Seven Concurrency Models in Seven Weeks

Wrap-Up

On the surface, actor and CSP programs are very similar—both are constructed from independent, concurrently executing tasks that communicate by sending each other messages. But as we’ve seen in this chapter, their different emphases result in very different flavors.

Strengths

The primary strength of CSP compared to actors is flexibility. In an actor program, the medium of communication is tightly coupled to the unit of execution—each actor has precisely one mailbox. In a CSP program, by contrast, channels are first class and can be independently created, written to, read from, and passed between tasks.

Rich Hickey, creator of the Clojure language, explained his reasons for choosing CSP over actors like this:^[42]

I remain unenthusiastic ...