Template parameters can be written as $param (i.e. an identifier prefixed by a dollar character), or as ${param} (i.e. additional braces). There is also the variant ${param/enc} containing an additional output encoding. All these parameters must be imported into the current template or page definition by from-caller or from-context attributes, see the elements ui:template and ui:page. For an overview how template parameters work see the chapter about Templates.

The parameters $int and $ext play a special role in the context of iterations. They need not to be imported into the current context, as they are automatically set for every iteration. See the elements ui:iterate and ui:enumerate for details.