Use of privileged methods in the default wiki

Hi all, While implementing XWIKI-1264 <http://jira.xwiki.org/jira/browse/XWIKI-1264>(Transform the AllDocs page into an index with A-Z links to show docs by letter) I faced the following problem : I wanted to show letter links only for relevant letters (for the user not being faced with empty result for letters that has no document related). But how to search for distinct letters from the wiki ? 1- we use $xwiki.search("select distinct substring(doc.name, 1, 1) from XWikiDocument as doc where 1=1") but then, the document depends on a privileged API, if someone without programming right edit and saves it, it breaks. 2- we implement a method like "getDocumentsIndex()" in the XWiki API but as Vincent says, it's not really generic, it applies only on this case. 3- we call a groovy script that holds privileged API calls (possibly the whole wiki privileged calls) but, it's not really clean either, and it's too bad we have to maintain two docs for a small script like the AllDocs one. As for now we found none of this option good enough, there will be all letters proposed... with the possibility the users faces an empty result page. What do you think? Are there any other option ? I think this problem leads to the more generic problem of how to handle privileged calls in the default wiki. Jerome.