New Clock.ToTime method added

Author: rickb777

clock/clock.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package clock specifies a time of day with resolution to the nearest millisecond.
+// Package clock specifies a time of day with resolution to the nearest nanosecond.
 package clock
 
 import (
@@ -69,6 +69,7 @@ func New(hour, minute, second, millisec int) Clock {
 }
 
 // NewAt returns a new [Clock] with specified hour, minute, seconds (to nanosecond resolution).
+// The date and timezone information is discarded.
 func NewAt(t time.Time) Clock {
 	hour, minute, second := t.Clock()
 	hx := Clock(hour) * Hour
@@ -78,16 +79,23 @@ func NewAt(t time.Time) Clock {
 	return hx + mx + sx + ns
 }
 
-// SinceMidnight returns a new [Clock] based on a duration since some arbitrary midnight.
+// SinceMidnight returns a new [Clock] based on a duration since midnight.
 func SinceMidnight(d time.Duration) Clock {
 	return Clock(d)
 }
 
-// DurationSinceMidnight convert a [Clock] to a [time.Duration] since some arbitrary midnight.
+// DurationSinceMidnight convert a [Clock] to a [time.Duration] since midnight.
 func (c Clock) DurationSinceMidnight() time.Duration {
 	return time.Duration(c)
 }
 
+// ToTime converts the clock and a given date to a [time.Time].
+// For example, given a date.Date d, use c.ToTime(d.Date()).
+func (c Clock) ToTime(year int, month time.Month, day int) time.Time {
+	return time.Date(year, month, day,
+		c.Hour(), c.Minute(), c.Second(), c.Nanosecond(), time.UTC)
+}
+
 // Add returns a new [Clock] offset from this clock specified hour, minute, second and millisecond.
 // The parameters can be negative.
 //
@@ -149,7 +157,7 @@ func (c Clock) IsMidnight() bool {
 
 // TruncateMillisecond discards any fractional digits within the millisecond represented by c.
 // For example, for 10:20:30.456111222 this will return 10:20:30.456.
-// This method will force the [Clock.String] method to limit its output to three decimal places.
+// This method will also force the [Clock.String] method to limit its output to three decimal places.
 func (c Clock) TruncateMillisecond() Clock {
 	return (c / Millisecond) * Millisecond
 }

clock/clock_test.go

@@ -2,14 +2,16 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package clock
+package clock_test
 
 import (
 	"fmt"
 	"testing"
 	time "time"
 
 	"github.com/govalues/decimal"
+	"github.com/rickb777/date/v2"
+	. "github.com/rickb777/date/v2/clock"
 	"github.com/rickb777/period"
 )
 
@@ -66,6 +68,28 @@ func TestClockSinceMidnight(t *testing.T) {
 	}
 }
 
+func TestClockToTime(t *testing.T) {
+	cases := []struct {
+		c   Clock
+		in  date.Date
+		exp time.Time
+	}{
+		{
+			c:   New(4, 25, 6, 999),
+			in:  date.New(2001, 2, 3),
+			exp: time.Date(2001, 2, 3, 4, 25, 6, 999_000_000, time.UTC),
+		},
+	}
+	for i, x := range cases {
+		t.Run(fmt.Sprintf("%d %s", i, x.c), func(t *testing.T) {
+			a := x.c.ToTime(x.in.Date())
+			if !a.Equal(x.exp) {
+				t.Errorf("%d: got %v, want %v (%d)", i, a, x.exp, x.c)
+			}
+		})
+	}
+}
+
 func TestClockIsInOneDay(t *testing.T) {
 	cases := []struct {
 		in   Clock

go.mod

@@ -7,7 +7,7 @@ toolchain go1.24.2
 require (
 	github.com/govalues/decimal v0.1.36
 	github.com/rickb777/period v1.0.21
-	golang.org/x/text v0.31.0
+	golang.org/x/text v0.32.0
 )
 
 require github.com/rickb777/plural v1.4.7 // indirect

go.sum

@@ -12,3 +12,5 @@ github.com/rickb777/plural v1.4.7 h1:rBRAxp9aTFYzWTLWIE/UTwKcaqSSAV2ml7aOUFYpAGo
 github.com/rickb777/plural v1.4.7/go.mod h1:DB19dtrplGS5s6VJVHn7tvmFYPoE83p1xqio3oVnNRM=
 golang.org/x/text v0.31.0 h1:aC8ghyu4JhP8VojJ2lEHBnochRno1sgL6nEi9WGFGMM=
 golang.org/x/text v0.31.0/go.mod h1:tKRAlv61yKIjGGHX/4tP1LTbc13YSec1pxVEWXzfoeM=
+golang.org/x/text v0.32.0 h1:ZD01bjUt1FQ9WJ0ClOL5vxgxOI/sVCNgX1YtKwcY0mU=
+golang.org/x/text v0.32.0/go.mod h1:o/rUWzghvpD5TXrTIBuJU77MTaN0ljMWE47kxGJQ7jY=