Scheme is cleaner than common lisp. I think Gambit-C has an implementation of Erlang's message passing and mailbox idea for each process and in addition to that

Scheme is cleaner than common lisp. I think Gambit-C has an implementation of Erlang's message passing and mailbox idea for each process and in addition to that it doesn't use OS threads for individual processes it uses first class continuations. In one test it performed similar to Erlang running as many as 900K processes on a 1GB ram P4. http://people.csail.mit.edu/gregs/ll1-discuss-archive-html/msg03309.html http://people.csail.mit.edu/gregs/ll1-discuss-archive-html/msg03309.html Having said this. I'm really interested in Erlang because of mnesia. I'm not sure if I want to spend a bit of my life writing a database in Gambit. Here are thoughts from someone who choose Erlang over Scheme. http://theschemeway.blogspot.com/ http://theschemeway.blogspot.com/ I don't really agree with his point of view. I think if your problem doesn't really have a strong concurrency element in it which you would solve by using shared data then it probably doesn't make sense to use the message passing model. Having said that if you are writing for the web one day it definitely will have a strong need for concurrency.