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Re: Binding : Do I need a nodeset?

From: Adam Flinton <adam.flinton@nhs.net>
Date: Thu, 6 Aug 2009 14:23:10 +0100
Message-ID: <4A7AD93E.1070200@nhs.net>
To: Mark Birbeck <mark.birbeck@webbackplane.com>
CC: "www-forms@w3.org" <www-forms@w3.org>
Mark Birbeck wrote:
> Hi Adam,
>
> You always need a nodeset, even with @calculate. I'm surprised that
> you are getting Chiba to output something using @calculate with no
> @nodeset value, so you might want to double-check that you really are
> seeing what you think you are seeing.
>
> One way to understand xf:bind is to see it as adding extra
> 'properties' to an instance node. I realise that in your particular
> example you want to have relevance based only on the result of an
> expression, but that's not possible; in XForms you have to make some
> existing node relevant, based on the expression you want. And if no
> obvious node exists, then unfortunately, as you have discovered, you
> usually need to invent one.
>

That is what I was thinking.....

I wonder if there is scope within any improvements to XForms to have a
<xforms:variable/> element

Much as with XSLT or similar......

The normal use cases are wrt checking values e.g. my "check unique" check:

        <xforms:bind
            calculate="if(instance('OIDVals')/oids/@active = 1,true(),if
(count(instance('OIDVals')//ov[@full = instance('main')/@full]) &lt;=
instance('OIDVals')//oids[1]/@exist,true(),false()))"
            id="unique_OID" nodeset="instance('uniqueOID')/@val"/>

Or as stated in the previous post wrt displaying one group vs another.

Adam

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Received on Thursday, 6 August 2009 13:24:34 GMT

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