[xsl] Best way to represent an item and its context?

["Costello, Roger L." <costello@xxxxxxxxx>]

Hi Folks,

Consider this XML document:

<?xml version="1.0"?>
<Book>
      <title>GML</title>
      <author>Ron Lake</author>
      <date>2004</date>
</Book>

Suppose that while processing that XML document I get to the author element:

      <author>Ron Lake</author>

I want to store this element and its context in a variable. The context of
author is the entire document.

So I want a function that takes as input the author element and the Book
element and returns a representation of the element and its context:

item-in-context :: Item -> Context -> Item-in-Context

Read as: "The function item-in-context has two arguments -- an item (element)
and a context -- and it returns a representation of the element and its
context."

Here I invoke that function and store the result into a variable:

<xsl:template match="/">

      <xsl:variable name="v1" select="f:item-in-context(Book/author, Book)"
/>

</xsl:template>

I have various functions which operate on that Item-in-Context variable. For
example, one function returns the item's parent:

parent :: Item-in-Context -> Item

Here I invoke the parent function and store the result into a second
variable:

<xsl:template match="/">

      <xsl:variable name="v1" select="f:item-in-context(Book/author, Book)"
/>

      <xsl:variable name="v2" select="f:parent($v1)" />

</xsl:template>

What's the best way to represent an item and its context?

/Roger