slide 46

For Expressions Iterate Over Sequences

• Performs iteration over sequences
• Like XSLT <xsl:for-each> except inside an XPath expression
• Apply an expression to every item in a sequence
• Returns a sequence of the items returned by the mapped expression
• Can work across multiple sequences
• Both 1-to-1 mapping and 1-to-many mapping are possible

  for $n in child::name
    return concat($n/fname, ' ', $n/surname)

  for $id in distinct-values(//@idref)
    return count(key('elements-by-id',$id))

  for $d in (0 to 6)
    return (current-date() +
    ($d * xdt:dayTimeDuration('P1D')))