Re: result of A&Q at XML Prague preconf day

Hi all,

Nice to see some of you at XML Prague. And really glad about Norman Walsh
presentation about Xproc V2.
In my company we are converting all our "perl/xslt/pieces of xproc" dev to
fully Xproc pipeline. It was a bit painfull but we are on the good way and
we are really happy with it.

http://www.w3.org/TR/xproc-v2-req/ matches exactly our wishes (especialy
parameters and XDM values), but let's add a few ones if this is not too
late :

1) p:import
It would be IMHO really, really nice to have an import mechanism in xproc
just like XSLT.
That would allow to override some step just like we often do in xslt
(priority, precedence is so powerfull !)

2) Accessing serialization method (especialy for p:xslt)
One of the biggest limitation we had is to used our huge amount of XSLT
without refactoring them all.
XDM parameters in Xproc V2 should solve the problem of typed xslt
parameters that we use a lot.
The other part of the problem is about serialization : Xproc says "this is
my job, not xslt's ones". That's sound ok but how to deal with
character-maps in Xproc for instance (we use this a lot for epub
compatibility)?
What about xsl:result-document, ok we can access them from the secondary
output but how to serialize them properly (according to the named
xsl:output in the xslt) ?
We have made our own xslt step which is a kind of "hack" of p:xslt. (see
http://lists.w3.org/Archives/Public/xproc-dev/2014Feb/0012.html)

For the moment the only information accessible within the secondary output
is p:base-uri() which here comes from the "xsl:result-document/@href".
In Xproc V2 it would be nice IMHO to access the serialisation options
something like "p:serialization-method()", "p:serialization-indent()", etc.
?

3) Conditionnal options (kind of @use-when)

Let's say I have "calculate" an option and I want to send it to a step ONLY
IF it's not empty ? that means more generaly using the default option if
the one I have calculate don't satisfies a condition. It seems I have to
use p:choose for this.

For example :
<p:variable name="my_indent" select="...complex xpath..."/>
<p:choose>
   <p:when test="indent!=''">
     <p:store href="foo.xml">
        <p:with-option namet="indent" select="$my_indent"/>
     </p:store>
   </p:when>
   <p:otherwise>
     <p:store href="foo.xml"/>
   </p:otherwise>
</p:choose>

If I have 10 options, then I have to make all the combination which become
a nightmare...

In Xproc V2 it would be nice IMHO to have a way to say if an option must be
send or not (i.e. default behaviour) :
For example :

<p:store href="foo.xml">
        <p:with-option namet="indent" select="$my_indent"
use-if="$my_indent!=''"/>
</p:store>

or maybe more generaly having a "p:if" :

<p:store href="foo.xml">
     <p:if test="$my_indent!=''">
        <p:with-option namet="indent" select="$my_indent"/>
    </p:if>
</p:store>

(just like i would conditionnaly add an attribute to a element in xslt :
<div>
<xsl:if test="$class!=''">
   <xsl:attribute name="class" select="$class"/>
</xsl:if>
</div>
)

4) cx:eval
We have found very usefull to use cx:eval in our process. Actually we use
an XML "profile" file to drive our xproc pipeline. This file let the user
change parameters easily.
But we consider adding an xslt to an xml2epub transformation should appear
in this file because it's a kind of "parameter".
This is how it look :
<mode name="xml2extract.xml">
 <parameters>
<param name="percent" value="9"/>
</parameters>
 <steps>
<igs:xslt xml:base="http://localhost:777/neodev.trunk/EPUB_RES/">
 <p:with-option xmlns:p="http://www.w3.org/ns/xproc"
name="store_main_result_at" select="$extract.uri"/>
 <p:input xmlns:p="http://www.w3.org/ns/xproc" port="stylesheet">
<p:document href="xsl/common/modules/extract/extract_dtd_igs_v2.5.xsl"/>
 </p:input>
</igs:xslt>
</steps>
</mode>

After a bit workaround, that's really great, dynamic evaluation work fine :)

But we have made assumptions on imported xpl file of the evaluated pipeline.

For Xproc V2,  it would be nice IMHO :
- to have a "p:eval" (just like xsl:evaluate in xslt3)
- that the evaluation can be done in the context of the current xproc :
that means not be "oblige" to construct a whole pipeline to evaluation

4) syntax : variable / groups

Last requirement is about p:variable which can't be place anywhere (even
with a p:pipe within the variable which make it independant)
We have often add p:group so we can declare a variable but p:group has also
"side effects"...
I guess there is reason for this but well we have the feeeling this is a
bit verbose, not to say tedious ;)

Hope this helps

Regards

Matthieu






2014-02-14 16:34 GMT+01:00 Geert J. <geert.josten@dayon.nl>:

> Wish I were in Prague now.. alas..
>
>
>
> Added my 2c on Twitter..
>
>
>
> Have fun!
>
>
>
> *Van:* James Fuller [mailto:james.fuller.2007@gmail.com]
> *Verzonden:* vrijdag 14 februari 2014 12:43
> *Aan:* xproc-dev@w3.org
> *Onderwerp:* result of A&Q at XML Prague preconf day
>
>
>
> Thank you to everyone who attended ... the survey of opinion was
> lightweight, but a useful quick sample ... to summarise;
>
>
>
> Is XProc v2 requirements doc on the right track ?
>
> * IMHO, not enough ppl have read the requirements doc to begin answering
> the question reasonably
>
> * propose that folks take another look at
> http://www.w3.org/TR/xproc-v2-req/
>
>
>
> How XProc is being used
>
> * most ppl using XProc to replace 'duct tape' solutions.
>
> * many using it as basis for publishing
>
>
>
> Which user is most important in XProc solution
>
> * the developer implementing the solution was by far the most important
> user in the toolchain currently
>
>
>
> XProc
>
> * Parameters still a burning topic, looks unlikely that we could drop for
> v2
>
>
>
> Use Cases
>
> * JF to sit with Romain Deltour
>
> * JF to sit with Gerrit Imsieke
>
>
>
> Was suggested that DITA / XProc should be promoted
>
> * Jim Fuller will setup XProc meetup at DITA Europe (maybe George from
> oXygenXML can provide some advice)
>
> * XProc submissions for DITA orientated conferences
>
> * expect another mail to the list on this one following up
>
>
>
> Over XML Prague (and as ever via mailing list) Please feel free to
> approach any of us on the Working Group
>
>
>
> * Norm Walsh
>
> * Alex Milowski
>
> * Mohamed Zergaoui
>
> * Jim Fuller
>
>
>
> And give us your opinions, criticisms and what is important to you for
> XProc v2.
>
>
>
> thx, Jim Fuller
>



-- 
Matthieu Ricaud-Dussarget
IGS-CP - Développeur XML
05 45 37 09 49