Re: continuation and multi-threading

[Michael Livshin <mlivshin at bigfoot dot com>]

Ivan Toshkov <ivant@ifao.net> writes:

> I think, the next best thing to having fast continuations is to have
> *any* continuations, which don't get much in the way of the other
> parts of the VM (is it possible?).  So, one can retain the full speed
> of the VM if that's what one needs, but olso be able to use
> continuations if that's needed.

not sure if the following is relevant, but:

* there are actually two reasons (I think) that SCM/Guile
  continuations are implemented the way they are implemented: one is
  that it's simple to implement and lets you use the implicit C stack
  as the evaluator stack; the other is that it makes continuations
  easy to manipulate from C code.

* if it's deemed nesessary to have fast continuations (and to have the 
  ability to use them to implement threads etc.), then the second
  point (ease of manupulation from C) becomes very tricky.  I guess
  it's still would be possible to support, by retaining the current
  continuation implementation but using it only when a continuation is 
  captured from C.  so you wouldn't be able to jump to such a
  continuation from another thread, and maybe there would have to be
  other limitations.

seems worth thinking about, nevertheless.

-- 
Hit the philistines three times over the head with the Elisp reference manual.
                -- Michael A. Petonic