filtering documents based on custom date format in XQuery

date.xquery

for $doc in //Document
 let $datestr := $doc/@time
 let $datearr := tokenize($datestr, '/')
 let $year := $datearr[3]
 let $month := format-number(xs:int($datearr[2]), '#00')
 let $day := format-number(xs:int($datearr[1]), '#00')
 let $dateisostr := concat($year, '-', $month, '-', $day)
 where $dateisostr > '2010-06-01' and $dateisostr < '2011-01-01'
(:
 let $date := xs:date($dateisostr)
 where $date > xs:date('2010-06-01') and $date < xs:date('2011-01-01')
:)
return $doc