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Re: Hack the (init) system!
From: |
Thompson, David |
Subject: |
Re: Hack the (init) system! |
Date: |
Fri, 4 Sep 2015 09:05:00 -0400 |
On Fri, Sep 4, 2015 at 8:05 AM, Ludovic Courtès <address@hidden> wrote:
> "Thompson, David" <address@hidden> skribis:
>
>> Now, I think this solves the immediate need of being able to live hack
>> dmd, but I'd like to note an additional shortcoming: Thread
>> synchronization isssues. As you know, there's potential for the main
>> dmd thread and a REPL thread to write to the same memory and blow
>> things up. In practice, this would be unlikely, but it shouldn't even
>> be a possibility. To accommodate programs that run in an event loop
>> (though I know dmd doesn't truly have this yet), Mark and I developed
>> the (system repl coop-server) module available in Guile 2.0.11. This
>> "cooperative" REPL server can be integrated into an event loop and
>> guarantee that expressions are only evaluated in the context of a
>> single thread, in this case the main thread. I think that this should
>> be the approach taken in the not-so-long term, which will require
>> modifying dmd itself.
>
> I agree that the cooperative REPL server is the way to go. I just
> couldn’t resist the temptation to hack that thing. ;-)
>
> It would be ideal if instead of having built-in support for the REPL
> server, dmd instead provided a way for services to return file
> descriptors to monitor and if they could be notified of I/O events on
> those file descriptors. That way, the REPL server could be a normal
> REPL service.
That sounds like a nice generalization.
>> Now that we can live hack dmd, we'll need some things to help make it
>> pleasant. Most of the time I am tweaking service definitions until
>> they are just right. Currently, that means calling a procedure to
>> unload the version that exists, and then registering a new one. I'd
>> like to reduce that to a single step to tighten the feedback loop.
>> What do you think about adding a 'register-services*' procedure, or
>> maybe a 'define-service' form, that first unregisters the old service
>> before registering the new one?
>
> Sounds good to me.
Okay, I will prepare some patches. Thanks.
- Dave
- Hack the (init) system!, Ludovic Courtès, 2015/09/03
- Re: Hack the (init) system!, Thompson, David, 2015/09/03
- Re: Hack the (init) system!, Thompson, David, 2015/09/03
- Re: Hack the (init) system!, Mark H Weaver, 2015/09/03
- Re: Hack the (init) system!, Ludovic Courtès, 2015/09/04
- Re: Hack the (init) system!, Andy Wingo, 2015/09/28
- Re: Hack the (init) system!, Taylan Ulrich Bayırlı/Kammer, 2015/09/29
- Re: Hack the (init) system!, Thompson, David, 2015/09/29
- Re: Hack the (init) system!, Christopher Allan Webber, 2015/09/29