XQuery 4.0

This article is part of the XQuery Portal. It provides a summary of the most important features of the XPath and XQuery Functions and Operators 4.0 W3C Editor's Draft.

Otherwise operator

$a otherwise $b

… is equivalent to …

if(exists($a)) then $a else $b

Braced if, optional else

if($a) { $b } else { $c }

if($a) { if($b) { $c } }

Arrow map operator

"The cat sat on the mat" => tokenize() =!> concat(".") =!> upper-case() => string-join(" ")

Numeric literals

1_048_576

0xFC00

0b111000

Abbreviated function syntax

let $inc := fn($n) { $n + 1 } return $inc(99)

… is equivalent to …

let $inc := function($n) { $n + 1 } return $inc(99)

Focus functions (arity-one)

let $inc := fn { . + 1 } return $inc(99)

fn:filter($integers, fn { . > 5 })

fn:iterate-while($number, fn { . < 100 }, fn { . * . })

Optional arguments

declare function strings:get( $value, $default := "EMPTY" ) { $value otherwise $default } strings:get('john')

Keyword arguments

declare function coordinates( $x := 0, $y := 0 ) { map { "x" : $x, "y" : $y } } coordinates(y := 123)

String templates

`Name: { $name }, { $age }`

… is equivalent to …

"Name: " || $name || ", " || $age

… or …

``[Name: `{ $name }`, `{ $age }`]``

Union node tests

/xml/child::(a|b)

/xml/element::(c|d)

Compact lookup syntax

$address?$name, $city?"city code"

… is equivalent to …

$address?($name), $city?("city code")

Maps

20 new map functions have been added in XPath and XQuery Functions and Operators 4.0, namely

• fn:atomic-equal
• map:build
• map:contains
• map:entries
• map:entry
• map:filter
• map:find
• map:for-each
• map:get
• map:keys
• map:merge
• map:of-pairs
• map:pair
• map:pairs
• map:put
• map:remove
• map:replace
• map:size
• map:substitute
• map:values

Map functions are described in Map Module.

Arrays

30 new array functions have been added in XPath and XQuery Functions and Operators 4.0, namely

• array:append
• array:build
• array:empty
• array:exists
• array:filter
• array:flatten
• array:fold-left
• array:fold-right
• array:foot
• array:for-each
• array:for-each-pair
• array:get
• array:head
• array:index-where
• array:insert-before
• array:join
• array:members
• array:of-members
• array:put
• array:remove
• array:replace
• array:reverse
• array:size
• array:slice
• array:sort
• array:split
• array:subarray
• array:tail
• array:trunk
• array:values

Array functions are described in Array Module.

Changelog

Version 11.0

• Added otherwise operator