Learn You Some Erlang: What is OTP & Clients and Servers
learnyousomeerlang.com
learnyousomeerlang.com
It's nicely written and light enough as well, nothing too heavy.
-export(start_link/0, order_cat/4, return_cat/1, close_shop/1]).
Is seems odd to me that the close bracket is just dangling at the end. I find the Erlang syntax rather inscrutable...Prolog's syntax is a lot cleaner, though - if you took your favorite language and added lots of new operators, so they were clearly the new language, how would it turn out? A lot of minor issues with Erlang (e.g. the whole ; vs , vs . thing) come from that.
Once you get past the surface details, though, Erlang kicks ass. Hold on!
(Prolog is awesome, too.)