Three questions

> Hi
> I have the following 3 questions:
> 1. Why there is ContextPart>>releaseTo: ? What will happen if I don't
> use it?
> 2. Is there a bytecode editor for Squeak?
> 3. Are there any issues concerning bytecode editing, contexts, closures
> and compiled methods I should be aware of, which may break the
> image/create uncollectable garbage?
>
>

> http://lists.squeakfoundation.org/mailman/listinfo/beginners
>
> I think you are on the wrong list. Try the beginners' list.
> /
> /As for the first question, why don't you just delete it and see what
> happens?
>
> Chris
>
>
> ------------------------------------------------------------------------
>
>

> On Sun, Jul 29, 2012 at 7:56 AM, Mateusz Grotek <[hidden email]>wrote:
>
>> Hi
>> I have the following 3 questions:
>> 1. Why there is ContextPart>>releaseTo: ? What will happen if I don't
>> use it?
>>
>
> releaseTo: simulates the effect of doing a method return from a block, i.e.
> when a return exits more than the top context.  It sends singleRelease to
> each context exited, which sets the pc and sender to nil (and nils the
> stack, but this is excess to requirements).  releaseTo: is actually used
> when a method return from a block encounters an unwind-protect and control
> passes up to the image to run the unwind.  You don't need to use it.  It is
> used automatically as part of running unwinds.  In what situation do you
> think you do need to use it?
>
>

> Eliot Miranda pisze:
>> On Sun, Jul 29, 2012 at 7:56 AM, Mateusz Grotek <[hidden email]>wrote:
>>
>>> Hi
>>> I have the following 3 questions:
>>> 1. Why there is ContextPart>>releaseTo: ? What will happen if I don't
>>> use it?
>>>
>>
>> releaseTo: simulates the effect of doing a method return from a block, i.e.
>> when a return exits more than the top context.  It sends singleRelease to
>> each context exited, which sets the pc and sender to nil (and nils the
>> stack, but this is excess to requirements).  releaseTo: is actually used
>> when a method return from a block encounters an unwind-protect and control
>> passes up to the image to run the unwind.  You don't need to use it.  It is
>> used automatically as part of running unwinds.  In what situation do you
>> think you do need to use it?
>>
>>
> I'm trying to implement backtracking as described in the paper:
> "Building a backtracking facility in Smalltalk without kernel support"
> by W. LaLonde and M. Van Gulik
>
> They commented their use of releaseTo: in this way:
>
> "aContext releaseTo: oldContext
> Release (by setting the temporaries in the context stack to nil) all
> contexts from the receiver, its sender, its sender's sender etc. up to
> but excluding oldContext. It is a superflous method that helps the
> garbage collector."
>
> I wondered if this is an artifact of the version of Smalltalk they used
> when writing the paper, or it really helps the garbage collector in some
> way. As far as I understand it contexts are collected just like normal
> objects, when there are no references to them. So i don't see a point in
> using this method, but I'm not an expert and maybe i miss something, so
> I asked this question.