Every entity in the game that interacts with the player is an object
an object. All objects have corresponding Lisp source files that
determines how they behave. The Lisp code can be arbitrarily complex.

Objects are not always required to have links. In general, if an object
contains has no links (that is, if no links _originate_ from that object)
then that object will start off in the active state.

B. What are Links?

Links

Links provide the means to let objects modify each other. Links also
act as the graphical method of specifying the parameters for the Lisp
code of the linking object.

Every link requres two objects. The link is originated at the object that
is to do processing (thinking). It is then attached to another object which
will act as the stimulus that determines whether or not the originating
object is active or it will act as a parameter for some type of object
manipulation.

Links are stored in a list inside the level format such that an object may
have multiple links and the order of the links is important. Facilities
exist in the editor for deleting the first or last link beloning to an
object. If the first link from an object is deleted then the remaining
links shift up by one. That is, if an object has three links and the first
is deleted then the old second link becomes the new first link and the
old third link becomes the new second link.

... Далее >>