XSLT, 2nd Edition

[XPath] Reluctant Quantifiers

By default, a regular expression or subexpression matches the longest possible string. The quantifiers +, *, and ? match as many characters as possible. Adding a question mark to the end of a quantifier causes the expression or subexpression to match the shortest possible string. The quantifiers are modified as follows:

a+?

Matches a once

a??

Matches a, either once or not at all (works only in the matches() function; more on this later in this section)

a*?

Matches a, zero times or once (works only in the matches() function; more on this later in this section)

a{x}?

Matches a, exactly x times (in this case the reluctant qualifier doesn’t change anything)

a{x,}?

Matches a exactly x times (the comma is irrelevant—a reluctant quantifier matches only the minimum length)

a{x,y}?

Matches a exactly x times (the second number, y, is irrelevant—a reluctant quantifier matches only the minimum length)

As an example, we’ll use the replace() function. We’ll put square brackets around each match in the original string. The normal quantifier and the reluctant quantifier work differently, as we’ll see. Here’s the stylesheet:

<?xml version="1.0" encoding="utf-8"?>
<!-- reluctant.xsl -->
<xsl:stylesheet version="2.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

  <xsl:output method="text"/>

  <xsl:template match="/">
    <xsl:text>Original string: 'Call me at 19195551212'&#xA;</xsl:text>
    <xsl:text>  replace($x, '([0-9]+)', '[$1]'):&#xA;    </xsl:text>
    <xsl:value-of 
 select="replace('Call ...