RFC: DateTime::TemporalValue
Hi, I recently worked on a project where I had to keep track of data that changed over time. I needed to keep a history of the changes, as well as allow values to be specified for future time periods. For example, a value could be set, and it would go into effect starting now. A second value could be set that goes into effect in 2 weeks, and expires 2 weeks after that.. after which time, the original value goes back into effect. Much of what I did I borrowed from Martin Fowler's ideas on the pattern Temporal Property. I found this approach came in handy when I had to manage permissions that would change at some point in the future. After solving this problem a few times, I decided to compile it into a CPAN module and get some feedback from the perl DateTime list before releasing it. I placed the module on my website at the following location: http://www.onautopilot.com/oss Here's a small snippet from my POD to give you and idea what the interface looks like. (The POD has a more in-depth explanation of the main methods): - =head1 NAME DateTime::TemporalValue - Represent any value that changes over time =head1 SYNOPSIS use DateTime::TemporalValue; $tv = DateTime::TemporalValue-new; $tv = DateTime::TemporalValue-new($value); $tv-set($value); $tv-set($value, $dt); $tv-set($value, $dt = $dt-clone-add(months = 1)); $tv-set($value, $dt_span); $tv-set($value, $dt_span_set); $tv-set($tv_other); $value = $tv-get; $value = $tv-get($dt); $value = $tv-get($dt-clone-add(months = 1)); $value = $tv-get($dt-clone-subtract(months = 1)); @temporal_values = $tv-temporal_values; #NOTE: the variables named above, prefixed with $dt, represent #objects created by DateTime::* modules: # $dt = DateTime # $dt_span = DateTime::Span # $dt_span_set = DateTime::SpanSet - I'm certainly open to suggestions, or criticism on the code or interface. I'm not even sure this belongs under the DateTime namespace, but I figured this was the best place to start asking. Thanks, Dan Kubb Autopilot Marketing Inc.
Re: Chinese Calendar Question (fwd)
Absolutely. I've suggested DateTime::Util for helpers before. Astro::* makes sense for 'generic' astronomical calculations. DateTime specific stuff should inhabit another namespace. Okay, that makes more sense to me. How about: DateTime::Util::Calc DateTime::Util::Astro::Sun DateTime::Util::Astro::Moon DateTime::Util::Astro::Common DateTime::Util::Astro::Location ::Calc would contain things that are used for calculation, such as polynomial(). ::Sun will have solar longitude related stuff. ::Moon will have lunar longitude and new moon related calculations. ::Location is a simple class to encapsulate location on earth. ::Common will have things like nutation() and ephemeris_correction(). --d
[RFC] DateTime::Bundle::Minimal and DateTime::Bundle::Basic
I just installed Bundle::DateTime on my Darwin machine ... I hadn't looked through the docs beforehand :) Can I suggest two other bundles that I'm willing to maintain (they shouldn't need much alteration anyway. Not like the full bundle!) Bundle::DateTime::Minimal is the minimum needed to install and use DateTime.pm Bundle::DateTime::Basic contains the above, plus the extra modules required for Sets and Spans as well as the main Format modules Maybe we could also look at Bundle::DateTime::Formatters to quick-install all the formatters and Bundle::DateTime::Events to quick-install all events and DateTime::Bundle::Calendars to install all the calendars. That's more work though ... package Bundle::DateTime::Minimal; Class::Factory::Util 1.3 - prereq's of DateTime Params::Validate 0.52 Test::More 0 Time::Local 1.04 Class::Singleton 1.03 - prereq of DT::TimeZone DateTime::Locale 0.03 - needed by DateTime DateTime::TimeZone 0.25 - needed by DateTime DateTime package Bundle::DateTime::Basic; Bundle::DateTime::Minimal; DateTime::Set DateTime::Format::Strptime -- needed by DT::F::Builder DateTime::Format::Builder -- prereq of several other formats
Re: RFC: DateTime::TemporalValue
Dan Kubb wrote: I recently worked on a project where I had to keep track of data that changed over time. I needed to keep a history of the changes, as well as allow values to be specified for future time periods. DateTime::TemporalValue 082: #Class::Multimethods could really clean this up, but it doesn't work 083: #under mod_perl yet, so I can't use it. How about (untested): my $spanset = DT::SpanSet-empty_set-union( @_ ); from the docs: Set operations may be performed not only with DateTime::SpanSet objects, but also with DateTime, DateTime::Set and DateTime::Span objects. - Flavio S. Glock
Re: [RFC] DateTime::Bundle::Minimal and DateTime::Bundle::Basic
Rick Measham schreef: I just installed Bundle::DateTime on my Darwin machine ... I hadn't looked through the docs beforehand :) Can I suggest two other bundles that I'm willing to maintain (they shouldn't need much alteration anyway. Not like the full bundle!) Bundle::DateTime::Minimal is the minimum needed to install and use DateTime.pm Bundle::DateTime::Basic contains the above, plus the extra modules required for Sets and Spans as well as the main Format modules I would prefer just 1 more bundle, Bundle::DateTime, containing the mimimum needed for DateTime.pm, and a few selected other modules that don't introduce new prereq's: DT prereq's: Class::Factory::Util 1.3 - prereq's of DateTime Params::Validate 0.52 Test::More 0 Time::Local 1.04 Class::Singleton 1.03 - prereq of DT::TimeZone DateTime::Locale 0.03 - needed by DateTime DateTime::TimeZone 0.25 - needed by DateTime DateTime your choices for basic: DateTime::Set DateTime::Format::Strptime -- needed by DT::F::Builder DateTime::Format::Builder -- prereq of several other formats my additions: DateTime::Format::HTTP DateTime::Format::ISO8601 DateTime::Format::Mail Maybe we could also look at Bundle::DateTime::Formatters to quick-install all the formatters and Bundle::DateTime::Events to quick-install all events and DateTime::Bundle::Calendars to install all the calendars. That's more work though ... I can't imagine anyone else but a kalendrophile installing all calendars, or all events, and kalendrophiles can just install Bundle::DateTime::Complete. (I created Bundle::DateTime for myself, to have a simple method of getting all DT modules; I don't think it's the best way to install DateTime.pm, so I wouldn't mind renaming it to B::DT::Complete. With the name as it is, a query for DateTime in the CPAN.pm shell will return both DateTime.pm and Bundle/DateTime.pm, which is not good.) Eugene
Re: [RFC] DateTime::Bundle::Minimal and DateTime::Bundle::Basic
Dave Rolsky schreef: On Wed, 22 Oct 2003, Eugene van der Pijll wrote: DT prereq's: Class::Factory::Util 1.3 - prereq's of DateTime Params::Validate 0.52 Test::More 0 Time::Local 1.04 Class::Singleton 1.03 - prereq of DT::TimeZone DateTime::Locale 0.03 - needed by DateTime DateTime::TimeZone 0.25 - needed by DateTime DateTime I don't get how this is useful. If you use CPAN or CPANPLUS to install DateTime, it will tell you that you need these prereqs anyway. The first few versions of Bundle::DateTime left out those prereqs. As a result, the bundle was difficult to install for the first time: I can't remember exactly what happened, but DateTime couldn't be installed first time round because of its prereqs; the prereqs were installed; then CPAN first tried to install all other modules in Bundle::DateTime before installing DateTime itself, and each installation failed of course... The best solution seemed to be to include the prereqs in the Bundle. Eugene
Re: [RFC] DateTime::Bundle::Minimal and DateTime::Bundle::Basic
Dave Rolsky schreef: DateTime, it will tell you that you need these prereqs anyway. Eugene van der Pijll [EMAIL PROTECTED] wrote: The first few versions of Bundle::DateTime left out those prereqs. As a result, the bundle was difficult to install for the first time: A good point Dave, so there's really no need for Bundle::DateTime::Minimal, as you get the same thing by just installing DateTime with CPAN. So then we're left with the other bundle, which Eugene has suggested calling Bundle::DateTime, and moving the existing bundle to Bundle::DateTime::Complete. That sounds like a good idea, however I'm not sure about including DT::F::Mail and DT::F::HTTP. They seem to be fairly specific-task oriented modules. I admit that they're probably common tasks, but if I wanted a quick way to get up and going with DateTime, but it was for DBI, I'd be annoyed that I was getting net-related modules. I'm open to including them, just a little disinclined. Cheers! Rick P.S. Eugene: as you point out, you need to include all prerequisites in the bundle. It also seems that the order is of the utmost importance. I had to install the current bundle at least four times before it got everything installed. I wondered if that could be because it installs the modules in the order in the file rather than downloading them all and checking prereq's first. On the other hand I seem to recall CPAN.pm didn't fully install before it went on to the next one.. maybe I have an old CPAN. Cheers more! Rick
Re: [RFC] DateTime::Bundle::Minimal and DateTime::Bundle::Basic
Also, regarding DTF::HTTP suitability, it has a requirement of HTTP::Date which is part of LWP. This probably counts against it for bundling (though most people using bundles probably have LWP already). cheers, -- Iain. http://eh.org/~koschei/ pgp0.pgp Description: PGP signature
[RFC] Astro related modules
I've now re-organized the astronomical calculation portions of the chinese calendar modules into the following. This should be nicer to the namespace. Please let me know if they look ok: http://www.wafu.ne.jp/~daisuke/DateTime-Util-Calc-0.01.tar.gz http://www.wafu.ne.jp/~daisuke/DateTime-Util-Astro-0.01.tar.gz http://www.wafu.ne.jp/~daisuke/DateTime-Event-Lunar-0.01.tar.gz I also plan to create Astro::Event::SolarTerm, which will allow me to partition things nicely within my planned DT::C::Chinese and DT::C::Japanese. --d
