This code sample is adapted from Clifford B. Anderson and Joseph C. Wicentowski, XQuery for Humanists (College Station: Texas A&M University Press, 2020), 115. Download this code sample in its raw form. View the source on GitHub.

xquery version "3.1";

declare namespace tei = "";

declare function local:make-tei-title(
    $title as xs:string,
    $subtitle as xs:string?
    ) as element(tei:title) {
    (: the function will go here :)