Closures are the poor man's objects

I've heard this a lot without giving too much thought about it. But the Circuit Breaker made me contemplate the idea a bit. So....creating a stateful object in Clojure is actually pretty easy. The simplest I can think of is a unique id generator. This would look something like this in java

In Clojure

Of course it's a boring example so I've come up with another, slightly more interesting one, a simplified vending machine.


An epitome of applied Single Responsibility Principle. Does only one thing and hides its internals completely. Of course I could leverage dynamic typing to overload the function and perform any kind of other logic - getting information of the content, changing the state, whatever. I could make a mess, but I would have to awkwardly work against the language to do it.