Re: Reviving Guile-VM

[Ludovic Courtès]

Hello,

Neil Jerram <address@hidden> writes:

> That is excellent news.  It always seemed like a very interesting
> project when Keisuke was working on it and discussing on the mailing
> list.  (Unfortunately, though, I can't say that I understood it very
> much.)

Well, it seems that it had became quite ambitious in the end.

> One point of possible interest is that at about that time, qscheme was
> also donated to the CVS repo, and my impression was that qscheme also
> contained some kind of VM technology.  It might be worth you taking a
> look at qscheme also, therefore.

QScheme [1] has apparently been abandoned since 2000, and it looks like
its VM has never been fully functional.  Guile-VM seems much more mature
actually.  However, that of STklos is fully functional and it seems to
be pretty close to Guile-VM (similar instruction set).

> Hang on, I thought the instructions were byte code ...  How many
> levels of byte code are there, and how do they differ?

Bytecode is just the binary representation of a sequence of
instructions, no more.

However, the compiler does use _two_ intermediate languages when
compiling Scheme to VM "assembly":

  Scheme -> GHIL -> GLIL -> assembly

(where GHIL stands for "Guile's High-level Intermediate Language" and
GLIL stands for "Guile's Low-level Intermediate Language").  The former
is pretty close to Scheme while the latter is closer to the VM's
assembly.  I think the goal was to make Guile-VM easily usable for other
languages as well.  Fun.  ;-)

Thanks,
Ludovic.


[1] http://sof.ch/dan/qscheme/index-e.html