This is a simple and easy to use Actor system in Common Lisp. ****** Set-Up ************ 1. Requires Bordeaux threads. http://common-lisp.net/project/bordeaux-threads/ 2. Just load actors.lisp and start using it. ****** Usage ************ An small manual can be found at : http://www.cs.rpi.edu/~govinn/actors.pdf 1. Creating an actor class or template (defactor Actor-Class (state) (message-vars) behavior) 2. Creating an actor instance (setq my-actor (Actor-Class (:state-var_1 value_1 ... :state-var_n value_n))) 3. Sending a message (send my-actor message_args) ****** Features ************ 1. Concurrency using the actors model. 2. Dynamic behavior change of actors. ****** Examples ************ 1. A ticker: Keeps printing out a count every 2 seconds, starting from 0 and incrementing it every 2 seconds. ;create the ticker template (defactor ticker ((counter 0)) (m) (sleep 2) (pr counter) (incf counter) (send self nil) next) ; Create an instance (setf t1 (ticker)) ; send a message (async) (send t1 nil) ; to stop use (stop-actor t1) 2. A print actor: Prints the message which was sent to it. A very useful utility actor. ;create the actor template (defactor print-actor () (val) (pr val) next) ; initialize a new instance (setf printer (print-actor)) ;send values for printing (send printer "hello, world") 3. A factorial computing actor : The name says it all :) ;create the template (defactor fact ((temp 1)) (n cust) (if (equal 1 n) (progn (send cust (* temp 1)) (setf temp 1) next) (progn (setf temp (* n temp)) (send self (- n 1) cust) next))) ;create a new instance (setf f (fact)) ; send a value (send f 4 print-actor) 4. A nagger for fun : Works only in Mac OS X. Keeps saying out aloud "please work" every 10 seconds :) (defactor nagger () () (sleep 10) (trivial-shell:shell-command "say please work") (send self) next) ; anonymous actor , no way to stop the nagging (send (nagger))