[Vm-dev] Re: [squeak-dev] New Cog VMs available
Blake McBride
blake at mcbride.name
Mon Dec 3 19:39:51 UTC 2012
Hello Eliot,
On Mon, Dec 3, 2012 at 1:09 PM, Eliot Miranda <eliot.miranda at gmail.com>wrote:
>
> Hi Blake,
>
> On Mon, Dec 3, 2012 at 7:10 AM, Blake McBride <blake at mcbride.name> 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?
>>
>
> Yes it is. It supports call-outs and call-ins. But currently there is no
> support for Cog to be packaged as a DLL. You have to start by calling C
> from Squeak.
>
I believe the regular Squeak supports call-outs and call-ins as well. The
real question is if it can be done recursively.
Can you initialize a new instance of the VM in the middle of a nested
call-in / callout?
Can an instance be cloned? Destroyed?
Thanks.
Blake
>
>
>
>
>> 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.
>>
>
> Yes indeed. The issue is of course funding to spend the time to make the
> necessary changes.
>
>
>> Just sharing some thoughts. Thanks.
>>
>> Blake McBride
>>
>> On Sun, Dec 2, 2012 at 7:55 PM, Eliot Miranda <eliot.miranda at gmail.com>wrote:
>>
>>> ...in 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
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>
>
> --
> best,
> Eliot
>
>
>
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