(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 - ")))