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New functions in 2.0 / 3.0 / 3.1

The 1.0 function library is small — count, string, concat, substring, translate, and a handful more. Every version since has added to it. The big additions get their own pages (regex, dates, higher-order, maps & arrays, JSON, text I/O); this page is a reference for the smaller but constantly-useful functions that don't each need a chapter.

The version column is when the function appeared (2.0, 3.0, 3.1). All of these work in the free Saxon-HE.

Working with sequences

Function Does Ver
distinct-values($seq) drop duplicate atomic values 2.0
index-of($seq, $v) positions where $v occurs 2.0
subsequence($seq, $start [, $len]) a slice, 1-based 2.0
reverse($seq) reverse order 2.0
insert-before / remove($seq, $pos …) add / drop items by position 2.0
head($seq) / tail($seq) first item / everything-but-first 3.0
exists($seq) / empty($seq) is the sequence non-empty / empty 2.0
deep-equal($a, $b) recursive value+structure equality 2.0 
<xsl:value-of select="distinct-values(/catalog/cd/@genre)"/>   <!-- country pop rock -->
<xsl:value-of select="head(/catalog/cd)/title"/>               <!-- Empire Burlesque -->

Aggregates and numbers

Function Does Ver
avg($seq) / min($seq) / max($seq) average / smallest / largest 2.0
abs($n) absolute value 2.0
round-half-to-even($n [, $p]) banker's rounding 2.0
format-integer($n, $picture) 1 → i, one, 001, … 3.0
random-number-generator([$seed]) a map yielding pseudo-random numbers 3.1 
<xsl:value-of select="avg(/catalog/cd/xs:decimal(price))"/>    <!-- 10.233… -->
<xsl:value-of select="format-integer(4, 'I')"/>                <!-- IV -->

Strings

Most string work lives on the regex & strings page; the essentials:

Function Does Ver
string-join($seq [, $sep]) concatenate with a separator 2.0
upper-case / lower-case($s) case conversion 2.0
normalize-unicode($s) Unicode normalisation (NFC, …) 2.0
string-to-codepoints / codepoints-to-string string ⇄ code points 2.0
tokenize / replace / matches see regex 2.0

Nodes and documents

Function Does Ver
doc($uri) / doc-available($uri) load an XML document / test it loads 2.0
collection($uri) / uri-collection($uri) a set of documents / their URIs 2.0 / 3.0
path($node) the node's XPath location, as a string 3.0
has-children($node) does it have child nodes 3.0
innermost($seq) / outermost($seq) strip ancestors / descendants from a node set 3.0
unparsed-text / parse-xml / serialize text & string I/O 2.0 / 3.0 
<xsl:if test="doc-available('prices.xml')">
  <xsl:value-of select="doc('prices.xml')/prices/total"/>
</xsl:if>

Diagnostics

Function Does Ver
trace($value, $label) log $value to the processor's trace output, return it unchanged 2.0
error([$code [, $desc]]) abort with an error — see error handling 2.0

trace is the printf-debugging of XSLT: wrap any sub-expression in it and watch what flows through without altering the result.

The bigger additions (their own pages)

For completeness, the major library growth covered elsewhere:

  • Regex & strings — tokenize, replace, matches → regex
  • Dates — format-date, current-dateTime, the *-from-* accessors → dates and times
  • Higher-order — for-each, filter, fold-left/-right, sort, apply → higher-order functions
  • Maps & arrays — the map:* and array:* namespaces → maps and arrays
  • JSON — parse-json, json-doc, json-to-xml, xml-to-json → JSON

Where to go next