Re: [Chicken-users] egg announcement: remote-repl

[Alaric Snell-Pym]

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On 19 Aug 2008, at 10:27 am, Jörg F. Wittenberger wrote:

> That's what I have been able to do bevor.  That's not the aim.  I need
> to change all timeouts for all thread which are started after the
> change.

This boils down to an interesting question: if you have some values  
that generally follow the 'design pattern' of a parameter - with  
dynamically-scoped thread-local overrides and all that - how do you  
tweak it from outside the thread?

I think this is only a legitimate thing to do in debugging; if you  
want to do that as part of your normal use of the app, then using  
parameters in the first place was a mistake!

Normal production configuration changes should probably be handled in  
a server system by instructing the master thread to set new values  
into its parameters, which *new session threads* would then inherit  
from it, so that existing session threads keep the old values -  
unless you want to audit your code for the consequences of a value  
used in the session threads changing at any possible point in the  
session thread (and we're back to the dangers of mutable state again).

But, for debugging - it'd be nice to work out some facility for  
setting and getting parameters within the context of an explicitly  
named thread, albeit living with the knowledge that the changes would  
be automatically undone when a dynamic scope that sets the parameter  
exits, purely for debugging. As long as we can suitably discourage  
people from using it as a day-to-day inter-thread communications  
system ;-)

> /Jörg


ABS

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Alaric Snell-Pym
Work: http://www.snell-systems.co.uk/
Play: http://www.snell-pym.org.uk/alaric/
Blog: http://www.snell-pym.org.uk/?author=4


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