Re: First-class continuations in Kawa

[Duncan Mak <duncanmak@gmail.com>]

Hello Per,

https://gitlab.com/kashell/Kawa/merge_requests/22 should be ready for
review now.

You mentioned in your first reply that we should "test, evaluate, and
benchmark it. If it's useful, it should be merged in." - do you have
any suggestions for how I should proceed to get this merged in?

You also mentioned that there's an idea on an alternative
implementation technique based on switch statements - could we post
the notes on https://gitlab.com/kashell/Kawa/issues, and perhaps
someone else could tackle that?


Duncan.

On Tue, Feb 20, 2018 at 7:21 PM, Andrea Bernardini <andrebask@gmail.com> wrote:
> Hi All,
> Regarding delimited continuations, you can see the needed changes here
> https://gitlab.com/andrebask/Kawa/compare/callcc...delimited-continuations
>
> Let me know if you are interested in this at all, shouldn't be
> difficult to add this once Duncan's pull request is merged in.
>
> In the same fork there's also a branch with the debugger
> implementation, however I'm not sure how useful that could be, it was
> quite experimental
>
> Thanks,
> Andrea
>
> On 20 January 2018 at 23:20, Andrea Bernardini <andrebask@gmail.com> wrote:
>> Yep, that's it. The whole work was originally submitted as patch.
>>
>> It is also my fault If this was never merged into master. I remember
>> that I started working on a switch-based variant of my work after
>> getting some high level suggestions from Per. That turned out to be a
>> fair amount of work and I didn't have much time, so I didn't manage to
>> put together anything working.
>>
>> I also have some working code that I mentioned in my thesis but didn't
>> end up in that patch, as it wasn't well tested. This was mainly for
>> delimited continuations and for the debugger. I'll share this soon in
>> a GitLab fork so it doesn't get lost.
>>
>> Andrea
>>
>> On 20 January 2018 at 16:06, Duncan Mak <duncanmak@gmail.com> wrote:
>>> Looks interesting.
>>>
>>> Is the work contained in only these two commits?
>>>
>>> https://gitlab.com/kashell/Kawa/commit/a8e678ebf7216e9fad9238e0b1c2442ea371c63c
>>> https://gitlab.com/kashell/Kawa/commit/f4228b57936de5a84dba0afcfac54196bec86fa4
>>>
>>>
>>> Duncan.
>>>
>>>
>>> On Sat, Jan 20, 2018 at 1:46 AM, Per Bothner <per@bothner.com> wrote:
>>>> On 01/19/2018 04:48 PM, Duncan Mak wrote:
>>>>>
>>>>> Hello,
>>>>>
>>>>> I came across Andrea Bernardini's thesis called First-Class
>>>>> Continuations on the Java Virtual Machine: An Implementation within
>>>>> the Kawa Scheme Compiler just the other day.
>>>>>
>>>>>
>>>>> https://www.politesi.polimi.it/bitstream/10589/108685/3/2015_07_Bernardini.pdf
>>>>>
>>>>> What happened to that work, was it integrated into the mainline release of
>>>>> Kawa?
>>>>
>>>>
>>>> Sorry, no. Andrea's work is available in the 'callcc' branch, but it has not
>>>> been merged into master.  Worse, updates to master have not been merged
>>>> into the callcc branch.
>>>>
>>>> It would be useful to at least update the callcc branch with recent changes,
>>>> and then test, evaluate, and benchmark it. If it is useful, it should be
>>>> merged in.
>>>> Even if it is slow, as long as it doesn't hurt the default behavior.  It is
>>>> my fault
>>>> that hasn't been done, but there were always other things to do.
>>>>
>>>> Long time ago, I started on another implementation of continuations based on
>>>> switch statements.  (Each continuation point would be associated with an
>>>> index,
>>>> and each function would start with a switch statement with jumps to the
>>>> continuation points. Capturing a continuation would essentially be saving
>>>> the
>>>> corresponding switch index.)  Some of that code is still in Kawa, but
>>>> commented out.  Following up on that idea might be more efficient.  Which
>>>> isn't really a good excuse for not merging in Andrea's work.
>>>>
>>>> If someone is interested in following up on this work, that would be great.
>>>> --
>>>>         --Per Bothner
>>>> per@bothner.com   http://per.bothner.com/
>>>
>>>
>>>
>>> --
>>> Duncan.



-- 
Duncan.