actors4clj

Extremely simple actors library for Clojure.

This library implements "classic" (or "Agha-style") actors for Clojure, using macro's. It is extremely simple (fewer than 100 lines of code), with the goal of being easy to extend and experiment with.

Usage

There are five constructs:

• (behavior [x ...] [pattern] (response) ...) defines a behavior, which specifies how an actor should respond to incoming messages.
• (spawn beh [v ...]) spawns a new actor with the given behavior and internal state.
• (send actor1 v ...) asynchronously sends a message to an actor.
• (become beh [v ...]) updates the current actor's behavior and internal state.
• self is a global variable that always refers to the current actor.

Example:

(def counter
  (behavior [i]
    [:get]
      (println "count:" i)
    [:inc]
      (do
        (println "count:" i "+ 1")
        (become :self [(+ i 1)]))
    [:add j]
      (do
        (println "count:" i "+" j)
        (become :self [(+ i j)]))))

(def counter1 (spawn counter [0]))
(send counter1 :inc)
(send counter1 :add 5)
(send counter1 :get)   ; => 6
(send counter1 :add 4)
(send counter1 :get)   ; => 10

A behavior contains:

• a list of parameters, which form its "internal state".
• a list of patterns and corresponding code blocks. Incoming messages are compared to the patterns (using core.match), and the code corresponding with the first match is executed.

License

Licensed under the MIT license, included in the file LICENSE.