[anonymousDan]

So would I be right in saying that to update a function from v1 to v2, in a statically typed language I can't change the function prototype, whereas with a dynamically typed language I can? Would I not still be somewhat limited in the latter case (e.g. I'd have to have the same number of arguments)?

[alavrik]

I think you can do both in static and dynamic languages, but in dynamic language everything is just practically easier.

Another thing I forgot to mention, and it is more important than my first example, -- in Erlang, during the upgrade procedure, you can have two versions of the same module loaded simultaneously and their code can execute at the same time until all the code starts using functions from the second module. Basically, when you call a function, you can specify explicitly to call it the current module or from the new module. I can hardly imagine how you can get away with it in statically-typed language.

If you are interested in the topic I recommend reading Joe Armstrong's PhD thesis. It describes this and many other advanced topics in detail. Actually, it changed the way I think about concurrent and fault-tolerant systems and languages.