Question on xpath syntax

I cannot seem to use the value of "." or self::node() as it were.

I want to do the simple update value when the drop-down changes, using
the value in the select in an xpath statement to another instance.
I hope I can demonstrate without all the code, but happy to submit it.

<xforms:group ref="instance('sensor-change')">

  <xforms:select1 ref="station" id="station" appearance="minimal">
    <xforms:item>
    ......
    </xforms:item>
    <!-- what's wrong with this? -->
    <xforms:setvalue ref="../lat" value="instance('sites')/site[sta=.]/lat" />
  </xforms:select1>

  <xforms:input ref="lat" id="lat" />

</xforms:group>

it did not work, but specify the entire xpath and voilà :

<xforms:setvalue ref="../lat" value="instance('sites')/site[sta=instance('sensor-change')/station]/lat" />

What is happening here? is the ref "lost" when an instance is declared?

Thank you.  RTFM would be a welcomed response, just tell
me which M.

--Hank

Hank Ratzesberger
Institute for Crustal Studies
University of California, Santa Barbara
805.893.8042
805.893.8649 (fax)





--
You receive this message as a subscriber of the [hidden email] mailing list.
To unsubscribe: mailto:[hidden email]
For general help: mailto:[hidden email]?subject=help
ObjectWeb mailing lists service home page: http://www.objectweb.org/wws

On Wed, Jan 24, 2007 at 04:12:31PM -0800, Hank Ratzesberger wrote:
> <xforms:group ref="instance('sensor-change')">

This sets the default instance for all controls in the group.

>    <!-- what's wrong with this? -->
>    <xforms:setvalue ref="../lat" value="instance('sites')/site[sta=.]/lat"
>    />

Looks for instance('sensor-change')/../lat, which doesn't exist and so
is empty.

Side note: I'd really like to see errors when you pick something that
doesn't exist.  Is there a switch?

> <xforms:setvalue ref="../lat"
> value="instance('sites')/site[sta=instance('sensor-change')/station]/lat" />

Now you're looking in the right instance.


--



--
You receive this message as a subscriber of the [hidden email] mailing list.
To unsubscribe: mailto:[hidden email]
For general help: mailto:[hidden email]?subject=help
ObjectWeb mailing lists service home page: http://www.objectweb.org/wws

Hank Ratzesberger wrote:

  Hi

>     <xforms:setvalue ref="../lat"
> value="instance('sites')/site[sta=.]/lat" />
>   </xforms:select1>

  In XPath, the context item (the current node) in a predicate is the
node whose the predicate is a predicate of.  So in "site[sta=.]", the
"." refers to "site".  More generaly, the context item changes in
several places in the XPath expression.

  What you want is the context item as it is at the beginning of the
expression.  This is dependent of the host language (here XHTML).  XSLT
for example provides the current() function.  I think XHTML 1.1
provides this same current() function, but XHTML 1.0 doesn't.

  Finally, I thought Orbeon Forms supported this function, but
http://www.orbeon.com/ops/doc/home-changes-35#d33e416 seems to say it
doesn't.

  Orbeon guys will have to confirm for the Orbeon Forms part.

  Regards,

--drkm






















       

       
               
___________________________________________________________________________
Découvrez une nouvelle façon d'obtenir des réponses à toutes vos questions !
Profitez des connaissances, des opinions et des expériences des internautes sur Yahoo! Questions/Réponses
http://fr.answers.yahoo.com



--
You receive this message as a subscriber of the [hidden email] mailing list.
To unsubscribe: mailto:[hidden email]
For general help: mailto:[hidden email]?subject=help
ObjectWeb mailing lists service home page: http://www.objectweb.org/wws

On Wed, Jan 24, 2007 at 04:22:28PM -0800, Mike Leary wrote:
> value="instance('sites')/site[sta=.]/lat"

> value="instance('sites')/site[sta=instance('sensor-change')/station]/lat" />

Oops, I answered an unasked question. :)  This *might* work unless
instance is heavy-footed:

> value="instance('sites')/site[sta=station]/lat" />

I think the "../lat"s could just be "lat", as in the <input>, since
you're starting at the root node.


--



--
You receive this message as a subscriber of the [hidden email] mailing list.
To unsubscribe: mailto:[hidden email]
For general help: mailto:[hidden email]?subject=help
ObjectWeb mailing lists service home page: http://www.objectweb.org/wws

Mike Leary wrote: No, there isn't. At best it would be an optional warning: it is
perfectly legal to have bindings to non-existent nodes. But granted it
would be very useful.

-Erik

--
Orbeon Forms - Web Forms for the Enterprise Done the Right Way
http://www.orbeon.com/



--
You receive this message as a subscriber of the [hidden email] mailing list.
To unsubscribe: mailto:[hidden email]
For general help: mailto:[hidden email]?subject=help
ObjectWeb mailing lists service home page: http://www.objectweb.org/wws

Thanks for everyone's insights.

It seems verbose, but works:

<xforms:setvalue ref="../lat" value="instance('sites')/site[sta=instance('sensor-change')/station]/lat" />
<xforms:setvalue ref="../lon" value="instance('sites')/site[sta=instance('sensor-change')/station]/lon" />
 
> I think the "../lat"s could just be "lat", as in the <input>, since
> you're starting at the root node.

What I noticed is that within xforms elements that have a ref= attribute,
the axis step changes to the ref, so ../ is necessary.

<xforms:group ref="instance('sensor-change')">
  <xforms:select1 ref="station">
    ...
    <xforms:setvalue ref="../lat" ......
  </xforms:select1>
  <xforms:input ref="lat" id="lat" />
</xforms:group>

--Hank





--
You receive this message as a subscriber of the [hidden email] mailing list.
To unsubscribe: mailto:[hidden email]
For general help: mailto:[hidden email]?subject=help
ObjectWeb mailing lists service home page: http://www.objectweb.org/wws

I think you also need an ev:event="xforms-value-changed" on your
setvalue, and probably an action around them if you use two...

Leigh.

Hank Ratzesberger wrote:

--
You receive this message as a subscriber of the [hidden email] mailing list.
To unsubscribe: mailto:[hidden email]
For general help: mailto:[hidden email]?subject=help
ObjectWeb mailing lists service home page: http://www.objectweb.org/wws