XSL/XPath to generate a list of ancestors?

<Dataset name="root">
    <A name="a1">
        <A name="a2">
            <A name="a3" />
        </A>
    </A>
    <B name="b1">
        <B name="b2"/>
    </B>
</Dataset>

<fullName>a1</fullName>
<fullName>a1.a2</fullName>
<fullName>a1.a2.a3</fullName>

<fullName>b1</fullName>
<fullName>b1.b2</fullName>

    <xsl:template name="fullName">
        <fullName>
            <xsl:call-template name="fullNameWorker" />
        </fullName >
    </xsl:template>

    <xsl:template match="*" name="fullNameWorker" mode="fullName">
        <xsl:if test=".!=/">
            <xsl:apply-templates select=".." mode="fullName"/>
            <xsl:if test="..!=/">.</xsl:if>
            <xsl:value-of select="@name"/>
        </xsl:if>
    </xsl:template>

============================================================
Nathan Potter                 Oregon State University, COAS
ndp at coas.oregonstate.edu   104 Ocean. Admin. Bldg.
541 737 2293 voice            Corvallis, OR   97331-5503
541 737 2064 fax