XSLT - Add new element at a specific location

I'm new to XSLT and I don't know how to accomplish the following.

Below is a part of a xbrl document, generate开发者_运维技巧d by another program. Via XSLT, I would like to add an extra element at the position of my comment line:

<xbrli:context id="ctx1">
[...]
</xbrli:context>
//Insert a new element here!
<bd-ob-tuple:TaxData>
[...]
</bd-ob-tuple:TaxData>

At that location, I would like to add the following element using XSLT:

<xbrli:unit id="EUR">
  <xbrli:measure>iso4217:EUR</xbrli:measure>
</xbrli:unit>

So that the final result will be:

<xbrli:context id="ctx1">
[...]
</xbrli:context>
<xbrli:unit id="EUR">
  <xbrli:measure>iso4217:EUR</xbrli:measure>
</xbrli:unit>
<bd-ob-tuple:TaxData>
[...]
</bd-ob-tuple:TaxData>

(The xbrli:context element has only one occurence in the whole document, so that perhaps makes it easier to locate the mentioned position for the new element?)

Is there a way I can accomplish this via XSLT?

---

This transformation:

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
 xmlns:xbrli="some:xbrli" exclude-result-prefixes="xbrli">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>

 <xsl:template match="node()|@*" name="identity">
  <xsl:copy>
   <xsl:apply-templates select="node()|@*"/>
  </xsl:copy>
 </xsl:template>

 <xsl:template match="xbrli:context">
  <xsl:call-template name="identity"/>
  <xbrli:unit id="EUR">
     <xbrli:measure>iso4217:EUR
     </xbrli:measure>
  </xbrli:unit>
 </xsl:template>
</xsl:stylesheet>

when applied on the following XML document (cleaning and wrapping the provided text to make it well-formed):

<t xmlns:xbrli="some:xbrli" xmlns:bd-ob-tuple="some:bd-ob-tuple">
    <xbrli:context id="ctx1"> [...] </xbrli:context>
    <bd-ob-tuple:TaxData> [...] </bd-ob-tuple:TaxData>
</t>

produces the wanted, correct result:

<t xmlns:bd-ob-tuple="some:bd-ob-tuple" xmlns:xbrli="some:xbrli">
    <xbrli:context id="ctx1"> [...] </xbrli:context>
    <xbrli:unit id="EUR">
        <xbrli:measure>iso4217:EUR
     </xbrli:measure>
    </xbrli:unit>
    <bd-ob-tuple:TaxData> [...] </bd-ob-tuple:TaxData>
</t>

Explanation: Use of the identity rule, overriden for xbrli:context .

---

How about this:

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:msxsl="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="msxsl"
    xmlns:xbrli="http://xbrli" xmlns:bd-ob-tuple="http://bd-ob-tuple" >
    <xsl:output method="xml" indent="yes"/>
    <xsl:template match="@* | node()">
        <xsl:copy>
            <xsl:apply-templates select="@* | node()" />
        </xsl:copy>
        <xsl:if
            test="local-name() = 'context' and namespace-uri() = 'http://xbrli'">
            <xbrli:unit id="EUR">
                <xbrli:measure>iso4217:EUR</xbrli:measure>
            </xbrli:unit>
        </xsl:if>
    </xsl:template>
</xsl:stylesheet>