What value is used exactly for the <role> element ?
Relator terms or relator codes ?

The MARC21slim2MODS stylesheet use both MARC subfield e (term) and subfield
4 (code).

May be it's a good practice to use only one value (the term for example) ?

or may be both like this :
<role code="ill">Illustrator</code>
but also :
<role code="ill"/>
But for internationalisation purpose, why not do this :

<role code="ill" xml:lang="fre">Illustrateur</code>
<role code="ill" xml:lang="eng">Illustrator</code>

For UNIMARC2MODS.xsl, i use a "lookup table" to convert UNIMARC relator
codes to MARC21 relator terms :

the lookup "table" : relators.xml
----<?xml version="1.0" encoding="UTF-16"?><!--    2002 Yves Pratter
<[log in to unmask]>
    Sources :        MARC 21 Concise Format for BIBLIOGRAPHIC DATA : 2002
Concise Edition
        UNIMARC Manual : Bibliographic Format 1994
    Notes :        uid : UNIMARC code        mid : MARC21  code
Relator value is the MARC21 relator--><relators>    <relator uid='005'
mid='act'>Actor</relator>    <relator uid='010' mid='adp'>Adapter</relator>
<relator uid='020' mid='ann'>Annotator</relator>
    ...    <relator           mid='wdc'>Woodcutter</relator>    <relator
uid='760' mid='wde'>Wood-engraver</relator>    <relator uid='770'
mid='wam'>Writer of accompanying
The xslt code to convert the unimarc relators :

 <xsl:template name="role">  <xsl:choose>   <xsl:when
test="marc:subfield[@code='e']">    <role><xsl:value-of
select="marc:subfield[@code='e']"/></role>   </xsl:when>   <xsl:when
test="marc:subfield[@code='4']">        <!-- load the lookup table in
variable $relators -->    <xsl:variable name="relators"
select="document('relators.xml')"/>        <xsl:for-each
select="marc:subfield[@code='4']">         <!-- UNIMARC relator code to
convert -->     <xsl:variable name="code" select="text()"/>     <role>
<!-- get MARC21 relator term -->      <xsl:value-of
select="$relators//relator[@uid=$code]"/>     </role>    </xsl:for-each>
<role><xsl:value-of select="text()"/></role>    </xsl:for-each>
</xsl:when>  </xsl:choose> </xsl:template>
Of course it's possible to use this code in MARC21slim2MODS.xsl to convert
subfield $4 (MARC21 relator code) to MARC21 relator term.
Just select relator element with attribute mid :
<xsl:value-of select="$relators//relator[@mid=$code]"/>
What is your opinion ?