>From 9a608596c8c16083325c96e76fd3029144167acc Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Tue, 19 Feb 2019 11:15:24 -0800 Subject: [PROPOSED] Add Vietnam commentary and fluidity guideline * asia: Add commentary about Vietnam other than Ho Chi Minh City. * theory.html (Names of timezones): Mention the problem of fluid boundaries between timezones. --- asia | 12 ++++++++++++ theory.html | 6 ++++++ 2 files changed, 18 insertions(+) diff --git a/asia b/asia index 3165203..5d0af02 100644 --- a/asia +++ b/asia @@ -3596,5 +3596,17 @@ Zone Asia/Ho_Chi_Minh 7:06:40 - LMT 1906 Jul 1 8:00 - +08 1975 Jun 13 7:00 - +07 +# From Paul Eggert (2019-02-19): +# +# The Ho Chi Minh entry suffices for most purposes as it agrees with all of +# Vietnam since 1975-06-13. Presumably clocks often changed in south Vietnam +# in the early 1970s as locations changed hands during the war; however the +# details are unknown and would likely be too voluminous for this database. +# +# For timestamps in north Vietnam back to 1970 (the tzdb cutoff), +# use Asia/Bankgok; see the VN entries in the file zone1970.tab. +# For timestamps before 1970, see Asia/Hanoi in the file 'backzone'. + + # Yemen # See Asia/Riyadh. diff --git a/theory.html b/theory.html index 5ea1369..8f079b9 100644 --- a/theory.html +++ b/theory.html @@ -227,6 +227,12 @@ in decreasing order of importance: even if some of the clocks disagreed before 1970. Otherwise these tables would become annoyingly large. +
  • + If boundaries between regions are fluid, such as during a war or + insurrection, do not bother to create a new timezone merely + because of yet another boundary change. This helps prevent table + bloat and simplifies maintenance. +
  • If a name is ambiguous, use a less ambiguous alternative; e.g., many cities are named San Jos�� and Georgetown, so -- 2.20.1