commit b84158453d6b3015641fb9647b16626127e6f972
parent bb31979d91647ecf8b125b5644acbf5bd12058ee
Author: Byron Torres <b@torresjrjr.com>
Date: Sat, 12 Mar 2022 16:27:24 +0000
brush up comments and code for review
Signed-off-by: Byron Torres <b@torresjrjr.com>
Diffstat:
8 files changed, 51 insertions(+), 44 deletions(-)
diff --git a/datetime/arithmetic.ha b/datetime/arithmetic.ha
@@ -2,14 +2,6 @@ use fmt;
use time::chrono;
use time;
-fn absi(n: i64) i64 = {
- if (n < 0) {
- return -n;
- } else {
- return n;
- };
-};
-
// Represents a span of time in the proleptic Gregorian calendar,
// using relative units of time. Used for calendar arithmetic.
export type period = struct {
@@ -419,6 +411,15 @@ export fn subtract(dt: datetime, flag: calculus, pp: period...) datetime = {
return add(dt, flag, pp...);
};
+// Copied from math:: to avoid dependancy.
+fn absi(n: i64) i64 = {
+ if (n < 0) {
+ return -n;
+ } else {
+ return n;
+ };
+};
+
@test fn eq() void = {
const dt = new(2022, 02, 04, 03, 14, 07, 00, 0, chrono::UTC_Z)!;
const cases = [
diff --git a/datetime/datetime.ha b/datetime/datetime.ha
@@ -108,7 +108,7 @@ export fn new(
// `invaliddatetime = !void` ?
// `invaliddatetime = !datetime::builder` ?
) (datetime | errors::invalid) = {
- // TODO: set the correct values according to the given zoffset and
+ // TODO: Set the correct values according to the given zoffset and
// locality/timezone.
let m = chrono::new(
calc_epochal_from_ymd(year, month, day)?,
@@ -118,16 +118,17 @@ export fn new(
// figuring out what zone this moment observes
if (zoffset is time::duration) {
- // transform inversely to the moment that would transform back
+ // Transform inversely to the moment that would transform back
// to the current moment, then perform a zone lookup.
m = chrono::transform(m, -(zoffset as time::duration));
chrono::lookupzone(&m);
} else {
- // just perform a zone lookup, then try that zone and the
- // zones that are observed before and after.
+ // Just perform a zone lookup, then try that zone and the
+ // zones that are observed before and after. This requires
+ // knowlegde of the transition index.
//const z0 = chrono::lookupzone(*m);
//m = chrono::transform(m, -z0.zoffset);
- void;
+ abort("TODO"); // TODO
};
const dt = from_moment(m);
@@ -158,7 +159,7 @@ export fn now() datetime = {
// Creates a copy of a [[datetime]]
//
-// TODO: remove, seems useless.
+// TODO: remove, purge from other functions, seems useless.
export fn clone(dt: datetime) datetime = dt;
// Creates a [[datetime]] from a [[chrono::moment]]
diff --git a/datetime/format.ha b/datetime/format.ha
@@ -51,7 +51,7 @@ def MONTHS_SHORT: [_]str = [
// Parses a datetime string into a [[builder]], using a "layout" format string
// with a subset of specifiers from POSIX strptime(3). Partial, incremental
-// parsing is allowed.
+// parsing is possible.
//
// datetime::parse(&b, "%Y-%m-%d", "2038-01-19");
// datetime::parse(&b, "%H:%M:%S", "03:14:07");
diff --git a/datetime/time.ha b/datetime/time.ha
@@ -3,6 +3,8 @@ use time;
// Calculates the wall clock (hour, minute, second, nanosecond),
// given a time since the start of a day
+//
+// TODO: implement special case for leap seconds where this function is called.
fn calc_hmsn(t: time::duration) (int, int, int, int) = {
const hour = (t / time::HOUR): int;
const min = ((t / time::MINUTE) % 60): int;
diff --git a/time/arithm.ha b/time/arithm.ha
@@ -20,7 +20,7 @@ export fn diff(a: instant, b: instant) duration = {
// 0 if a and b are simultaneous;
// +1 if b precedes a;
//
-// Notes:
+// XXX:
// At first seems superceded by elapsed, but useful when you need values at
// compile time:
// switch (compare(a, b)) {
diff --git a/time/chrono/README b/time/chrono/README
@@ -1,6 +1,11 @@
The time::chrono submodule provides the basis for chronology in Hare,
namely [[timescale]]s (leap second handling), [[timezone]]s, and the
-[[moment]] type, an abstracted datetime for calendars to interface with.
+[[moment]] type, an abstracted datetime for external modules to
+interface with.
For working with the ISO 8601 Gregorian calendar, see the [[datetime]]
submodule.
+
+Hare defines a chronology as a system used to name and order moments in
+time. In practice, a chronology is the combination of a calendar (for
+handling days) and a wall clock (for handling times throughout a day).
diff --git a/time/chrono/leapsec.ha b/time/chrono/leapsec.ha
@@ -1,36 +1,28 @@
use time;
-// UTC timestamps and their TAI offsets, sourced from leap-seconds.list
-// updated: 8 July 2016
-// expires: 28 June 2022
-//
-// TODO:
-// this is a temporary hard-coded list. read leap-second data from a source.
-//
-// Separating concerns of timezones and timescale has proven troublesome, since
-// data of timezone transitions and leap seconds are both encoded in the TZif
-// files generated from the Olson/tz project, and typically installed at
-// /usr/share/zoneinfo. Thus, for typical programs in a minimal system like
-// Alpine, the entire system can only be configured to run either with or
-// without adherence to leap second information.
+// Hare uses raw leap second informtion when dealing with the UTC and TAI
+// timescales. This information is source from a standard file installed at
+// /usr/share/zoneinfo/leap-seconds.list, which itself is fetched from and
+// periodically maintained at:
//
-// Olson himself has expressed for the support of Martian time, which with our
-// approach, may depend on multi-timescale support:
+// <ftp://ftp.nist.gov/pub/time/leap-seconds.list>
+// <ftp://ftp.boulder.nist.gov/pub/time/leap-seconds.list>
//
-// > The tz database does not currently support Mars time, but it is documented
-// > here in the hopes that support will be added eventually. 8
+// This is in contrast to legacy systems which rely on TZif files, which are
+// installed typically at /usr/share/zoneinfo, as part of the "Olson" IANA
+// Timezone databse. These files couple timezone and leap second information
+// into one datablock.
//
-// Some systems have an ideal /usr/share/zoneinfo/leap-seconds.list file, which
-// is directly downloaded from a periodically maintained file at
-// <ftp://ftp.nist.gov/pub/time/leap-seconds.list> or
-// <ftp://ftp.boulder.nist.gov/pub/time/leap-seconds.list>. This file contains a
-// list of Unix timestamps (2272060800) and absolute timescale offsets (+10). A
-// good solution ought to use this.
+// Depending on a system's installation, leap second information may be
+// deliberately left out of the TZif files, or duplicated throughout. This
+// design also inhibits our ambitions for dealing with multiple, dynamic
+// timescales. Therefore, we have decided to take an alternative approach.
+
+// UTC timestamps and their TAI offsets, sourced from leap-seconds.list
+// updated: 8 July 2016
+// expires: 28 June 2022
//
-// Some systems have a less ideal /usr/share/zoneinfo/leapseconds file, which is
-// generated from leap-seconds.list using an awk script, and contains Gregorian
-// datetime timestamps (1972 Jun 30 23:59:60) and relative timescale corrections
-// (+S, -S). This may be a fallback solution.
+// TODO: Initialise this data from /usr/share/zoneinfo/leap-seconds.list
const leaps_utc: [](i64, i64) = [
(2272060800, 10),
(2287785600, 11),
diff --git a/time/chrono/timescale.ha b/time/chrono/timescale.ha
@@ -151,6 +151,12 @@ fn conv_tt_tai(tt: time::instant) (time::instant | time::error) = {
};
+// Authur David Olson had expressed for Martian time support in this database
+// project <https://data.iana.org/time-zones/theory.html>:
+//
+// > The tz database does not currently support Mars time, but it is documented
+// > here in the hopes that support will be added eventually. 8
+
// Coordinated Mars Time
//
// Used for local solar time on Mars.
