add-hook-examples.nydp

(examples-for add-hook
  ("registers a function to be run in response to a particular event"
   (with (x nil y nil z nil)
     (add-hook 'pile-it-up
               (fn (thing)
                   (= x (cons thing x))))
     (add-hook 'why-not
               (fn (thing)
                   (= y (cons thing y))))
     (add-hook 'pile-it-up
               (fn (thing)
                   (= z "~thing - ~z")))
     (run-hooks 'pile-it-up 1)
     (run-hooks 'pile-it-up 2)
     (run-hooks 'why-not 'a)
     (run-hooks 'pile-it-up 3)
     (run-hooks 'why-not 'b)
     (run-hooks 'why-not 'c)
     (list x y z))
   ((3 2 1) (c b a) "3 - 2 - 1 - ")))