XSLT: Namespace From Prefix in XSL 1.0

When transforming XML Schema (XSD) files in XSLT 1.0, it quickly becomes necessary to resolve the namespace from the prefix of any given element or attribute.  Sometimes these elements and attributes are not stored as actual elements and attributes, which makes it necessary to resolve them in a different manner. For example, in the following XSD snippet, iso_639-3:LanguageCodeSimpleType is not a node, element nor is it an attribute, rather it is a text value of the type attribute.

<xsd:schema 
  xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
  xmlns:iso_639-3="http://niem.gov/niem/iso_639-3/2.0">
    <xsd:attribute name="languageCode" 
      type="iso_639-3:LanguageCodeSimpleType"/>
</xsd:schema>

One way to resolve what namespace the iso_639-3 prefix is associated with, is to extract the prefix from the text and use the following simple XSLT 1.0 function/template.

<xsl:template name="namespaceFromPrefix">
  <xsl:param name="sPrefix"/>
  <xsl:value-of select="/*/namespace::*[name() = $sPrefix]"/>
</xsl:template>

If one were to pass in the prefix iso_639-3 the return value would be http://niem.gov/niem/iso_639-3/2.0