From 1babb91d01dd2c4c4990fe5d4c19ffb454849a60 Mon Sep 17 00:00:00 2001 From: daurnimator Date: Sat, 23 Nov 2013 10:54:04 -0500 Subject: [PATCH] Document tzinfo --- doc/tzinfo.md | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 doc/tzinfo.md diff --git a/doc/tzinfo.md b/doc/tzinfo.md new file mode 100644 index 0000000..d989102 --- /dev/null +++ b/doc/tzinfo.md @@ -0,0 +1,41 @@ +# `luatz.tzinfo` + +Provides a metatable for the timezone class. + +Created in `luatz.tzfile` and managed by `luatz.tzcache`; +a timezone object contains information about a timezone. +These objects are based on the information available in a "zoneinfo" file. + +Timezone objects should be considered opaque and immutable; +so the following details can be skipped over. + +------------------------------------------------------------------------------ + +The table contains a sequence of tables that describe the timezone at a given point +using a `transition_time`: the unix timestamp (in UTC) that this definition starts, and +a `info` table, which contains information about the change at that point: + + - `gmtoff` (number) The offset from GMT (UTC) in seconds + - `isdst` (boolean): If this change was declared as daylight savings + - `abbrind` (number, abbreviation id) + - `abbr` (string): short name for this gmt offset + - `isstd` (boolean) + - `isgmt` (boolean) + +## `:find_current ( utc_ts )` + +Returns the relevant `info` table at the given utc timestamp for the given UTC timestamp. + + +## `:localize ( utc_ts )` + +Convert the given UTC timestamp to the timezone. +Returns the number of seconds since unix epoch in the given timezone. + + +## `:utctime ( local_ts )` + +Convert the given local timestamp (seconds since unix epoch in the time zone) to a UTC timestamp. +This may result in ambigous results, in which case multiple values are returned. + +e.g. consider that when daylight savings rewinds your local clock from 3am to 2am there will be two 2:30ams. -- 2.39.5