[vwnc] How to model time and date as first class entity?

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[vwnc] How to model time and date as first class entity?

Thomas Schrader
Hi everybody,

I've got a problem with the date and time model in some biggish manufacturing
planning and stockkeeping system and would like to ask for your help.

Time and date IMHO needs to be a first class entity in that system under
inspection, but it actually isn't. So, there potentially are thousands of buggy
or inconsistent uses of Date, Time, Timestamp and even ByteArray to calculate
time and date, and I'm very interested in your experiences with time and date
models in VW Smalltalk.

Is there some reliable VW solution, already? How do you control the complexity
of time input, scheduling, calendar calculations and display transformations?

Thanks a lot

Thomas

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Re: [vwnc] How to model time and date as first class entity?

Terry Raymond
Thomas

It depends on a lot of factors;
        - Do you need to operate across time zones?
        - Is the performance of time calculations a concern?
        - How long a time spand do you need to be concerned with?
        - Do you need to print time and date in several different
          formats?

Most of the concerns relate to trading off time calculation
performance with what needs to be represented. If you are not
careful, time calculations can end up using LargeInteger arithmetic,
something that is a big performance hit.

Terry
 
===========================================================
Terry Raymond
Crafted Smalltalk
80 Lazywood Ln.
Tiverton, RI  02878
(401) 624-4517      [hidden email]
<http://www.craftedsmalltalk.com>
===========================================================

> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of Thomas Schrader
> Sent: Monday, November 03, 2008 9:24 AM
> To: [hidden email]
> Subject: [vwnc] How to model time and date as first class entity?
>
> Hi everybody,
>
> I've got a problem with the date and time model in some biggish manufacturing
> planning and stockkeeping system and would like to ask for your help.
>
> Time and date IMHO needs to be a first class entity in that system under
> inspection, but it actually isn't. So, there potentially are thousands of buggy
> or inconsistent uses of Date, Time, Timestamp and even ByteArray to calculate
> time and date, and I'm very interested in your experiences with time and date
> models in VW Smalltalk.
>
> Is there some reliable VW solution, already? How do you control the complexity
> of time input, scheduling, calendar calculations and display transformations?
>
> Thanks a lot
>
> Thomas
>
> --
>
> mailto thomas j schrader at web de
>
> _______________________________________________________________________
> Jetzt neu! Schützen Sie Ihren PC mit McAfee und WEB.DE. 30 Tage
> kostenlos testen. http://www.pc-sicherheit.web.de/startseite/?mc=022220
>
>
> _______________________________________________
> vwnc mailing list
> [hidden email]
> http://lists.cs.uiuc.edu/mailman/listinfo/vwnc


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Re: [vwnc] How to model time and date as first class entity?

hernan.wilkinson
Hi Thomas,
 we wrote a hole new Time model because we had the same issues as you mention for our financial app. The model is open source and it is called Chalten (it is available for Squeak, VW and VisualAge) and you can download it from the Cincom's public repository.
 You will see that dates, times, days, days of months, years, month of years, time filters (working days, non working days), calendars, etc. are all first class objects. We wrote a paper about it, if you want a copy let me know. Maximiliano Taborda added support for other calendars such as the Irish and some Arabic ones. Hope this help.

 Bye,
 Hernan.

On Mon, Nov 3, 2008 at 1:16 PM, Terry Raymond <[hidden email]> wrote:
Thomas

It depends on a lot of factors;
       - Do you need to operate across time zones?
       - Is the performance of time calculations a concern?
       - How long a time spand do you need to be concerned with?
       - Do you need to print time and date in several different
         formats?

Most of the concerns relate to trading off time calculation
performance with what needs to be represented. If you are not
careful, time calculations can end up using LargeInteger arithmetic,
something that is a big performance hit.

Terry

===========================================================
Terry Raymond
Crafted Smalltalk
80 Lazywood Ln.
Tiverton, RI  02878
(401) 624-4517      [hidden email]
<http://www.craftedsmalltalk.com>
===========================================================

> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of Thomas Schrader
> Sent: Monday, November 03, 2008 9:24 AM
> To: [hidden email]
> Subject: [vwnc] How to model time and date as first class entity?
>
> Hi everybody,
>
> I've got a problem with the date and time model in some biggish manufacturing
> planning and stockkeeping system and would like to ask for your help.
>
> Time and date IMHO needs to be a first class entity in that system under
> inspection, but it actually isn't. So, there potentially are thousands of buggy
> or inconsistent uses of Date, Time, Timestamp and even ByteArray to calculate
> time and date, and I'm very interested in your experiences with time and date
> models in VW Smalltalk.
>
> Is there some reliable VW solution, already? How do you control the complexity
> of time input, scheduling, calendar calculations and display transformations?
>
> Thanks a lot
>
> Thomas
>
> --
>
> mailto thomas j schrader at web de
>
> _______________________________________________________________________
> Jetzt neu! Schützen Sie Ihren PC mit McAfee und WEB.DE. 30 Tage
> kostenlos testen. http://www.pc-sicherheit.web.de/startseite/?mc=022220
>
>
> _______________________________________________
> vwnc mailing list
> [hidden email]
> http://lists.cs.uiuc.edu/mailman/listinfo/vwnc


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Re: [vwnc] How to model time and date as first class entity?

Joseph Bacanskas-4
In reply to this post by Thomas Schrader
Hi Thomas:

Have you looked at the Chronos package?


On Nov 3, 2008, at 6:23 AM, Thomas Schrader wrote:

> Hi everybody,
>
> I've got a problem with the date and time model in some biggish  
> manufacturing
> planning and stockkeeping system and would like to ask for your help.
>
> Time and date IMHO needs to be a first class entity in that system  
> under
> inspection, but it actually isn't. So, there potentially are  
> thousands of buggy
> or inconsistent uses of Date, Time, Timestamp and even ByteArray to  
> calculate
> time and date, and I'm very interested in your experiences with time  
> and date
> models in VW Smalltalk.
>
> Is there some reliable VW solution, already? How do you control the  
> complexity
> of time input, scheduling, calendar calculations and display  
> transformations?
>
> Thanks a lot
>
> Thomas
>
> --
>
> mailto thomas j schrader at web de
>
> _______________________________________________________________________
> Jetzt neu! Schützen Sie Ihren PC mit McAfee und WEB.DE. 30 Tage
> kostenlos testen. http://www.pc-sicherheit.web.de/startseite/?
> mc=022220
>
>
> _______________________________________________
> vwnc mailing list
> [hidden email]
> http://lists.cs.uiuc.edu/mailman/listinfo/vwnc

Thanks!!
Joseph Bacanskas [|]
--- I use Smalltalk.  My amp goes to eleven.


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Re: [vwnc] How to model time and date as first class entity?

Thomas Schrader
In reply to this post by Thomas Schrader
Hi Terry, Hernan, Joseph,

> ... Chalten ...
> ... Chronos ...

that all sounds very well to me. I'll try them out and see
what I can learn from them.

> It depends on a lot of factors ...
> Most of the concerns relate to trading off time calculation performance

I'm always careful about that and see how far I can go with
the packages.

Thanks a lot
 
Thomas Schrader

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