Could modern programming languages adopt isolated heaps with message passing like Erlang does? This is the easiest solution to GC pauses and allows other nice features like hot code reloading.
The majority of programming languages invented in the last 10 years don't seem that different from each other. I'd love to see a programming language that combines the strength of C++ and Erlang for soft realtime workloads.
From _The Beam Book_:
> There are two types of integers in ERTS, small integers and bignums. Small integers fits in one machine word minus four tag bits, i.e. in 28 or 60 bits for 32 and 64 bits system respectively. Bignums on the other hand can be as large as needed (only limited by the heap space) and are stored on the heap, as boxed objects.
Outside of that, I have found Elixir/Erlang to be very resource efficient. And if you need blazing fast math, you can always implement such computations in C and expose it in your Elixir/Erlang application using NIFs. There are a few golden rules to pay attention to in order to avoid danger, but if you do, you can get great speed. I'm currently implementing a Protocol Buffer library in Elixir and expect to make use of this for increased performance once my library is feature complete(if I find performance to be an issue at scale).
Im going to do some C++
Im going to do some Java
Im going to do some Pony
I've done some experimentation with hot reloading in c lately, and I'm not sure how isolated heaps is a precondition for code reloading.
I suspect the requirement for erlang style code reloading is a willingness to take an indirection penalty for fully qualified module calls and tail call optimization so that the old module doesn't stay in process stacks. In an OOP language, if you wanted to tie objects to specific versions of modules, you'd have to do some intrusive accounting as well.
I also attempted hot code reloading in perl many years ago; it's a lot easier to do when you've seen it done properly, and there are language facilities for it (fdlopen is a lot nicer to use than exec on a pm). In my use cases (which were single threaded), I was able to write an outside loop that's simple enough that it's not a big deal that it can't be reloaded.