binary search in xquery

gistfile1.xquery

xquery version "1.0-ml";

declare function local:binary($min,$max,$number){
let $middle := round( (($max - $min) div 2) + $min )
return
if($middle eq $number)
then $number
else 
if($middle lt $number)
then local:binary($middle,$max,$number)
else local:binary($min,$middle,$number)
};

let $min := 0
let $max := 1000000
let $number := (xdmp:random($max - $min))

return local:binary($min,$max,$number)