Dear Bob,
In principle this can be done with an XSLT transformation, but you will have to specify how to determine which elements should be replaced, what you want "identical" to mean, what you wish to happen at the edges, etc. For example, what should happen with elements in either page that have no corresponding element in the other; or if one element to be replaced happens to contain another being replaced (is the second one ignored). Etc.
Because the answers to those questions will vary, I doubt there is any general-purpose utility out there to do this. Fortunately, the strength of the platform is such that it gives us the means to write our own.
Here is a transformation that will populate all *leaf* element nodes (i.e. those with no element children) with the contents of the element of the same name in the same position in a resource document, where "position" is simply counting from the front in document order, irrespective of ancestry. It also assumes that names will correspond without namespace prefixes being an issue.
Any contents of the nodes being replaced will be tossed even if there is no corresponding element in the resource document. (It's rough and untested.)
exclude-result-prefixes="xs"
version="2.0">
<xsl:param name="path">path/from/new/to/old.xml</xsl:param>
<xsl:variable name="resource" select="document($path,/)"/>
<xsl:template match="node() | @*">
<xsl:copy>
<xsl:apply-templates select="node() | @*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="*[empty(*)]">
<xsl:variable name="index">
<xsl:call-template name="make-index"/>
</xsl:variable>
<xsl:copy>
<xsl:apply-templates select="@*"/>
<xsl:copy-of select="key('element-by-index',$index,$resource)/node()"/>
</xsl:copy>
</xsl:template>
<xsl:key name="element-by-index" match="*">
<xsl:call-template name="make-index"/>
</xsl:key>
<xsl:template name="make-index">
<xsl:value-of select="name()"/>
<xsl:text>|</xsl:text>
<xsl:number level="any"/>
</xsl:template>
</xsl:stylesheet>
Once you had this or something like it working, you could set it up in oXygen with a scenario that would prompt you for the path to the resource document at runtime.
Cheers, Wendell
