[rocqua]

The function system doesn't hold 'global' state. It holds the state in arguments given to functions. If you want a client, you still have a bit of client 'data' and you pass that around your functions.

If you wanna do stuff to the client, you call functions with the client as an argument. If you want polymorphic clients, you define a client typeclass / trait / interface called Client, and then your functions take a generic Client bit of data.

In some sense, this approach is a lot like replacing foo.bar() with foo(bar). Which doesn't do much to change your program. The interesting difference in FP is how you 'change the state' of your client.

In FP, if you want your client to e.g. count its connections you would do something like `nextClient = connect(oldClient)` instead of the OOP `client.connect()`. This means that you are a lot more explicit about your state changes. This has a lot of advantages that can be hard to wrap your head around. It also comes with some disadvantages.

As a result though, all of your state is carried very 'locally' in your functions scopes.