Sat, 10 May 1997 05:14:02 -0400 (EDT)
> I hesitated to bring this up here. I feel it will probably get shot down
> pretty thoroughly. How about ANSI Forth (with much extension) as the low
> level core (and ultimately the implementation language for whatever Lisp
> is chosen, until the Lisp compiles itself and we can throw away that
I'm not familiar with forth, but from what I've heard it is a
good choice for extremely low level code, and from memory it probably
has the reflective properties we need, without lots of overhead.
> - Many of today's machines (Sparcs, PowerPCs, some PCI-bus machines)
> come with a full ANSI Forth core in the OpenBoot Firmware. There
> will be for these machines complete low level diagnostics and some
> primitive kind of device driver available for all supported
> devices. Those machines without OpenBoot Firmware could be made
> to quickly load an ANSI Forth core.
This is an excellent point. :) Device drivers are a bastard to write.
> - Forth is well known to port very easily and runs in all kinds of
> environments. If the LispVM were implemented in Forth then we
> could quickly bring it up under various OS's, standalone, have
> real-time subset implementations for embedded distributed
> applications, etc. etc. A portable Forth like GForth (GNU)
> could be used for initial ports. One report I read recently was that
> 2 guys brought up GForth in a new embedded environment on a
> new machine architecture in a weekend. Now, they feel with the
> work they did to simplify the porting, it could be done in an
> - Mop systems have been implemented in Forth and seem to work quite well.
> Reflection seems possible, but I don't know of any practice along these
This could be the only real sticking point.
> - Including threading support might be tricky in any portable way.
I can't think of any portable threading systems, but it should be
relatively easy, this is where people want to think if they want
a continuation passing style system, or one with chunky stacks.
> - Forth scales poorly, but I do propose getting to a Lisp language
> fairly quickly.
Yeah, it would be interesting to see a toy lisp-over-forth system.
There may be one already around, I'll have a look over the web.
but I think its a great idea, and if you haven't hit the nail on the head
you're not far off.