the 'naked' Y-combinator in XQuery 3.0 using classic factorial example, providing the ability to recurse within anonymous functions

gistfile1.xquery

xquery version "3.0";

let $makeFact := function($givenFact) {
      let $fact := function($n) {
	    if( $n lt 2 ) 
            then 1
	    else $n * $givenFact($n - 1)
       }
return $fact
}

let  $makeRealFact := function($makeFact) {
	let $getNextTryFact := function($getNextTryFactRef) {
		let $tryFact := function($n) {
			let $nextTryFact := $getNextTryFactRef($getNextTryFactRef)
			let $result := $nextTryFact($n)
			return $result
		}
		let $nextTryFact := $makeFact($tryFact)
		return $nextTryFact
	}
	return $getNextTryFact($getNextTryFact)
}

let $factorial := $makeRealFact($makeFact)

return $factorial(5)