What's the spec for emacs lisp virtual machine ?

What's the spec for emacs lisp virtual machine ?

[Fren Zeee]

What's the spec for emacs lisp virtual machine ?

Where are the complete set of virtual machine commands ?

Where is the theory for such a virtual machine in the clearest
description ? (not general theory, but one applicable directly to
understanding emacs vm.)

Does the emacs lisp operate as a stack push/pop or as parsing ?

Why is a VM needed when there is compiled C code running machine code ?

How do you implement a LISP interpreter using a stack based and syntax
tree methods ?

Some overview with concrete examples please, but of practical value.

Also, for either you need a scanner and so an example of a scanner
using a transition table. How do you decide on the states that are
minimal and not redundant ?

What is the difference between a stack architecture of a processor and
register based one ? wouldnt the former still need an ALU and indirect
addressing to do the job ? A diagram and some explanation, or else we
will be in the domain of linguistic ambiguity.

Upload a hand sketched image if necessary, or a reference to specific
pages in google books.

I have done searches on wiki and other places but the things are not
entirely clear because they are not oriented to my goal of centering
around emacs.

Thanks
Franz Xe

Re: What's the spec for emacs lisp virtual machine ?

[Alfred M. Szmidt]

   I have done searches on wiki and other places but the things are not
   entirely clear because they are not oriented to my goal of centering
   around emacs.

Have you tried looking at the source code for emacs?  It isn't that
complex and the code is well commented, it is also the best place for
any details regarding emacs.  The VM is located in emacs/src/eval.c,
the byte-code compiler in emacs/lisp/emacs-lisp/bytecomp.el.  You can
use the disassemble function to disassemble emacs byte-code.

Re: What's the spec for emacs lisp virtual machine ?

[Thien-Thi Nguyen]

() Fren Zeee <frenzeee@gmail.com>
() Thu, 22 Jul 2010 23:15:17 -0700

   What's the spec for emacs lisp virtual machine ?

   [and other design questions]

I suggest you start a page on the Emacs wiki, and place these questions there.
This will more likely result in better responses and discussion than a thread
on this mailing list.

Re: What's the spec for emacs lisp virtual machine ?

[Fren Zeee]

On Fri, Jul 23, 2010 at 12:28 AM, Alfred M. Szmidt <ams@gnu.org> wrote:
>   I have done searches on wiki and other places but the things are not
>   entirely clear because they are not oriented to my goal of centering
>   around emacs.
>
> Have you tried looking at the source code for emacs?  It isn't that
> complex and the code is well commented, it is also the best place for
> any details regarding emacs.  The VM is located in emacs/src/eval.c,
> the byte-code compiler in emacs/lisp/emacs-lisp/bytecomp.el.  You can
> use the disassemble function to disassemble emacs byte-code.
>

I have looked at some header and C files on the savannah site, not this one.

I am waiting for a reply from the group and RMS on the earliest
sources which were probably smaller also, like 13 to 16.56 which might
be simpler for this newbie.

Perhaps, you may put a snippet to actually show a few things to this newbie.

I think often its best to demonstrate then to direct particularly for
those who say its easy for them.

What type of scanner does the Lisp parser and interpreter use ? Is it
listed ? Is there a FSM state transition table drawn ?

Franz Xe

Re: What's the spec for emacs lisp virtual machine ?

[Chong Yidong]

Fren Zeee <frenzeee@gmail.com> writes:

> I have looked at some header and C files on the savannah site, not this one.
>
> I am waiting for a reply from the group and RMS on the earliest
> sources which were probably smaller also, like 13 to 16.56 which might
> be simpler for this newbie.
>
> What type of scanner does the Lisp parser and interpreter use ? Is it
> listed ? Is there a FSM state transition table drawn ?

From Emacs, do

  `C-h f read'
  `C-h f eval'

and follow the sources.  I don't think it's profitable to look at early
versions of Emacs; that's a wild goose chase.  The fact that the sources
are bigger now than in earlier versions is irrelevant, if you're only
going to be looking at the Lisp reader and interpreter.