Very cool. Hot reloading in iOS would be extreamly useful. I remember that I used a plugin that was called injectionforxcode but it was not working very well.
I have yet to find a reason to support iOS hot reloading in this context to be perfectly honest. I use the desktop bytecode hot reloading (implemented inside Reprocessing so everyone can benefit from it), and it works wonderfully well. It's faster than anything you've seen before. And given that you probably want to be coding in Reason and not objc, it doesn't really matter what your render target is while you're iterating and being creative.
I'm all ears if you can think of something though.
There is no hot reloading in the toolchain, but the compiler is very fast. I am not sure what you mean by xcode plugin, this is a js application, Reason is syntax for ocaml using bucklescript backend.
Reason code can indeed be compiled to JavaScript using the Bucklescript backend (as can regular OCaml), but it can also be compiled to native since it's just a dialect of OCaml. In the latter case, the programmer would need to avoid JS interop or employ conditional compilation.