Hello, I am considering using rpython to optimize some interpreter like code and I have a few questions that I couldn't quite figure out from pypy's source. 1. Is it possible to call something written in rpython from "normal python" (either running on cPython or PyPy)?  Ideally, I would like something where objects could be shared between the two environments.  Can I compile something using rpython and then turn that into a C compiled python module that can share objects with the interpreter. 2. How much control can I have over the tracing compiler, eg is it possible to forcing something to be traced the first time it is run? 3. If I am inside of a trace, can I add my own guards or conditionally aborting trace and returning to an interpreted version of the code.   I am going to have some code like:       if self.method is None:           # this branch is only taken at most once for this object           # Abort the trace???           self.method = build_method()  # marked as an elidable method?     self.method(....)     4. How can I use threads from inside rpython?  What considerations do I need to make when interacting with the JitDriver.  What sorts of atomic operations are available when interfacing with my data structures.  What considerations would I need to make to work with rpython's GC.  Can I release "normal python's" GIL when writing threaded code from rpython?    Also, is software transactional memory usable by things that are not PyPy?  It looks like there where a few branches that haven't been merged. 5. Inside of a trace, I would like to be able to look at mutable objects (namely the entire current stack frame) from an elidable methods and have the result be cached without a need for any guards.  This is something that I know will be safe due to how the program was written, but not something I would expect rpython to be able to deduce from the context of a trace.  How can I annotate a method to be able to do this? Thanks, Matthew -- Matthew Francis-Landau