XQuery Working Group Challenge

convert.xqy

xquery version "3.1";

(: FUNCTION: Whether all the values in a sequence are distinct http://www.xqueryfunctions.com/xq/functx_are-distinct-values.html :)
declare namespace functx = "http://www.functx.com";
declare function functx:are-distinct-values
	($seq as xs:anyAtomicType* ) as xs:boolean {
	count(distinct-values($seq)) = count($seq)};

(: Converts sentences into verses and returns verses containing duplicate lemmata :)

(: Official release of the PROIEL treebank of ancient Indo-European languages :)
let $uri := "https://raw.githubusercontent.com/proiel/proiel-treebank/master/latin-nt.xml" 
let $doc := fn:doc($uri)
for $citation in fn:distinct-values(fn:data($doc//token/@citation-part))
	let $tokens := $doc//token[./@citation-part = $citation]
		where fn:not(functx:are-distinct-values($tokens/@lemma))
			return element verse {
				attribute citation {$citation},
				fn:data($tokens[./@citation-part = $citation]/@form)}