question on XML Twig and XPath query

stevensun has asked for the wisdom of the Perl Monks concerning the following question:

I've got an XML file and need to parse out the measurements for a particular product. The measurement type is determined by <c093> tag (01- height 02-width 03-length 04-weight). I try to query it with this code but the Xpath query keeps saying "error in xpath expression" even though it works in my XML editor.
the code is:

use strict;
use XML::Twig;

use XML::XPath;
use XML::XPath::XMLParser;

my $twig= new XML::Twig(  TwigHandlers => { product => \&product }  );
+                    

$twig->parsefile("file.xml");

my @height = $twig->get_xpath ('//measure[string(c093)="01"]');  #if i
+ want to get the length
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****************************************************** the xml file is:

<message>
<product>
        <measure>
            <c093>01</c093>
            <c094>229.0</c094>
            <c095>mm</c095>
        </measure>
        <measure>
            <c093>02</c093>
            <c094>152.0</c094>
            <c095>mm</c095>
        </measure>
        <measure>
            <c093>03</c093>
            <c094>15.0</c094>
            <c095>mm</c095>
        </measure>
        <measure>
            <c093>08</c093>
            <c094>24</c094>
            <c095>oz</c095>
        </measure>

</product>
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20060311 Janitored by Corion: Added code tags around code and data

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Re: question on XML Twig and XPath query by Aristotle (Chancellor) on Mar 11, 2006 at 07:08 UTC
The XML::Twig documentation says this: XML::Twig implements a subset of XPath through the `get_xpath` method. If you want to use the whole XPath power, then you can use `XML::Twig::XPath` instead. In this case `XML::Twig` uses `XML::XPath` to execute XPath queries. You will of course need `XML::XPath` installed to be able to use `XML::Twig::XPath`. so do that. Makeshifts last the longest.	[reply]
Re^2: question on XML Twig and XPath query by stevensun (Initiate) on Mar 14, 2006 at 08:07 UTC
Aristotle, thanks for your help! Corion, thanks for cleaning up my XML!	[reply]