hyphenToEmDash

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema" exclude-result-prefixes="xs" version="2.0">
    
    <!-- This template will take hyphen in the unittitle EAD tag and, in cases where it is between a lower-case letter and an upper-case letter, replace it within an em-dash -->
    <!--  For example: <unittitle>Correspondence-Wax</unittitle> to  <unittitle>Correspondence—Wax</unittitle> -->
    <!-- Be sure to use an XSLT 2.0 engine   -->
    
    <xsl:template match="@*|node()">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()"/>
        </xsl:copy>
    </xsl:template>
    
    <xsl:template match="//unittitle/text()">
        
        <xsl:analyze-string select="." regex="[a-z]-[A-Z]">
            <xsl:matching-substring>
                <xsl:value-of select="translate(., '-', '—')"/>
            </xsl:matching-substring>
            <xsl:non-matching-substring>
                <xsl:value-of select="."/>
            </xsl:non-matching-substring>
        </xsl:analyze-string>
        
    </xsl:template>
    
</xsl:stylesheet>

This template will take hyphen in the unittitle EAD tag and, in cases where it is between a lower-case letter and an upper-case letter, replace it within an em-dash