[Yhc] some initial questions

[Neil Mitchell]

Hi Robert

> 1) I'm interested in the possibility of doing Java-style verification of
> bytecode, so I've been studying the bytecode docs.  Looking at the bytecodes,
> I notice that all the jump bytecodes seem to indicate that jumps are always
> forward jumps.  Upon reflection it makes perfect sense, but I want to make
> sure that is a conscious design decision.  It certainly makes the kinds of
> analysis I'm interested in easier...

Yes, it is a concious decision, since only forward jumps are required.
>From what I know (and I may be wrong here), adding backward jumps
would have little impact on the execution of the bytecode, but just
isn't needed.

A byte code verifier would be cool :)


> 2) I notice that concurrency is a big unclaimed todo item.  Are there any
> concrete plans in this direction?  I'm sort of interested in this, but before
> I think about it too much, I was wondering what has and has not been thought
> about/done so far.

Tom has a working implementation of concurrency on his machine, and is
just doing a bit of testing before committing. It isn't OS/machine
level concurrency (it just switches thread every n instructions), but
it has been implemented including MVar's.

Thanks

Neil