Couldn't the language simply cache the bytecode compiled when a package runs, and only reload if the timestamp on the compiled code is older than that on the source? I believe this is what python does with its .pyc files. Then it could go a step further and cache the binary generated by compiling the bytecode to machine code... seems like there's a lot of things that could be done to speed up package loading.
This is basically what I meant. Julia doesn't really have a bytecode. There is a lower, type-inferred form of the AST as well as the llvm IR representation. However, instruction selection itself takes quite a bit of time, so if we're caching the IR, we might as well cache the generated machine code (the challenges are basically the same). As I said, it's work-in-progress (it's not that it's hard or anything, but it's a bit of work do it properly, which isn't done yet).
