Changes

* The [[XQuery 3.0#Simple Map Operator|Simple Map Operator]] can be used to trigger an action if a value has a single item. The following two expressions are equivalent:

let $s := "X" return (

(: OLD :) if(count($s) = 1) then 'OK' else (),

* If you want to choose the first non-empty item from two arguments, we can use the position predicate:

let $s := "X" return (

(: OLD :) if(exists($s)) then $s else 'default',

== Computed Elements ==

Returns dynamically named elements:

let $root := "element"

let $value := "hi"

This snippet transform a ''flat'' list of elements with <code>parentId</code>-references to a nested list.

declare function local:link($entries as node()*, $id as xs:string) {

let $entry := $entries[@id eq $id],

This snippet converts an IP address to its numeric representation:

let $ip := '134.34.226.65'

return fold-left(

This snippets returns the number of JPG files in a directory and its subdirectories:

basex "count(file:list('.',true(),'*.jpg'))"</syntaxhighlight>