[Twisted-Python] a question about monotonic clock

[Glyph]

On Oct 29, 2012, at 10:52 AM, Phil Mayers <p.mayers at imperial.ac.uk> wrote:

> On 29/10/12 09:59, Tristan Seligmann wrote:
> 
>> I don't think anyone in this thread is arguing *against* implementing
>> this functionality; I think the point was just that this functionality
>> is only of critical importance under a limited range of circumstances,
>> as opposed to being something of urgent need for every Twisted-using
>> program that needs to schedule timed events.
> 
> I think this is a pretty good summary; it's rare to need this (though 
> often essential when you do) and it's also hard. TBH I'm not sure there 
> are any sensible semantics for a lot of the cases - the best the 
> framework can do is give the app an option for clocks, and try to give 
> them as much info as possible about how they've advanced or not.

Right; callLater is not quite expressive enough.  I wouldn't want to expose the whole mess of clock nonsense to every application, but it would be necessary to split callLater into "callAfter" (delay a certain number of seconds from "now", to within a best guess, regardless of clock changes) and "callAt" (call as close as possible to a certain calendar time, respecting clock changes).

-glyph