note sundialsvc4 <p> The magic voodoo you are looking for is: &nbsp; <tt><b>qr/<i>some_expression</i>/</b></tt>. </p><p> This operator compiles a regular expression that is made from <tt><i>some_string</i></tt>. </p><p> When constructing the string, be careful: &nbsp; you might be tempted to use interpolation (double-quotes...) but this will cause the &ldquo;rabbit-food&rdquo; of the regex syntax itself to be turned into escape-characters. </p><p> Furthermore, you might find that you can successfully put a string-variable reference <i>into</i> the regular expression string <i>(i.e.</i> without using <tt>qr//</tt>), and find that it is properly interpolated. &nbsp; If you simply want to substitute &ldquo;a particular string to search for&rdquo; into an otherwise-fixed expression, this is one way to do that. </p><p> If the regexes to be used are truly arbitrary, however, you will want to use <tt>qr//</tt>, and to enclose that statement in an <tt>eval</tt> block to trap runtime errors caused by invalid regex syntax. </p> 870806 870806