Use case for fn:for-each-pair

for-each-pair.xq

(: See http://stackoverflow.com/questions/17975306/aligning-fields-based-on-position-using-xslt :)

(: XML input :)

(:
<?xml version="1.0" encoding="UTF-8"?>
<collections>
    <collection name="anyCollection">
        <record>
            <field name="materia">comida; bebida; fiesta</field>
            <field name="subject">food; drink; party</field>
            <field name="recordid">abc0001</field>
        </record>
        <record>
            <field name="materia">comida; bebida; fiesta</field>
            <field name="subject">food; drink; party</field>
            <field name="recordid">abc0002</field>
        </record>
        <record>
            <field name="materia">bebida; fiesta</field>
            <field name="subject">food; drink; party</field>
            <field name="recordid">abc0003</field>
        </record>
        <record>
            <field name="materia">fiesta; sombreros; música; baile; agua; cerveza; sopa</field>
            <field name="subject">party; hats; music; dance; water; beer; soup</field>
            <field name="recordid">abc0004</field>
        </record>
        <record>
            <field name="materia">comida; bebida; fiesta; sombreros; música</field>
            <field name="subject">food; drink; party; hats; music</field>
            <field name="recordid">abc0005</field>
        </record>
        <record>
            <field name="materia">comida; bebida; cerveza; agua</field>
            <field name="subject">food; drink; beer; water</field>            
            <field name="recordid">abc0006</field>
        </record>        
        <record>
            <field name="materia">fiesta; sombreros; música; baile; agua; cerveza</field>
            <field name="subject">party; hats; music; dance; water; beer</field>
            <field name="recordid">abc0007</field>
        </record>       
    </collection>
</collections>
:)

(: XQuery :)

for $record in //record
for $spa in $record/field[@name='materia']
for $eng in $record/field[@name='subject']
for $id in $record/field[@name='recordid']/text()
for $pair in for-each-pair(
    tokenize($spa, '; '), 
    tokenize($eng, '; '),
    function($x, $y) { $x || '_' || $y || '&#xa;' })
group by $pair
order by $pair
return (
    for $p in $pair
    return
        concat('&#xa;',$p),
    for $i in $id
    return
        concat($i,'&#xa;')
)