Seems like you could do that fairly easily without making the VM 
re-entrant (whatever that might mean/entail). If you thought of your 
Squeak app and your C app as two computers on a network, they could send 
each other requests and responses all day long. No magic required.

Cheers,
Bob

On 12/3/12 10:10 AM, Blake McBride wrote:
> Greetings,
>
> I tried to integrate Squeak to a C based application more than six 
> years ago.  The project failed because we were not able to have our 
> application call Squeak, then have Squeak call the application, and 
> then the application call Squeak again recursively.  An analysis of 
> the Squeak VM revealed a kernel design consisting of a lot of global 
> variables - quite unnecessarily.  The unnecessary use of global 
> variables over a localized structure for example unnecessarily 
> prevented the use of Squeak as an extension language (unless you had 
> no recursion).  I spent several days trying to re-structure the Squeak 
> kernel but I kept running into problems and just ran out of time.
>
> As a side note, that company I was with ended up making a lot of 
> investment in Scheme because we were easily able to integrate that 
> language with our application.  Now, not only is Scheme used heavily 
> within that company but many of their clients use it too to customize 
> their application.
>
> This brings me to my question, is COG reentrant?  If not, as the 
> author of COG, I would think it relatively easy to restructure it to 
> be so.  Such a design capability can make a huge difference to COG's 
> acceptance to many.  It may even be the reason to switch to COG.
>
> Just sharing some thoughts.  Thanks.
>
> Blake McBride
>
> On Sun, Dec 2, 2012 at 7:55 PM, Eliot Miranda <eliot.miranda at gmail.com 
> <mailto:eliot.miranda at gmail.com>> wrote:
>
>     ...in http://www.mirandabanda.org/files/Cog/VM/VM.r2628
>     <http://www.mirandabanda.org/files/Cog/VM/VM.r2628>.
>
>     These fix a bug with pc mapping that could cause the Vm to crash
>     on simple loops containing arithmetic on constants (e.g. 1 to: 20
>     do: [:i| 1=1]).  They also cause the instantiation primitives to
>     pop all their arguments rather than assume their argument count is
>     0 or 1.  More change info available in the directory.
>     -- 
>     best,
>     Eliot
>
>
>
>
>
>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.squeakfoundation.org/pipermail/squeak-dev/attachments/20121203/c95727f4/attachment.htm