XSLT, 2nd Edition

[XPath] Anchors

In XML Schema, regular expressions are anchored; in other words, the regular expression is assumed to start at the beginning of the text and end at the end of the text. That means the expression abc matches only the three-character string abc. If there are any extra characters before or after the letters abc, XML Schema does not consider the string a match.

The regular expression language in XPath 2.0 doesn’t work that way. When we use any of the regular expression functions or elements, a string matches if it contains the regular expression anywhere inside it. In other words, using XPath’s regular expression language, both abc and I know my abc's match the expression abc. XPath provides the traditional anchor operators used in other regular expression languages. The caret (^) matches the start of the string, while the dollar sign ($) matches the end of the string. If multiline mode is on (-m), the caret matches the start of the string and any character immediately following a newline. Similarly, in multiline mode, the dollar sign matches the end of the string and any character immediately before a newline.

Here’s an example that illustrates how the anchors work:

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

  <xsl:output method="text"/>

  <xsl:template match="/">
    <xsl:text>matches('abcdefghij', 'cde'): </xsl:text>
    <xsl:value-of 
      select="if (matches('abcdefghij', 'cde')) then 'It''s ...