1.1 The Module

This module defines a way of associating a DOM fragment to a node and a way of accessing the fragment. The use case is that an author can store information which isn't directly dependent to the instance data but is required for creating a user interface. An example could be an instance representing a mail box and the author want to store a valid from the UI whether a mail was selected. This selected state would then be defined in the template.

The module name to be used for this extension is defined as exf:template

1.2 The exf:template Attribute

The exf:template must be placed on a xforms:bind element and it must be a [XPath 1.0] expression selecting a node-set. The first node in document order from this node-set is used to create the template. The assignment of templates to instance nodes happens during the rebuild processing in the following way:

1. Every node from the xforms:bind element's context is selected for template assignment

2. If a selected node hasn't got a template then the exf:template is evaluated to locate its template. If the template evaluates to a non-empty node-set then the first node in document order from the node-set is cloned and assigned to the instance node as its template.

<xforms:model>
  <xforms:instance id="default">
    <emailbox xmlns="">
      <email from="contact@exforms.org" subject="How to..."/>
      <email from="spam@spammer.com" subject="Buy this for free"/>
  </xforms:instance>
  <xforms:instance id="template">
    <template xmlns="">
      <selected>false</selected>
    </template>
  </xforms:instance>
  <xforms:bind nodeset="email" exf:template="instance('template')"/>
</xforms:model>

1.3 The exf:template() Function

node-set exf:template(node-set?)

The exf:template-owner returns the template owner for the current context node. If the context node is in a template then the function returns the empty node-set.

<xforms:repeat nodeset="email">
  <xforms:input ref="exf:template()/selected">
    <xforms:label>Selected?</xforms:label>
    <xforms:setvalue ref="ext:template-owner()" value="true" ev:event="click"/>
  </xforms:input>
</xforms:repeat>

1.4 The exf:template-owner() Function

node-set exf:template-owner()

The exf:template-owner returns the template owner for the current context node. If the context node is in a template then the function returns the empty node-set.

<xforms:repeat nodeset="email">
  <xforms:input ref="exf:template()/selected">
    <xforms:label>Selected?</xforms:label>
    <xforms:setvalue ref="ext:template-owner()" value="true" ev:event="click"/>
  </xforms:input>
</xforms:repeat>

1.5 The exf:template-assign Action

This action (re-)associates or removes a template.

Common Attributes: Must have a single-node binding (defined in XForms).

Attributes:

Special Attributes:

template

Optional [XPath 1.0] node-set expression to select the node to use for the template.

The processing for exf:template-assign is as follows:

1. The single-node binding is evaluated to determine which node should be processed

2. If the attribute template is omitted then the node's associated template is dropped. If the node has no template this action has no effect.

   otherwise

   template is evaluated and if it selects a node-set then the first node in document order from that node-set is cloned and associated as a template. If the node-set was empty then any associated template is removed. If the evaluation produced anything but a node-set then this action has no effect.

<xforms:trigger>
  <xforms:label>Make additional selected for the first &lt;email> in template</xforms:label>
  <xforms:action ev:event="DOMActivate">
    <xforms:insert nodeset="instance('template')/selected" at="1" position="after"/>
    <exf:template-assign ref="email" template="instance('template')"/>
  </xforms:action>
</xforms:trigger>

2.1 Normative References

XForms 1.0

XForms - Version 1.0, John M. Boyer, David Landwehr, Roland Merrick, T. V. Raman, Micah Dubinko, Leigh L. Klotz, Jr., 2006. W3C Recommendation available at: http://www.w3.org/TR/xforms/.

XML Events

XML Events - An events syntax for XML, Steven Pemberton, T. V. Raman, Shane P. McCarron, 2002. W3C Recommendation available at: http://www.w3.org/TR/xml-events/.

XPath 1.0

XML Path Language (XPath) Version 1.0, James Clark, Steve DeRose, 1999. W3C Recommendation available at: http://www.w3.org/TR/xpath.

XML Schema part 1

XML Schema Part 1: Structures, Henry S. Thompson, David Beech, Murray Maloney, Noah Mendelsohn, 2001. W3C Recommendation available at: http://www.w3.org/TR/xmlschema-1/.

XML Schema part 2

XML Schema Part 2: Datatypes, Paul V. Biron, Ashok Malhotra, 2001. W3C Recommendation available at: http://www.w3.org/TR/xmlschema-2/.

RFC 2119

RFC 2119: Key words for use in RFCs to Indicate Requirement Levels, S. Bradner, 1997. Available at http://www.ietf.org/rfc/rfc2119.txt.