;; Try it out
;; $until(Your next Birthday)
;; $since(Your last Birthday)
until {
if ($1) { return $iif($left($dur($calc($ctime($1) - $ctime)),1) != -,$dur($calc($ctime($1) - $ctime)),0) }
}
since {
if ($1) { return $iif($left($dur($calc($ctime - $ctime($1))),1) != -,$dur($calc($ctime - $ctime($1))),0) }
}