# About Action List
This library implements the "action list"(link https://gamedevelopment.tutsplus.com/tutorials/the-action-list-data-structure-good-for-ui-ai-animations-and-more--gamedev-9264) data structure. This structure or paradigm is a useful alternative to state machines, and is especially suited for problems that have a temporal component.

## How To
The interface is all rather straight-forward to use, with a variety of push functions to insert actions at the appropriate places.

:: common lisp
(make-instance 'action-list:action-list)
(action-list:push-front (make-instance 'action-list:basic :update (lambda (a dt) (print dt)) :duration 1.0) *)
(dotimes (i 20)
  (action-list:update ** 0.1))
::

You can either subclass ``action`` to roll your own types, or use the ``basic`` action and supply the various parts you want to customise with closures.

If an action is ``blocking-p``, it will prevent later actions in the list from running. Without blocking actions, all actions will be updated in sequence. Blocking this from happening can be useful to ensure a sequence of actions take place.

To this end there are also the shorthand action types ``delay`` (to delay updates until a given point) and ``synchronize`` to block until all "parallel" actions before it have completed.

The ``action-list`` is also a standard ``sequence`` so you can iterate over it with ``sequences:dosequence`` and use other standard sequence operators. Note that an ``action`` instance can only be contained on a single ``action-list`` at any time. In order to copy an ``action-list``, then, each ``action`` contained needs to be copied as well. The ``copy-into`` function is used to customise this behaviour when necessary. If you create your own actions that require extra slots, make sure to properly implement ``copy-into``.