Re: GNU Guile branch, master, updated. v2.1.0-163-g283ab48

Re: GNU Guile branch, master, updated. v2.1.0-163-g283ab48

[Mark H Weaver]

Hi Andy,

> commit 283ab48d3f20a5c5281cafc29f0c30c8d8ace9ee
> Author: Andy Wingo <wingo-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
> Date:   Wed Mar 7 19:01:56 2012 +0100
>
>     faster (make-prompt-tag); default-prompt-tag is a parameter
>     
>     * module/ice-9/boot-9.scm (default-prompt-tag): Once parameters have
>       booted, redefine as a parameter.

I fear that making 'default-prompt-tag' a parameter might slow things
down quite a bit on platforms with a slow implementation of thread local
storage.

What's the anticipated use case for this?

     Thanks,
       Mark

Re: GNU Guile branch, master, updated. v2.1.0-163-g283ab48

[Andy Wingo]

Hi,

On Thu 08 Mar 2012 03:29, Mark H Weaver <mhw@netris.org> writes:

>> commit 283ab48d3f20a5c5281cafc29f0c30c8d8ace9ee
>> Author: Andy Wingo <wingo-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
>> Date:   Wed Mar 7 19:01:56 2012 +0100
>>
>>     faster (make-prompt-tag); default-prompt-tag is a parameter
>>     
>>     * module/ice-9/boot-9.scm (default-prompt-tag): Once parameters have
>>       booted, redefine as a parameter.
>
> I fear that making 'default-prompt-tag' a parameter might slow things
> down quite a bit on platforms with a slow implementation of thread local
> storage.

Not the case!  It shouldn't depend on thread-local storage at all
actually since the VM already has a handle on the current thread and
dynamic state.

> What's the anticipated use case for this?

Parameterizing default prompts?  It allows users to re-set the
user/system process boundary for a dynamic extent.

Andy
-- 
http://wingolog.org/

Re: GNU Guile branch, master, updated. v2.1.0-163-g283ab48

[Mark H Weaver]

Andy Wingo <wingo@pobox.com> writes:

>> I fear that making 'default-prompt-tag' a parameter might slow things
>> down quite a bit on platforms with a slow implementation of thread local
>> storage.
>
> Not the case!  It shouldn't depend on thread-local storage at all
> actually since the VM already has a handle on the current thread and
> dynamic state.

Ah yes, indeed that is true.

>> What's the anticipated use case for this?
>
> Parameterizing default prompts?  It allows users to re-set the
> user/system process boundary for a dynamic extent.

Okay, makes sense.  Sorry for the bother.

   Thanks!
     Mark

Re: GNU Guile branch, master, updated. v2.1.0-163-g283ab48

[Andy Wingo]

On Thu 08 Mar 2012 15:28, Mark H Weaver <mhw@netris.org> writes:

>>> What's the anticipated use case for this?
>>
>> Parameterizing default prompts?  It allows users to re-set the
>> user/system process boundary for a dynamic extent.
>
> Okay, makes sense.  Sorry for the bother.

No problem.  I don't have a deep understanding of how default prompts
can / should be used.  Something that needs some experience, I think.

Regards,

Andy
-- 
http://wingolog.org/