paradigm, put it in quotes, and
> > use that as one of the comparands inside the predicate, and the literal
> > single quotes become the quotes around the string value and the curly
> > braces inside them serve the usual AVT function of interpreting the
> > XPath expression in place.
>
> I will leave the explanation to the XProc guys but as for your
> description and the difficulties to understand the difference, I think,
> if you don't already have it, consider to get Erik Siegel's book on
> XProc 3 (XProc 3.0 Programmer Reference), he has a section explaining
> when XPath expressions are evaluated by the pipeline and when they are
> evaluated by the step itself.
>
> In general I think his book is very helpful to serve as an introduction
> to a user of XProc 3, better than the specs which by their nature are
> too formal and more geared towards implementors.
>
>
>
>