Are you talking about Clojure? :)
I am not sure what is the fuss about functional vs. imperative, you can do both in Clojure, both ways have a place in the programming toolkit. I think about functional programming as a philosophy. Nobody is going to despite me if I use swap! in Clojure or I use a mutable variable. On the other hand even when I am in an imperative environment I tend to use functions that keep the state in the parameters so the state is explicit and visible rather than a hidden something inside a class.
Yes Clojure, sorry about the typo! The difference is that with Haskell or Erlang you get hard guarantees about side effects, but access to imperative libraries is very difficult. So you are kind of locked in a small ecosystem.
With Clojure, Scala or F# you need to be disciplined and don't really get many guarantees, but you can reuse lots of imperative code.
It kind of depends what your priorities are, if it's correctness or development speed.
> The difference is that with Haskell or Erlang you get hard
> guarantees about side effects, but access to imperative
> libraries is very difficult.
Well yes, I can just live without imperative libraries because it is so natural to have single assignment (in the same scope) that I do it even in other languages. Accessing imperative libraries is possible though, just think about the C libs. What would you implement in Erlang the imperative way or which library do you miss exactly? The ecosystem is definitely smaller, but you can get support, some of the smartest software guys hang out on the mailing lists and IRc as well. I got absolutely amazing help from both when we worked on a Erlang project.
> It kind of depends what your priorities are, if
> it's correctness or development speed.
Yeah and also how much fun you want to have. :)
Using Erlang is great but not many devs out there for hire, on the other side you have two seasoned Erlang devs they can do a lot. Contractors FTW!
Btw. what about using ASN.1 with Erlang? How does that change the correctness / development speed?
> The difference is that with Haskell or Erlang you get hard guarantees about side effects, but access to imperative libraries is very difficult.
In my experience creating Haskell bindings to say imperative c libraries is pretty easy. What imperative libraries have been hard to access for you personally?
> The difference is that with Haskell or Erlang you get hard guarantees about side effects
As far as I know Erlang doesn't give you any guarantees about side effects. You can call side-effecting functions at any point in your program, just like in Clojure or OCaml.
