(defmacro apps
  (case (op x) x)
  (case (op x1 x2 xs ...) (apps op (op x1 x2) xs ...)))

(defmacro appsr
  (case (op x) x)
  (case (op x xs ...) (op x (appsr op xs ...))))

(defmacro list
  (case (xs ...) (appsr list/cons xs ... Nil)))

(defmacro +s (case (xs ...) (apps + xs ...)))