XQuery, XPath, and XSLT Functions and Operators Namespace Document

2 XQuery and XPath Functions

This section lists all of the functions defined in the [XPath and XQuery Functions and Operators 3.1] specification. Each function and operator is uniquely identified with a URI of the form: “http://www.w3.org/2005/xpath-functions#name” where name is the name of a function or operator, such as “max”: http://www.w3.org/2005/xpath-functions#max.

The normative definitions of these functions are in the [XPath and XQuery Functions and Operators 3.1] specification. For convenience, a very brief, non-normative summary of each function is provided. For details, follow the link on the “Summary:” introductory text below each function.

QName

QName(xs:string?, xs:string) as xs:QName

Returns an xs:QName value formed using a supplied namespace URI and lexical QName.

available-environment-variables

available-environment-variables() as xs:string*

Returns a list of environment variable names that are suitable for passing to fn:environment-variable, as a (possibly empty) sequence of strings.

avg

avg(xs:anyAtomicType*) as xs:anyAtomicType?

Returns the average of the values in the input sequence $arg, that is, the sum of the values divided by the number of values.

collection

collection() as item()*

collection(xs:string?) as item()*

Returns a sequence of items identified by a collection URI; or a default collection if no URI is supplied.

count

count(item()*) as xs:integer

Returns the number of items in a sequence.

current-date

current-date() as xs:date

Returns the current date.

current-dateTime

current-dateTime() as xs:dateTimeStamp

Returns the current date and time (with timezone).

current-time

current-time() as xs:time

Returns the current time.

deep-equal

deep-equal(item()*, item()*) as xs:boolean

deep-equal(item()*, item()*, xs:string) as xs:boolean

This function assesses whether two sequences are deep-equal to each other. To be deep-equal, they must contain items that are pairwise deep-equal; and for two items to be deep-equal, they must either be atomic values that compare equal, or nodes of the same kind, with the same name, whose children are deep-equal, or maps with matching entries, or arrays with matching members.

default-collation

default-collation() as xs:string

Returns the value of the default collation property from the static context.

default-language

default-language() as xs:language

Returns the value of the default language property from the dynamic context.

distinct-values

distinct-values(xs:anyAtomicType*) as xs:anyAtomicType*

distinct-values(xs:anyAtomicType*, xs:string) as xs:anyAtomicType*

Returns the values that appear in a sequence, with duplicates eliminated.

doc

doc(xs:string?) as document-node()?

Retrieves a document using a URI supplied as an xs:string, and returns the corresponding document node.

doc-available

doc-available(xs:string?) as xs:boolean

The function returns true if and only if the function call fn:doc($uri) would return a document node.

element-with-id

element-with-id(xs:string*) as element()*

element-with-id(xs:string*, node()) as element()*

Returns the sequence of element nodes that have an ID value matching the value of one or more of the IDREF values supplied in $arg.

empty

empty(item()*) as xs:boolean

Returns true if the argument is the empty sequence.

environment-variable

environment-variable(xs:string) as xs:string?

Returns the value of a system environment variable, if it exists.

exactly-one

exactly-one(item()*) as item()

Returns $arg if it contains exactly one item. Otherwise, raises an error.

exists

exists(item()*) as xs:boolean

Returns true if the argument is a non-empty sequence.

filter

filter(item()*, function(item()) as xs:boolean) as item()*

Returns those items from the sequence $seq for which the supplied function $f returns true.

fold-left

fold-left(item()*, item()*, function(item()*, item()) as item()*) as item()*

Processes the supplied sequence from left to right, applying the supplied function repeatedly to each item in turn, together with an accumulated result value.

fold-right

fold-right(item()*, item()*, function(item(), item()*) as item()*) as item()*

Processes the supplied sequence from right to left, applying the supplied function repeatedly to each item in turn, together with an accumulated result value.

for-each

for-each(item()*, function(item()) as item()*) as item()*

Applies the function item $f to every item from the sequence $seq in turn, returning the concatenation of the resulting sequences in order.

for-each-pair

for-each-pair(item()*, item()*, function(item(), item()) as item()*) as item()*

Applies the function item $f to successive pairs of items taken one from $seq1 and one from $seq2, returning the concatenation of the resulting sequences in order.

format-date

format-date(xs:date?, xs:string) as xs:string?

format-date(xs:date?, xs:string, xs:string?, xs:string?, xs:string?) as xs:string?

Returns a string containing an xs:date value formatted for display.

format-dateTime

format-dateTime(xs:dateTime?, xs:string) as xs:string?

format-dateTime(xs:dateTime?, xs:string, xs:string?, xs:string?, xs:string?) as xs:string?

Returns a string containing an xs:dateTime value formatted for display.

format-time

format-time(xs:time?, xs:string) as xs:string?

format-time(xs:time?, xs:string, xs:string?, xs:string?, xs:string?) as xs:string?

Returns a string containing an xs:time value formatted for display.

function-arity

function-arity(function(*)) as xs:integer

Returns the arity of the function identified by a function item.

function-lookup

function-lookup(xs:QName, xs:integer) as function(*)?

Returns the function having a given name and arity, if there is one.

function-name

function-name(function(*)) as xs:QName?

Returns the name of the function identified by a function item.

generate-id

generate-id() as xs:string

generate-id(node()?) as xs:string

This function returns a string that uniquely identifies a given node.

has-children

has-children() as xs:boolean

has-children(node()?) as xs:boolean

Returns true if the supplied node has one or more child nodes (of any kind).

head

head(item()*) as item()?

Returns the first item in a sequence.

id

id(xs:string*) as element()*

id(xs:string*, node()) as element()*

Returns the sequence of element nodes that have an ID value matching the value of one or more of the IDREF values supplied in $arg.

idref

idref(xs:string*) as node()*

idref(xs:string*, node()) as node()*

Returns the sequence of element or attribute nodes with an IDREF value matching the value of one or more of the ID values supplied in $arg.

implicit-timezone

implicit-timezone() as xs:dayTimeDuration

Returns the value of the implicit timezone property from the dynamic context.

in-scope-prefixes

in-scope-prefixes(element()) as xs:string*

Returns the prefixes of the in-scope namespaces for an element node.

index-of

index-of(xs:anyAtomicType*, xs:anyAtomicType) as xs:integer*

index-of(xs:anyAtomicType*, xs:anyAtomicType, xs:string) as xs:integer*

Returns a sequence of positive integers giving the positions within the sequence $seq of items that are equal to $search.

innermost

innermost(node()*) as node()*

Returns every node within the input sequence that is not an ancestor of another member of the input sequence; the nodes are returned in document order with duplicates eliminated.

insert-before

insert-before(item()*, xs:integer, item()*) as item()*

Returns a sequence constructed by inserting an item or a sequence of items at a given position within an existing sequence.

lang

lang(xs:string?) as xs:boolean

lang(xs:string?, node()) as xs:boolean

This function tests whether the language of $node, or the context item if the second argument is omitted, as specified by xml:lang attributes is the same as, or is a sublanguage of, the language specified by $testlang.

last

last() as xs:integer

Returns the context size from the dynamic context.

local-name

local-name() as xs:string

local-name(node()?) as xs:string

Returns the local part of the name of $arg as an xs:string that is either the zero-length string, or has the lexical form of an xs:NCName.

local-name-from-QName

local-name-from-QName(xs:QName?) as xs:NCName?

Returns the local part of the supplied QName.

max

max(xs:anyAtomicType*) as xs:anyAtomicType?

max(xs:anyAtomicType*, xs:string) as xs:anyAtomicType?

Returns a value that is equal to the highest value appearing in the input sequence.

min

min(xs:anyAtomicType*) as xs:anyAtomicType?

min(xs:anyAtomicType*, xs:string) as xs:anyAtomicType?

Returns a value that is equal to the lowest value appearing in the input sequence.

name

name() as xs:string

name(node()?) as xs:string

Returns the name of a node, as an xs:string that is either the zero-length string, or has the lexical form of an xs:QName.

namespace-uri

namespace-uri() as xs:anyURI

namespace-uri(node()?) as xs:anyURI

Returns the namespace URI part of the name of $arg, as an xs:anyURI value.

namespace-uri-for-prefix

namespace-uri-for-prefix(xs:string?, element()) as xs:anyURI?

Returns the namespace URI of one of the in-scope namespaces for $element, identified by its namespace prefix.

namespace-uri-from-QName

namespace-uri-from-QName(xs:QName?) as xs:anyURI?

Returns the namespace URI part of the supplied QName.

node-name

node-name() as xs:QName?

node-name(node()?) as xs:QName?

Returns the name of a node, as an xs:QName.

number

number() as xs:double

number(xs:anyAtomicType?) as xs:double

Returns the value indicated by $arg or, if $arg is not specified, the context item after atomization, converted to an xs:double.

one-or-more

one-or-more(item()*) as item()+

Returns $arg if it contains one or more items. Otherwise, raises an error.

outermost

outermost(node()*) as node()*

Returns every node within the input sequence that has no ancestor that is itself a member of the input sequence; the nodes are returned in document order with duplicates eliminated.

parse-ietf-date

parse-ietf-date(xs:string?) as xs:dateTime?

Parses a string containing the date and time in IETF format, returning the corresponding xs:dateTime value.

parse-xml

parse-xml(xs:string?) as document-node(element(*))?

This function takes as input an XML document represented as a string, and returns the document node at the root of an XDM tree representing the parsed document.

parse-xml-fragment

parse-xml-fragment(xs:string?) as document-node()?

This function takes as input an XML external entity represented as a string, and returns the document node at the root of an XDM tree representing the parsed document fragment.

path

path() as xs:string?

path(node()?) as xs:string?

Returns a path expression that can be used to select the supplied node relative to the root of its containing document.

position

position() as xs:integer

Returns the context position from the dynamic context.

prefix-from-QName

prefix-from-QName(xs:QName?) as xs:NCName?

Returns the prefix component of the supplied QName.

random-number-generator

random-number-generator() as map(xs:string, item())

random-number-generator(xs:anyAtomicType) as map(xs:string, item())

Returns a random number generator, which can be used to generate sequences of random numbers.

remove

remove(item()*, xs:integer) as item()*

Returns a new sequence containing all the items of $target except the item at position $position.

resolve-QName

resolve-QName(xs:string?, element()) as xs:QName?

Returns an xs:QName value (that is, an expanded-QName) by taking an xs:string that has the lexical form of an xs:QName (a string in the form "prefix:local-name" or "local-name") and resolving it using the in-scope namespaces for a given element.

reverse

reverse(item()*) as item()*

Reverses the order of items in a sequence.

root

root() as node()

root(node()?) as node()?

Returns the root of the tree to which $arg belongs. This will usually, but not necessarily, be a document node.

serialize

serialize(item()*) as xs:string

serialize(item()*, item()?) as xs:string

This function serializes the supplied input sequence $arg as described in [xslt-xquery-serialization-31], returning the serialized representation of the sequence as a string.

static-base-uri

static-base-uri() as xs:anyURI?

This function returns the value of the Static Base URI property from the static context.

subsequence

subsequence(item()*, xs:double) as item()*

subsequence(item()*, xs:double, xs:double) as item()*

Returns the contiguous sequence of items in the value of $sourceSeq beginning at the position indicated by the value of $startingLoc and continuing for the number of items indicated by the value of $length.

sum

sum(xs:anyAtomicType*) as xs:anyAtomicType

sum(xs:anyAtomicType*, xs:anyAtomicType?) as xs:anyAtomicType?

Returns a value obtained by adding together the values in $arg.

tail

tail(item()*) as item()*

Returns all but the first item in a sequence.

unordered

unordered(item()*) as item()*

Returns the items of $sourceSeq in an implementation-dependent order.

unparsed-text

unparsed-text(xs:string?) as xs:string?

unparsed-text(xs:string?, xs:string) as xs:string?

The fn:unparsed-text function reads an external resource (for example, a file) and returns a string representation of the resource.

unparsed-text-available

unparsed-text-available(xs:string?) as xs:boolean

unparsed-text-available(xs:string?, xs:string) as xs:boolean

Because errors in evaluating the fn:unparsed-text function are non-recoverable, these two functions are provided to allow an application to determine whether a call with particular arguments would succeed.

unparsed-text-lines

unparsed-text-lines(xs:string?) as xs:string*

unparsed-text-lines(xs:string?, xs:string) as xs:string*

The fn:unparsed-text-lines function reads an external resource (for example, a file) and returns its contents as a sequence of strings, one for each line of text in the string representation of the resource.

uri-collection

uri-collection() as xs:anyURI*

uri-collection(xs:string?) as xs:anyURI*

Returns a sequence of xs:anyURI values representing the URIs in a URI collection.

zero-or-one

zero-or-one(item()*) as item()?

Returns $arg if it contains zero or one items. Otherwise, raises an error.

3 XSL Transformations (XSLT) Functions

This section lists all of the functions defined in the [XSLT 3.0] specification. Each function and operator is uniquely identified with a URI of the form: “http://www.w3.org/2005/xpath-functions#name” where name is the name of a function or operator, such as “system-property”: http://www.w3.org/2005/xpath-functions#system-property.

The normative definitions of these functions are in the [XSLT 3.0] specification. For convenience, a very brief, non-normative summary of each function is provided. For details, follow the link on the “Summary:” introductory text below each function.

accumulator-after

accumulator-after(xs:string) as item()*

Returns the post-descent value of the selected accumulator at the context node.

accumulator-before

accumulator-before(xs:string) as item()*

Returns the pre-descent value of the selected accumulator at the context node.

available-system-properties

available-system-properties() as xs:QName*

Returns a list of system property names that are suitable for passing to the system-property function, as a sequence of QNames.

collation-key

collation-key(xs:string) as xs:anyAtomicType

collation-key(xs:string, xs:string) as xs:anyAtomicType

Given a key and a collation, generates an internal value with the property that the internal value is the same for any two keys that compare equal under the given collation.

contains

contains(map(*), xs:anyAtomicType) as xs:boolean

Tests whether a supplied map contains an entry for a given key

copy-of

copy-of() as item()

copy-of(item()*) as item()*

Returns a deep copy of the sequence supplied as the $input argument, or of the context item if the argument is absent.

current

current() as item()

Returns the item that is the context item for the evaluation of the containing XPath expression

current-group

current-group() as item()*

Returns the group currently being processed by an xsl:for-each-group instruction.

current-grouping-key

current-grouping-key() as xs:anyAtomicType*

Returns the grouping key of the group currently being processed using the xsl:for-each-group instruction.

current-merge-group

current-merge-group() as item()*

current-merge-group(xs:string) as item()*

Returns the group of items currently being processed by an xsl:merge instruction.

current-merge-key

current-merge-key() as xs:anyAtomicType*

Returns the merge key of the merge group currently being processed using the xsl:merge instruction.

current-output-uri

current-output-uri() as xs:anyURI?

Returns the value of the .

deep-equal

deep-equal(item()*, item()*) as xs:boolean

deep-equal(item()*, item()*, xs:string) as xs:boolean

This function assesses whether two sequences are deep-equal to each other. The function as described here extends the definition of the XPath 3.0 deep-equal to explain how it should handle maps; it is intended to replace the existing deep-equal function at some stage in the future.

document

document(item()*) as node()*

document(item()*, node()) as node()*

Provides access to XML documents identified by a URI.

element-available

element-available(xs:string) as xs:boolean

Determines whether a particular instruction is or is not available for use. The function is particularly useful for calling within an [xsl:]use-when attribute (see ) to test whether a particular is available.

entry

entry(xs:anyAtomicType, item()*) as map(*)

Returns a map that contains a single entry (a key-value pair).

for-each

for-each(map(*), function(xs:anyAtomicType, item()*)) as item()*

Applies a supplied function to every entry in a map, returning the concatenation of the results.

function-available

function-available(xs:string) as xs:boolean

function-available(xs:string, xs:integer) as xs:boolean

Determines whether a particular function is or is not available for use. The function is particularly useful for calling within an [xsl:]use-when attribute (see ) to test whether a particular is available.

get

get(map(*), xs:anyAtomicType) as item()*

Returns the value associated with a supplied key in a given map.

json-to-xml

json-to-xml(xs:string) as document-node()

json-to-xml(xs:string, map(*)) as document-node()

Parses a string supplied in the form of a JSON text, returning the results in the form of an XML document node.

key

key(xs:string, xs:anyAtomicType*) as node()*

key(xs:string, xs:anyAtomicType*, node()) as node()*

Returns the nodes that match a supplied key value.

keys

keys(map(*)) as xs:anyAtomicType*

Returns a sequence containing all the keys present in a map

merge

merge(map(*)*) as map(*)

Returns a map that combines the entries from a number of existing maps.

put

put(map(*), xs:anyAtomicType, item()*) as map(*)

Returns a map containing all the contents of the supplied map, but with an additional entry, which replaces any existing entry for the same key.

regex-group

regex-group(xs:integer) as xs:string

Returns the string captured by a parenthesized subexpression of the regular expression used during evaluation of the xsl:analyze-string instruction.

remove

remove(map(*), xs:anyAtomicType) as map(*)

Returns a map containing all the entries from a supplied map, except (typically) one.

same-key

same-key(xs:anyAtomicType, xs:anyAtomicType) as xs:boolean

Determines whether two atomic values can coexist as separate keys within a map.

size

size(map(*)) as xs:integer

Returns the number of entries in the supplied map.

snapshot

snapshot() as item()

snapshot(item()*) as item()*

Returns a copy of a sequence, retaining copies of the ancestors and descendants of any node in the input sequence, together with their attributes and namespaces.

stream-available

stream-available(xs:string?) as xs:boolean

Determines, as far as possible, whether a document is available for streamed processing using xsl:stream.

system-property

system-property(xs:string) as xs:string

Returns the value of a system property

type-available

type-available(xs:string) as xs:boolean

Used to control how a stylesheet behaves if a particular schema type is or is not available in the static context.

unparsed-entity-public-id

unparsed-entity-public-id(xs:string) as xs:string

unparsed-entity-public-id(xs:string, node()) as xs:string

Returns the public identifier of an unparsed entity

unparsed-entity-uri

unparsed-entity-uri(xs:string) as xs:anyURI

unparsed-entity-uri(xs:string, node()) as xs:anyURI

Returns the URI (system identifier) of an unparsed entity

xml-to-json

xml-to-json(node()) as xs:string

xml-to-json(node(), map(*)) as xs:string

Converts an XML tree, whose format corresponds to the XML representation of JSON defined in this specification, into a string conforming to the JSON grammar.

4 XML Schema

Two functions, fn:analyze-string and fn:json-to-xml, return results that are always valid according to a defined XSD schema. A third function, fn:xml-to-json, requires input that is valid according to this schema.

The target namespace of these schema components is http://www.w3.org/2005/xpath-functions.

These schema components define the XML syntax of the result returned by fn:json-to-xml as defined in [XSLT 3.0]. They are specified in a schema document located at http://www.w3.org/2014/11/xslt-30/schema-for-json.xsd.