Right now, not really. PreScheme currently compiles to C. Eventually the goal is to create an assembly backend and if that were combined with incremental compilation features you could manipulate it at runtime to some degree.
The only major disadvantage is it takes time to develop.
The advantage is it makes development of the OS easier and application debugging easier. It is also makes future proofing the OS more robust. A program that can rewrite or inspect other programs is very powerful, in the same way lisp macros are.
One concrete advantage of this is you could write a debugger as a user application, it wouldn't have to be integrated in to the language runtime.
> A program that can rewrite or inspect other programs is very powerful
And is a security nightmare. If I have an executeable, I have verified, I don't want the instructions to be altered in any way. In fact I prefer if it is impossible from a hardware level by marking them as executeable bits.
This still falls within the 3L security model though. A program can only do that if you, the user, allows it.
Also, 3L runs in two modes: development or secure. In secure mode you can completely disable manipulation of source code (or strip it out) and mark all code as read only and have the system verify the code hasn't been modified when it is run.
But how is that different than what we have today? Windows for instance already does this for system files, and could be expanded to user installed files as well.
You still need a debugging build, otherwise compiler optimizations will obscure the executeable to the point where debuggers cannot reliably debug it.
