return signature of apputil:resolve and apputil:resolve-abbrev :

[christophe-g]

Tiny modification in apputil.xql:
As apputil:resolve and apputil:resolve-abbrev can return an empty sequence, the signature should be xs:string? instead of just xs:string as it is now.
Cheers,
C.

(:~
 : Try to find an application by its unique name and return the relative path to which it
 : has been deployed inside the database.
 : 
 : @param $pkgURI unique name of the application
 : @return database path relative to the collection returned by repo:get-root() 
 : or the empty sequence if the package could not be found or is not deployed into the db
 :)
declare function apputil:resolve($uri as xs:string) as xs:string **?** {
    let $path := collection(repo:get-root())//expath:package[@name = $uri]
    return
        if ($path) then
            substring-after(util:collection-name($path), repo:get-root())
        else
            ()
};

(:~
 : Try to find an application by its abbreviated name and return the relative path to which it
 : has been deployed inside the database.
 : 
 : @param $pkgURI unique name of the application
 : @return database path relative to the collection returned by repo:get-root() 
 : or the empty sequence if the package could not be found or is not deployed into the db
 :)
declare function apputil:resolve-abbrev($abbrev as xs:string) as xs:string **?** {
    let $path := $apputil:PACKAGES($abbrev)
    return
        if ($path) then
            substring-after($path, repo:get-root())
        else
            ()
};