> Wouldn't it be OK if the initial focus was something else and then there was a change of focus?
Retrofitting features into existing languages is rarely satisfying in my experience.
Sure, Python now has functional constructs, but variables are still mutable, so bizarre things can happen inside a map call.
In Erlang, immutability is baked into everything.
Message passing can be added as a library, but you don’t get the same impact as everything being a message. Does your random 3rd party library also use messages? Probably not.
Erlang is a very opinionated language and runtime with a small set of core concepts, and it is very predictable as a consequence.
Java or C++ have just about any feature you can think of, which is beneficial in some ways, but they’re also much more complex.
And why does from the get-go on parallel matter? Wouldn't it be OK if the initial focus was something else and then there was a change of focus?
And processes as first class depends what you mean: https://live.exept.de/doc/online/english/overview/basicClass...
And hot code swapping: Smalltalk.