Add DateTime + Duration overloads.

lib/std/time/clock.c3

@@ -23,11 +23,21 @@ fn Clock Clock.add_nano_duration(self, NanoDuration nano) @operator_s(+) @inline
 	return (Clock)((NanoDuration)self + nano);
 }
 
+fn Clock Clock.sub_nano_duration(self, NanoDuration nano) @operator(-) @inline
+{
+	return (Clock)((NanoDuration)self - nano);
+}
+
 fn Clock Clock.add_duration(self, Duration duration) @operator_s(+) @inline
 {
 	return self.add_nano_duration(duration.to_nano());
 }
 
+fn Clock Clock.sub_duration(self, Duration duration) @operator(-) @inline
+{
+	return self.sub_nano_duration(duration.to_nano());
+}
+
 fn NanoDuration Clock.nano_diff(self, Clock other) @operator(-) @inline
 {
 	return (NanoDuration)self - (NanoDuration)other;

lib/std/time/datetime.c3

@@ -149,6 +149,8 @@ fn void DateTime.set_time(&self, Time time)
 	self.time = time;
 }
 
+fn DateTime DateTime.add_us(&self, Duration d) @operator_s(+) => from_time(self.time + d);
+fn DateTime DateTime.sub_us(&self, Duration d) @operator(-) => from_time(self.time - d);
 fn DateTime DateTime.add_seconds(&self, int seconds) => from_time(self.time.add_seconds(seconds));
 fn DateTime DateTime.add_minutes(&self, int minutes) => from_time(self.time.add_minutes(minutes));
 fn DateTime DateTime.add_hours(&self, int hours) => from_time(self.time.add_hours(hours));
@@ -187,6 +189,8 @@ fn DateTime DateTime.add_months(&self, int months)
 }
 
 
+fn TzDateTime TzDateTime.add_us(&self, Duration d) @operator_s(+) => self.date_time.add_us(d).to_gmt_offset(self.gmt_offset);
+fn TzDateTime TzDateTime.sub_us(&self, Duration d) @operator(-) => self.date_time.sub_us(d).to_gmt_offset(self.gmt_offset);
 fn TzDateTime TzDateTime.add_seconds(&self, int seconds) => self.date_time.add_seconds(seconds).to_gmt_offset(self.gmt_offset);
 fn TzDateTime TzDateTime.add_minutes(&self, int minutes) => self.date_time.add_minutes(minutes).to_gmt_offset(self.gmt_offset);
 fn TzDateTime TzDateTime.add_hours(&self, int hours) => self.date_time.add_hours(hours).to_gmt_offset(self.gmt_offset);
@@ -248,7 +252,8 @@ fn double DateTime.diff_sec(self, DateTime from)
 {
 	return (double)self.time.diff_us(from.time) / (double)time::SEC;
 }
-fn Duration DateTime.diff_us(self, DateTime from)
+
+fn Duration DateTime.diff_us(self, DateTime from) @operator(-)
 {
 	return self.time.diff_us(from.time);
 }

lib/std/time/time.c3

@@ -88,6 +88,7 @@ fn Time Time.add_hours(time, long hours) => time + hours * HOUR;
 fn Time Time.add_days(time, long days) => time + days * DAY;
 fn Time Time.add_weeks(time, long weeks) => time + weeks * WEEK;
 fn Time Time.add_duration(time, Duration duration) @operator_s(+) @inline => (Time)((long)time + (long)duration);
+fn Time Time.sub_duration(time, Duration duration) @operator(-) @inline => (Time)((long)time - (long)duration);
 
 fn int Time.compare_to(time, Time other)
 {

releasenotes.md

@@ -18,6 +18,7 @@
 - Add `String.tokenize_all` to replace the now deprecated `String.splitter`
 - Add `String.count` to count the number of instances of a string.
 - Add `Duration * Int` and `Clock - Clock` overload. 
+- Add `DateTime + Duration` overloads.
 
 ## 0.7.1 Change list
 

test/unit/stdlib/time/datetime.c3

@@ -3,7 +3,7 @@ import std::time;
 
 fn void test_parse_and_add()
 {
-DateTime d = datetime::from_date(1973, APRIL, 27);
+	DateTime d = datetime::from_date(1973, APRIL, 27);
 	assert(d.year == 1973);
 	assert(d.month == APRIL);
 	assert(d.day == 27);
@@ -42,6 +42,11 @@ DateTime d = datetime::from_date(1973, APRIL, 27);
     x = d.add_months(0);
     assert(x.year == 1975);
     assert(x.month == MAY);
+    test::eq(x.day, 4);
+    x = d + time::DAY;
+    test::eq(x.day, 5);
+    x = x - time::DAY;
+    test::eq(x.day, 4);
 }
 
 fn void test_timezone()
@@ -107,6 +112,10 @@ fn void test_timezone()
 	//   keeping the others unchanged. The gmt_offset should be kept as well.
 	dt = d1.add_hours(1);
 	assert(dt.day == 15);
+    dt = dt + time::DAY;
+    test::eq(dt.day, 16);
+    dt = dt - time::DAY;
+    test::eq(dt.day, 15);
 	assert(dt.hour == 1);
 	tz = d2.add_hours(1);
 	assert(tz.day == 15);

test/unit/stdlib/time/time.c3

@@ -9,6 +9,8 @@ fn void time_diff()
 	test::eq(t2 - t, time::SEC);
 	test::ne(t, t2);
 	test::eq(t, t);
+	t2 = t2 - time::SEC;
+	test::eq(t, t2);
 }
 
 fn void clock_diff()
@@ -18,6 +20,8 @@ fn void clock_diff()
 	test::eq(c2 - c, time::SEC.to_nano());
 	c2 = c + time::DAY;
 	test::eq(c2 - c, time::DAY.to_nano());
+	c2 = c2 - time::DAY;
+	test::eq(c2, c);
 }
 
 fn void to_format()