[Newbies] #Schedule - How to Use?

[David T. Lewis]

On Thu, Jun 27, 2019 at 07:00:08PM -0700, John-Reed Maffeo wrote:
> David,
> 
> Thank you! Your observation about #Schedule, it seems to be correct. I have
> been trying things out since I sent my original question and came to the
> same conclusion,  it just builds a collection of #DateAndTime objects which
> may be useful in conjunction with #Delay.
> 
> Some tests with #Delay in a current 64 bit image produce results which
> produce results which exceed the limit of ~six days which I mentioned in my
> original post. I got the limit from the Delay
> <http://wiki.squeak.org/squeak/3134> entry on the Squeak Wiki.

It is quite possible that the six day limit goes away on a 64 bit
image (I did not check) because SmallInteger is not small any more :-)

As a side note, you can delay for 365 days like this:

  d := 1 day asDelay.
  365 timesRepeat: [ d wait ].

But relying on long delays to execute a schedule does not sound like
a very good idea anyway, so the Scheduler package by John Pierce sounds
like a good tip.

If you are concerned with tracking daylight savings time changes in
your schedules, the TZ-Olson package on SqueakMap may be useful (latest
Squeak trunk only).

Dave


> 
> So I have two options to investigate now #Delay and #Scheduler.
> 
> Thanks for looking up Torsten's version. I had seen a mention of it, but I
> was trying to stay within the bounds of a standard release. I will take a
> look.
> 
> Regards,
> 
> -jrm
> 
> P.S. For someone who has been away from Squeak for a long time, you still
> have very good advice to share :-)
> 
> On Thu, Jun 27, 2019 at 6:34 PM David Shaffer <cdshaffer at acm.org> wrote:
> 
> > I???ve been away from Squeak for a long time but I don???t think Schedule does
> > what you want.  I browsed the code a bit and it seems to be more about
> > /storing/ a schedule rather than /executing/ one.
> >
> > John Pierce wrote a package called Scheduler which I used with great
> > success many (many) years ago.  The SqueakMap entry still exists but the
> > file links are dead.  I have attached my latest version of that package.  I
> > tried it out in Squeak 5.2 and it seemed to work but I can???t make any
> > promises.  I don???t think it will have the same problems as a long Delay
> > since its main loop seems to check for runnable tasks every 1/4 second.
> >
> > The SqueakMap page has some docs:
> > http://map.squeak.org/package/cb344d5b-c810-45cd-a440-534d900aacfd
> >
> > BTW, to load the MCZ you can use the File List (under Tools).
> >
> > Best,
> >
> > David
> >
> >
> > On Jun 24, 2019, at 5:16 PM, John-Reed Maffeo <jrmaffeo at gmail.com> wrote:
> >
> > I am working on an application which requires task scheduler like cron on
> > UNIX or Task Manager on Windows. In the swiki , there is a page about Refactored
> > Date and Time Classes <http://wiki.squeak.org/squeak/1871> which mentions
> > #Schedule in the context of TV programs. I have figured out how to set up,
> > but I can not figure out how to use it productively.
> >
> > My simple use case is:
> > a. create an instance of #Schedule
> > b. Use the schedule to write a string to the Transcript based on the
> > contents of the schedule.
> >
> >
> > |sampleSchedule  rightNow cr |
> >
> > rightNow := DateAndTime now.
> > cr := String cr.
> >
> > sampleSchedule := Schedule starting: rightNow  ending: rightNow + 20
> > minutes .
> >
> > sampleSchedule schedule: {Duration minutes: 1. Duration minutes: 3}.
> > sampleSchedule  scheduleDo:[:each |Transcript show: each asString, String
> > cr].
> > >> This results in all of the schedule items being written to the
> > Transcript immediately, rather at the schedule time for each.
> >
> > How to I use a schedule to run a block at the time specified by the
> > schedule.
> >
> > I have looked at #Delay, but it has a limit of ~six days which will not
> > work for me.
> >
> > Thanks,
> >
> > -jrm
> >
> >
> >
> >
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