twitter skeleton excerise

skeleton.xq

declare function fetch-tweets($keyword as xs:string) as node()* {
  let $uri := "http://search.twitter.com/search.atom?geocode=52.1583,4.49306,200km&rpp=100&q=XXX"  
  return (: TODO replace XXX by keyword, fetch real entrys with doc() from uri :)
    <entry><title>oops, I did it again</title><uri>http://twitter.com/britneyspears</uri><location>Hollywood</location></entry>
};

declare function get-geo($placename as xs:string) as xs:string {
  let $uri :=  (:replace XXX by placename :) 
  "http://where.yahooapis.com/v1/places.q(&quot;XXX&quot;);count=1?format=xml&amp;appid=oWI.U034EMJO6CnsA4vFEvJ5oYEKsoD0qLIRfcoEKOLLTqv9bh6jBHZn9GhdRA--",
      $centroid := 
        <centroid><latitude>52.33</latitude><longitude>4.86</longitude></centroid> (:TODO get 1st centroid :)
  return "42,42" (: TODO use $centroid node to create a comma separated string of "latitude,longitude" :)
};

declare function safe-geo($placename as xs:string) as xs:string { (: protect Yahoo against strange locations :)
  let $safename := translate($placename,";:=+&amp;{}[]<>!@#$%^*=+\/|'&quot;","     ()()()")
  return if (contains($placename,":")) then substring-after($placename,":") else get-geo($safename)
};

declare function order-tweets($keyword as xs:string) as node()* {
  let $tweets := fetch-tweets($keyword),
      $retweets := (), (: TODO select retweets from $tweets :)
      $newtweets := () (: TODO group unique retweets keeping 1 example for each, ordering those by count descending :)
  return ($newtweets, $tweets except $retweets) (: note the use of set operator "except" :)
};

declare function get-tweets($keyword as xs:string) as node() {
<result keyword="{$keyword}">{
  let $tweets := order-tweets($keyword) (: TODO: restrict to the first 9 :)
  for $tweet in $tweets
  let (: TODO: get info from the $tweet rather than this bogus stuff :)
      $geo := "52.334782,4.866480",
      $uri := "http://twitter.com/britneyspears",
      $txt := "oops, I did it again",
      $nr := 1 (: TODO determine the tweet-nr where this location occurs first, in the $tweets sequence :)
   return <tweet nr="{$nr}" geo="{$geo}" user="{$uri}" cnt="">{$txt}</tweet>
}</result>
};

(: sequence of example queries :)

(
 count(fetch-tweets("Rutte")),
 count(order-tweets("Rutte")),
 get-geo("Vrije Universiteit Amsterdam"),
 get-tweets("Rutte")
)