How to find a word within text using XSLT 2.0 and REGEX (which doesn't have \b word boundary)?

Question

I am attempting to scan a string of words and look for the presence of a particular word(case insensitive) in an XSLT 2.0 stylesheet using REGEX.

I have a list of words that I wish to iterate over and determine whether or not they exist within a given string.

I want to match on a word anywhere within the given text, but I do not want to match within a word (i.e. A search for foo should not match on "food" and a search for bar should not match on "rebar").

XSLT 2.0 REGEX does not have a word boundary(\b), so I need to replicate it as best I can.

Answer 1

This is what I have come up with so far:

    <!-- 
         [^a-zA-Z] attempts to prevent matching within words when used as a prefix or suffix to a regex expression
     -->
 <xsl:variable name="b" select="'[^a-zA-Z]'" />

<!-- 
        ^ ensures that the leading word can be matched 
        $ ensures that trailing word will be matched
 -->
<xsl:if test="matches($prose, concat('^',$word, $b),'i') or matches($prose, concat($b, $word, '$'),'i') or matches($prose, concat($b, $word, $b),'i')">

        <!--We found the word -->

</xsl:if>

This seems to be working reasonably well, but I am repeating virtually the same expression 3 times, which is not very efficient.

Answer 2

You can use alternation to avoid repetition:

<xsl:if test="matches($prose, concat('(^|\W)', $word, '($|\W)'),'i')">

Answer 3

If your XSLT 2.0 processor is Saxon 9 then you can use Java regular expression syntax (including \b) with the functions matches, tokenize and replace by starting the flag attribute with an exclamation mark:

<xsl:value-of select="matches('all foo is bar', '\bfoo\b', '!i')"/>

Michael Kay mentioned that option recently on the XSL mailing list.