This example illustrates "typical" use of action lists. The define-action forms might be scattered across several files (
mail-utilities.lisp
,
caffeine.lisp
, and so on). Each of the functions, such as
read-mail
,
dont-panic
, and so on, take one argument:
hassled-p
.
(in-package "CL-USER")
(define-action-list "On arrival at office"
:documentation "Things to do in the morning"
:dummy-actions '("Look busy")
:default-order '(:before "Look busy"))
(define-action "On arrival at office" "Read mail" 'read-mail)
(define-action "On arrival at office" "Greet co-workers"
'say-hello)
(define-action "On arrival at office" "Drink much coffee"
'wake-up:after "Locate coffee machine")
(define-action "On arrival at office" "Locate coffee machine"
'dont-panic)
(defun my-morning (hassled-p Monday-p)
(execute-actions ("On arrival at office"
:ignore-errors-p Monday-p)
hassled-p)
<rest of my-morning code goes here >)
This example illustrates use of execution-functions and post-processing
(in-package "CL-USER")
Here are the implementation details, which are hidden from the "user".
(defstruct (thing (:constructor make-thing (name number)))
name
number)
(defvar *things*
(make-unregistered-action-list :sort-time :define-action
:execution-function 'act-on-things))
(defun do-things (function &optional post-process)
(execute-actions (*things* :post-process post-process)
function))
(defun act-on-things (things other-args-list &key post-process)
(with-action-list-mapping
(things ignore thing post-process)
(destructuring-bind
(function) other-args-list
(funcall function thing))))
The interface is given below. The internals of the mapping mechanism are hidden.
(defmacro define-thing (name number)
(with-unique-names (thing)
`(let ((,thing (make-thing ,name ,number)))
(define-action *things* ',name ,thing))))
(defmacro undefine-thing (name)
`(undefine-action *things* ,name))
(defun find-thing (name)
(do-things #'(lambda (thing)
(and (equal name (thing-name thing))
thing))
:or))
(defun add-things ()
(reduce '+ (do-things 'thing-number :collect)))