[x/Programs] Simulator Architecture Research about hypersdk

[richardpringle]

How would state across multiple simulator calls be stored?

@dboehm-avalabs and I chatted about this a bit. You should be able to have a State struct that implements all the interfaces (mutable, view, etc) that is simply instantiated with a few function pointers. Those function pointers can come from the Rust side of the simulator. I'm pretty sure you can even use a function pointer to a closure, though how to do so soundly is less clear.

In any case, you should essentially be able to inject the state-dependency on instantiation of the cgo wrapper around the runtime.

Does that make sense?

[richardpringle]

gRPC

Should note that shared types are defined in protobufs. You would still need to spin up the server via Rust, but that should almost be trivial.

[samliok]

@dboehm-avalabs and I chatted about this a bit. You should be able to have a State struct that implements all the interfaces (mutable, view, etc) that is simply instantiated with a few function pointers. Those function pointers can come from the Rust side of the simulator. I'm pretty sure you can even use a function pointer to a closure, though how to do so soundly is less clear.

so essentially you pass in the struct with method pointers through FFI, and then in go you reconstruct that interface by referencing those function pointers.