Converts an integer to a corresponding sequence of words

convert.xqy

xquery version "3.0";

(:~
: Converts an integer to a corresponding sequence of words
: @author Clifford Anderson 
: @version 1.0
:
:)

(: This function is adapted from a function by Nelson Wells :)
(: http://nelsonwells.net/2012/03/convert-an-integer-to-a-sequence-of-digits-in-xquery/ :)
declare function local:number-to-seq($num as xs:integer) as xs:integer* 
{
  if($num gt 9) then
    (
      local:number-to-seq(xs:integer(fn:floor($num div 10))),
      xs:integer(fn:floor($num mod 10))
    )
  else
    $num
};

declare function local:int-to-string($num as xs:integer) as xs:string* {
  for $item in local:number-to-seq($num)
  return 
    switch($item)
      case 0 	return "zero"
      case 1 	return "one"
      case 2 	return "two"
      case 3 	return "three"
      case 4 	return "four"
      case 5 	return "five"
      case 6 	return "six"
      case 7 	return "seven"
      case 8 	return "eight"
      case 9 	return "nine"
      default	return "NAN"
};

local:int-to-string(0)