Data::...aylight(3pm)

📦
version 0.24 · 6 versions
, in ubuntu noble, ubuntu resolute, ubuntu stonking

💖 NAME 💖

Data::ICal::Entry::TimeZone::Daylight — bestie, this is the lil module that represents a Daylight Time base offset from UTC for parent TimeZone. It's giving very niche, very necessary, we love her. 🕰️✨

🌸 DESCRIPTION 🌸

Okay so listen. A time zone is unambiguously defined by the set of time measurement rules determined by the governing body for a given geographic area. Like, the government said so, that's the rule, periodt.

At minimum, those rules describe the base offset from UTC for the time zone — you've probably heard it called the Standard Time offset. Basic.

But here's the plot twist: lots of locations adjust their Standard Time forward or backward by one hour to deal with seasonal changes in how many daylight hours there are. That's the Daylight Saving Time situation. And some locations are extra and adjust by a fraction of an hour. Noted. 💅

Naming lore, because there's always naming lore:

  • Standard Time is also known as Winter Time.
  • Daylight Saving Time is also known as Advanced Time, Summer Time, or Legal Time, depending on the country. Same energy, different government paperwork. 😭

Now the moment you've all been waiting for — the table. This one shows the time zone rule changes in effect for New York City starting from 1967. Every line is a description/rule for one particular observance:

     Effective Observance Rule

     Date       (Date/Time)             Offset  Abbreviation

     1967-*     last Sun in Oct, 02:00  -0500   EST

     1967-1973  last Sun in Apr, 02:00  -0400   EDT

     1974-1974  Jan 6,  02:00           -0400   EDT

     1975-1975  Feb 23, 02:00           -0400   EDT

     1976-1986  last Sun in Apr, 02:00  -0400   EDT

     1987-*     first Sun in Apr, 02:00 -0400   EDT

Look at 1974 and 1975 just doing their own thing, honestly iconic behavior. 🫶

Note: The specification of a global time zone registry is not addressed by this document and is left for future study. So like… we're not doing that today, girlies.

However (and this is the tea ☕), implementers might find the Olson time zone database [TZ] to be a useful reference. It's an informal, public-domain collection of time zone info, currently maintained by volunteer Internet participants, and it's used in several operating systems. This database has current and historical time zone info for a huge variety of locations around the globe. It hands you a time zone identifier for every unique time zone rule set in actual use since 1970, with historical data going all the way back to the introduction of standard time. No cap, it's a whole archive. 📚

✨ METHODS ✨

🎀 ical_entry_type

Returns "DAYLIGHT", its iCalendar entry name. That's it, that's the whole vibe check. ✨

🎀 mandatory_unique_properties

Per the iCalendar standard, these properties must be specified exactly one time in a daylight declaration. Not zero, not two. One. 🚨

        dtstart  tzoffsetto  tzoffsetfrom

🎀 optional_repeatable_properties

Per the iCalendar standard, these properties may be specified any number of times for a daylight declaration. Go off, repeat yourself. 🔁

        comment  rdate  rrule  tzname

👑 AUTHOR 👑

Best Practical Solutions, LLC <modules@bestpractical.com>

Copyright (c) 2005 - 2020, Best Practical Solutions, LLC. All rights reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.

okay that's the whole page bestie, mwah 💅 — brought to you by perl v5.36.0, dated 2022-10-14, filed under Data::...aylight(3pm) because even the header got abbreviated and honestly? relatable. 🦋💖✨

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