Difference between revisions of "Utility Module"

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This [[Module Library|XQuery Module]] contains some utility and helper functions.
 
This [[Module Library|XQuery Module]] contains some utility and helper functions.
  
−
With {{Announce|Version 11}}, many functions have been removed as they are now part of the official specification:
+
With {{Announce|Version 11}}, many functions have been removed in favor of new features of XQuery 4:
  
 
{|
 
{|
Line 19: Line 19:
 
| {{Code|util:duplicates}}
 
| {{Code|util:duplicates}}
 
| [https://qt4cg.org/specifications/xpath-functions-40/Overview.html#func-duplicate-values <code>fn:duplicate-values</code>]
 
| [https://qt4cg.org/specifications/xpath-functions-40/Overview.html#func-duplicate-values <code>fn:duplicate-values</code>]
−
|- valign="top"
 
−
| {{Code|util:if}}
 
−
| <code>if($test) { $then } else { $else }</code> (with the new syntax, the else branch is optional)
 
 
|- valign="top"
 
|- valign="top"
 
| {{Code|util:init}}
 
| {{Code|util:init}}
Line 36: Line 33:
 
|- valign="top"
 
|- valign="top"
 
| {{Code|util:map-entries}}
 
| {{Code|util:map-entries}}
−
| [https://qt4cg.org/specifications/xpath-functions-40/Overview.html#func-map-pairs <code>map:pairs</code>]
+
| [https://qt4cg.org/specifications/xpath-functions-40/Overview.html#func-map-entries <code>map:entries</code>]
 
|- valign="top"
 
|- valign="top"
 
| {{Code|util:map-values}}
 
| {{Code|util:map-values}}
Line 52: Line 49:
 
All functions and errors in this module and errors are assigned to the <code><nowiki>http://basex.org/modules/util</nowiki></code> namespace, which is statically bound to the {{Code|util}} prefix.<br/>
 
All functions and errors in this module and errors are assigned to the <code><nowiki>http://basex.org/modules/util</nowiki></code> namespace, which is statically bound to the {{Code|util}} prefix.<br/>
  
−
=Range Conditions=
+
=Conditions and Ranges=
 +
 
 +
==util:if==
 +
 
 +
{| width='100%'
 +
|- valign="top"
 +
| width='120' | '''Signature'''
 +
|<pre>util:if(
 +
  $condition  as item()*,
 +
  $then      as item()*,
 +
  $else      as item()*  := ()
 +
) as item()*</pre>
 +
|- valign="top"
 +
| '''Summary'''
 +
|Alternative writing for the if/then/else expression:
 +
* If the ''effective boolean value'' of {{Code|$condition}} is true, the {{Code|$then}} branch will be evaluated.
 +
* Otherwise, {{Code|$else}} will be evaluated. If the third argument is omitted, an empty sequence will be returned.
 +
|- valign="top"
 +
| '''Examples'''
 +
|
 +
* <code>util:if(true(), 123, 456)</code> returns {{Code|123}}.
 +
* <code>util:if(0, 'wrong!')</code> returns an empty sequence.
 +
|}
  
 
==util:count-within==
 
==util:count-within==
Line 67: Line 86:
 
| '''Summary'''
 
| '''Summary'''
 
|Checks if the specified {{Code|$sequence}} has at least {{Code|$min}} and, optionally, at most {{Code|$max}} items. Equivalent to:
 
|Checks if the specified {{Code|$sequence}} has at least {{Code|$min}} and, optionally, at most {{Code|$max}} items. Equivalent to:
−
<syntaxhighlight lang="xquery">
+
<pre lang='xquery'>
 
let $count := count($sequence)
 
let $count := count($sequence)
 
return $count >= $min and $count <= $max
 
return $count >= $min and $count <= $max
−
</syntaxhighlight>
+
</pre>
 
|- valign="top"
 
|- valign="top"
 
| '''Examples'''
 
| '''Examples'''
Line 91: Line 110:
 
| '''Summary'''
 
| '''Summary'''
 
|Returns items from {{Code|$sequence}}, starting at position {{Code|$first}} and ending at {{Code|$last}}. Equivalent to:
 
|Returns items from {{Code|$sequence}}, starting at position {{Code|$first}} and ending at {{Code|$last}}. Equivalent to:
−
<syntaxhighlight lang="xquery">
+
<pre lang='xquery'>
 
subsequence($sequence, $first, $last - $first + 1)
 
subsequence($sequence, $first, $last - $first + 1)
−
</syntaxhighlight>
+
</pre>
 
|- valign="top"
 
|- valign="top"
 
| '''Examples'''
 
| '''Examples'''
Line 113: Line 132:
 
| '''Summary'''
 
| '''Summary'''
 
|Returns nodes in ''distinct document order'': duplicate nodes will be removed, and the remaining nodes will be returned in [https://www.w3.org/TR/xquery-31/#dt-document-order document order]. As results of path expressions are brought distinct document order before they are returned, the function is equivalent to:
 
|Returns nodes in ''distinct document order'': duplicate nodes will be removed, and the remaining nodes will be returned in [https://www.w3.org/TR/xquery-31/#dt-document-order document order]. As results of path expressions are brought distinct document order before they are returned, the function is equivalent to:
−
<syntaxhighlight lang="xquery">
+
<pre lang='xquery'>
 
$nodes/self::node()
 
$nodes/self::node()
−
</syntaxhighlight>
+
</pre>
 
|}
 
|}
  
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| '''Summary'''
 
| '''Summary'''
 
|Returns the document nodes of the specified {{Code|$nodes}}. The path expression <code>/abc</code> is internally represented as <code>util:root(.)/abc</code>. Equivalent to:
 
|Returns the document nodes of the specified {{Code|$nodes}}. The path expression <code>/abc</code> is internally represented as <code>util:root(.)/abc</code>. Equivalent to:
−
<syntaxhighlight lang="xquery">
+
<pre lang='xquery'>
 
$nodes ! /
 
$nodes ! /
−
</syntaxhighlight>
+
</pre>
 
|}
 
|}
  
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|
 
|
 
* Remove all namespaces from an element and its descendants:
 
* Remove all namespaces from an element and its descendants:
−
<syntaxhighlight lang="xquery">
+
<pre lang='xquery'>
 
util:strip-namespaces(<xml xmlns='uri' xmlns:prefix='uri2' prefix:name='value'><prefix:child/></xml>)
 
util:strip-namespaces(<xml xmlns='uri' xmlns:prefix='uri2' prefix:name='value'><prefix:child/></xml>)
  
 
(: yields :)
 
(: yields :)
 
<xml name='value'><child/></xml>
 
<xml name='value'><child/></xml>
−
</syntaxhighlight>
+
</pre>
 
* Remove all default namespaces:
 
* Remove all default namespaces:
−
<syntaxhighlight lang="xquery">
+
<pre lang='xquery'>
 
<xml xmlns='uri1'><child xmlns='uri2'/></xml>
 
<xml xmlns='uri1'><child xmlns='uri2'/></xml>
 
=> util:strip-namespaces('')
 
=> util:strip-namespaces('')
−
</syntaxhighlight>
+
</pre>
 
|}
 
|}
  
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;Version 9.5
 
;Version 9.5
−
* Added: {{Function||util:intersperse}}, {{Function||util:within}}, {{Function||util:duplicates}}, {{Function||util:array-members}}, {{Function||util:array-values}}, {{Function||util:map-entries}}, {{Function||util:map-values}}
+
* Added: {{Code|util:intersperse}}, {{Code|util:within}}, {{Code|util:duplicates}}, {{Code|util:array-members}}, {{Code|util:array-values}}, {{Code|util:map-entries}}, {{Code|util:map-values}}
−
* Updated: {{Function||util:replicate}}: Third argument added.
+
* Updated: {{Code|util:replicate}}: Third argument added.
  
 
;Version 9.4
 
;Version 9.4
Line 193: Line 212:
  
 
;Version 9.2
 
;Version 9.2
−
* Added: {{Function||util:chars}}, {{Function||util:init}}
+
* Added: {{Code|util:chars}}, {{Code|util:init}}
−
* Updated: {{Function||util:item}}, {{Function||util:last}}, {{Function||util:range}} renamed (before: {{Code|util:item-at}}, {{Code|util:item-range}}, {{Code|util:last-from}})
+
* Updated: {{Code|util:item}}, {{Code|util:last}}, {{Function||util:range}} renamed (before: {{Code|util:item-at}}, {{Code|util:item-range}}, {{Code|util:last-from}})
  
 
;Version 9.1
 
;Version 9.1
−
* Added: {{Function||util:if}}, {{Function||util:or}}
+
* Added: {{Function||util:if}}, {{Code|util:or}}
  
 
;Version 9.0
 
;Version 9.0
−
* Added: {{Function||util:replicate}}
+
* Added: {{Code|util:replicate}}
  
 
The Module was introduced with Version 8.5.
 
The Module was introduced with Version 8.5.

Latest revision as of 14:36, 5 December 2023

This XQuery Module contains some utility and helper functions.

With Version 11, many functions have been removed in favor of new features of XQuery 4:

BaseX 10 XQuery 4
util:array-members array:members
util:array-values array:values
util:chars fn:characters
util:duplicates fn:duplicate-values
util:init fn:trunk
util:intersperse fn:intersperse
util:item fn:items-at
util:last fn:foot
util:map-entries map:entries
util:map-values map:values
util:or $expr1 otherwise $expr2
util:replicate fn:replicate

Conventions[edit]

All functions and errors in this module and errors are assigned to the http://basex.org/modules/util namespace, which is statically bound to the util prefix.

Conditions and Ranges[edit]

util:if[edit]

Signature 
util:if(
  $condition  as item()*,
  $then       as item()*,
  $else       as item()*  := ()
) as item()*
Summary Alternative writing for the if/then/else expression:
  • If the effective boolean value of $condition is true, the $then branch will be evaluated.
  • Otherwise, $else will be evaluated. If the third argument is omitted, an empty sequence will be returned.
Examples
  • util:if(true(), 123, 456) returns 123.
  • util:if(0, 'wrong!') returns an empty sequence.

util:count-within[edit]

Signature 
util:count-within(
  $sequence  as item()*,
  $min       as xs:integer,
  $max       as xs:integer  := ()
) as xs:boolean
Summary Checks if the specified $sequence has at least $min and, optionally, at most $max items. Equivalent to: 
let $count := count($sequence)
return $count >= $min and $count <= $max
Examples
  • util:count-within(('a', 'b', 'c'), 2) returns true.
  • util:count-within((1 to 1000000000)[. < 10], 3, 6) returns true.

util:range[edit]

Signature 
util:range(
  $sequence  as item()*,
  $first     as xs:double,
  $last      as xs:double
) as item()*
Summary Returns items from $sequence, starting at position $first and ending at $last. Equivalent to: 
subsequence($sequence, $first, $last - $first + 1)
Examples
  • util:range(//item, 11, 20) returns all path results from (if available) position 11 to 20.

Node Functions[edit]

util:ddo[edit]

Signature 
util:ddo(
  $nodes  as node()*
) as node()*
Summary Returns nodes in distinct document order: duplicate nodes will be removed, and the remaining nodes will be returned in document order. As results of path expressions are brought distinct document order before they are returned, the function is equivalent to: 
$nodes/self::node()

util:root[edit]

Signature 
util:root(
  $nodes  as node()*
) as document-node()*
Summary Returns the document nodes of the specified $nodes. The path expression /abc is internally represented as util:root(.)/abc. Equivalent to: 
$nodes ! /

util:strip-namespaces[edit]

Signature 
util:strip-namespaces(
  $node      as node(),
  $prefixes  as xs:string*  := ()
) as node()
Summary Removes namespaces with the specified $prefixes from the supplied $node. An empty string can be supplied to remove the default namespace. If no prefixes are specified, all namespaces will be removed.
Examples
  • Remove all namespaces from an element and its descendants:
util:strip-namespaces(<xml xmlns='uri' xmlns:prefix='uri2' prefix:name='value'><prefix:child/></xml>)

(: yields :)
<xml name='value'><child/></xml>
  • Remove all default namespaces:
<xml xmlns='uri1'><child xmlns='uri2'/></xml>
=> util:strip-namespaces('')

Errors[edit]

Code Description
negative The specified number is negative.

Changelog[edit]

Version 11.0
  • Removed: util:array-members, util:array-values, util:chars, util:duplicates, util:init, util:intersperse, util:item, util:last, util:map-entries, util:map-values, util:replicate
Version 9.7
Version 9.5
  • Added: util:intersperse, util:within, util:duplicates, util:array-members, util:array-values, util:map-entries, util:map-values
  • Updated: util:replicate: Third argument added.
Version 9.4
Version 9.3
Version 9.2
  • Added: util:chars, util:init
  • Updated: util:item, util:last, util:range renamed (before: util:item-at, util:item-range, util:last-from)
Version 9.1
Version 9.0
  • Added: util:replicate

The Module was introduced with Version 8.5.

Retrieved from "http://docs.basex.org/index.php?title=Utility_Module&oldid=16918"