<pre class="brush:xquery">
declare %rest:path("/check/{$user}") function page:check($user) {
if($user = ('jack', 'lisa'))
then 'User exists'
};
declare % rest:error("err:user") %rest:error-param("description", "{$user}") function page:user-error($user) {
'User "' || $user || '" is unknown'
};