simple-actors

The actor model implemented with closures.

Creating an actor

CL-USER> (defvar *result* nil)
*RESULT*
CL-USER> (defparameter *actor* (simple-actors:actor (&rest numbers)
				  (setf *result*
					(loop for n in numbers
					   collect (* n 2)))))
*ACTOR*
CL-USER> *actor*
#<SIMPLE-ACTORS:ACTOR {10069D2963}>

Actors can be sent messages that match their lambda-list. These messages go into a queue, and the actor's body is evaluated with each message in order:

CL-USER> (simple-actors:send *actor* 1 2 3 4 5 6)
NIL
CL-USER> *result*
(2 4 6 8 10 12)

Each actor has a thread associated with it:

CL-USER> (bt:all-threads)
(#<SB-THREAD:THREAD "Actor" RUNNING {1006919D53}>
 #<SB-THREAD:THREAD "finalizer" RUNNING {1001B80053}>
 #<SB-THREAD:THREAD "repl-thread" RUNNING {100250FF93}>
 #<SB-THREAD:THREAD "auto-flush-thread" RUNNING {100250FDA3}>
 #<SB-THREAD:THREAD "swank-indentation-cache-thread" RUNNING {1004458183}>
 #<SB-THREAD:THREAD "reader-thread" RUNNING {1004458083}>
 #<SB-THREAD:THREAD "control-thread" RUNNING {1004450D73}>
 #<SB-THREAD:THREAD "Swank Sentinel" RUNNING {1004164873}>
 #<SB-THREAD:THREAD "main thread" RUNNING {10005E8203}>)

The actor's thread terminates when it is sent the simple-actors:stop message. This message is not passed to the actor's body.

CL-USER> (simple-actors:send *actor* 'simple-actors:stop)
NIL
CL-USER> (bt:all-threads)
(#<SB-THREAD:THREAD "finalizer" RUNNING {1001B80053}>
 #<SB-THREAD:THREAD "repl-thread" RUNNING {100250FF93}>
 #<SB-THREAD:THREAD "auto-flush-thread" RUNNING {100250FDA3}>
 #<SB-THREAD:THREAD "swank-indentation-cache-thread" RUNNING {1004458183}>
 #<SB-THREAD:THREAD "reader-thread" RUNNING {1004458083}>
 #<SB-THREAD:THREAD "control-thread" RUNNING {1004450D73}>
 #<SB-THREAD:THREAD "Swank Sentinel" RUNNING {1004164873}>
 #<SB-THREAD:THREAD "main thread" RUNNING {10005E8203}>)