(def expand-metafn-call (f args)
      (if (is (car f) 'compose)
           ((afn (fs)
              (if (caris (car fs) 'compose)            ; nested compose
                   (self (join (cdr (car fs)) (cdr fs)))
                  (cdr fs)
                   (list (car fs) (self (cdr fs)))
                  (cons (car fs) args)))
            (cdr f))
          (is (car f) 'no)
           (err "Can't invert " (cons f args))
           (cons f args)))