simplified flags package

using same logic as flag.Duration

Author: jorinvo

flags/intlist.go

@@ -10,13 +10,13 @@ import (
 type intlist struct {
 	min  int
 	max  int
-	list []int
+	list *[]int
 }
 
 func (l *intlist) String() string {
-	s := make([]string, len(l.list))
-	for i := range l.list {
-		s[i] = strconv.Itoa(l.list[i])
+	s := make([]string, len(*l.list))
+	for i := range *l.list {
+		s[i] = strconv.Itoa((*l.list)[i])
 	}
 	return strings.Join(s, ",")
 }
@@ -34,17 +34,14 @@ func (l *intlist) Set(s string) error {
 		if x > l.max {
 			return fmt.Errorf("%d is bigger than maximum %d", x, l.max)
 		}
-		l.list = append(l.list, x)
+		*l.list = append(*l.list, x)
 	}
 	return nil
 }
 
 // Intlist defines a flag for a comma-separated list of integers.
-// Call the returned function after flag.Parse to get the value.
-func Intlist(name, usage string, min, max int) func() []int {
-	l := &intlist{min: min, max: max}
-	flag.Var(l, name, usage)
-	return func() []int {
-		return l.list
-	}
+func Intlist(name, usage string, min, max int) *[]int {
+	l := &[]int{}
+	flag.Var(&intlist{list: l, min: min, max: max}, name, usage)
+	return l
 }

flags/intlist_test.go

@@ -20,7 +20,7 @@ func TestIntlist(t *testing.T) {
 	}
 
 	for i, tt := range tests {
-		l := intlist{min: 0, max: 10}
+		l := intlist{min: 0, max: 10, list: &[]int{}}
 		if err := l.Set(tt.text); err != nil {
 			if !tt.invalid {
 				t.Errorf("parsing %s failed unexpectedly: %v", tt.text, err)
@@ -31,7 +31,7 @@ func TestIntlist(t *testing.T) {
 			t.Errorf("parsing %s should have failed", tt.text)
 			continue
 		}
-		if !equal(l.list, tt.parsed) {
+		if !equal(*l.list, tt.parsed) {
 			t.Errorf(`
 %d.
 Input:    %s

flags/monthlist.go

@@ -8,14 +8,12 @@ import (
 	"time"
 )
 
-type monthlist struct {
-	list []time.Month
-}
+type monthlist []time.Month
 
 func (l *monthlist) String() string {
-	s := make([]string, len(l.list))
-	for i := range l.list {
-		s[i] = strconv.Itoa(int(l.list[i]))
+	s := make([]string, len(*l))
+	for i := range *l {
+		s[i] = strconv.Itoa(int((*l)[i]))
 	}
 	return strings.Join(s, ",")
 }
@@ -31,18 +29,15 @@ func (l *monthlist) Set(s string) error {
 		if x < 1 || x > 12 {
 			return fmt.Errorf("invalid month: %d", x)
 		}
-		l.list = append(l.list, x)
+		*l = monthlist(append(*l, x))
 	}
 	return nil
 }
 
 // Monthlist defines a flag for a comma-separated list of months.
 // Valid values are between 1 and 12.
-// Call the returned function after flag.Parse to get the value.
-func Monthlist(name, usage string) func() []time.Month {
-	l := &monthlist{}
-	flag.Var(l, name, usage)
-	return func() []time.Month {
-		return l.list
-	}
+func Monthlist(name, usage string) *[]time.Month {
+	l := &[]time.Month{}
+	flag.Var((*monthlist)(l), name, usage)
+	return l
 }

flags/monthlist_test.go

@@ -33,12 +33,12 @@ func TestMonthlist(t *testing.T) {
 			t.Errorf("parsing %s should have failed", tt.text)
 			continue
 		}
-		if !equalMonth(l.list, tt.parsed) {
+		if !equalMonth(l, tt.parsed) {
 			t.Errorf(`
 %d.
 Input:    %s
 Expected: %v
-Got       %v`, i, tt.text, tt.parsed, l.list)
+Got       %v`, i, tt.text, tt.parsed, l)
 		}
 	}
 

flags/weekdaylist.go

@@ -17,14 +17,12 @@ var strDays = map[string]time.Weekday{
 	"su": time.Sunday,
 }
 
-type weekdaylist struct {
-	list []time.Weekday
-}
+type weekdaylist []time.Weekday
 
 func (l *weekdaylist) String() string {
-	s := make([]string, len(l.list))
-	for i := range l.list {
-		s[i] = dayToString(l.list[i])
+	s := make([]string, len(*l))
+	for i := range *l {
+		s[i] = dayToString((*l)[i])
 	}
 	return strings.Join(s, ",")
 }
@@ -45,18 +43,15 @@ func (l *weekdaylist) Set(s string) error {
 		if !ok {
 			return fmt.Errorf("invalid day at index %d: %s", i, d)
 		}
-		l.list = append(l.list, x)
+		*l = weekdaylist(append(*l, x))
 	}
 	return nil
 }
 
 // Weekdaylist defines a flag for a comma-separated list of week days.
 // Valid values are mo, tu, we, th, fr, sa, su.
-// Call the returned function after flag.Parse to get the value.
-func Weekdaylist(name, usage string) func() []time.Weekday {
-	l := &weekdaylist{}
-	flag.Var(l, name, usage)
-	return func() []time.Weekday {
-		return l.list
-	}
+func Weekdaylist(name, usage string) *[]time.Weekday {
+	l := &[]time.Weekday{}
+	flag.Var((*weekdaylist)(l), name, usage)
+	return l
 }

flags/weekdaylist_test.go

@@ -33,12 +33,12 @@ func TestWeekdaylist(t *testing.T) {
 			t.Errorf("parsing %s should have failed", tt.text)
 			continue
 		}
-		if !equalWeekday(l.list, tt.parsed) {
+		if !equalWeekday(l, tt.parsed) {
 			t.Errorf(`
 %d.
 Input:    %s
 Expected: %v
-Got       %v`, i, tt.text, tt.parsed, l.list)
+Got       %v`, i, tt.text, tt.parsed, l)
 		}
 	}
 

main.go

@@ -75,12 +75,12 @@ func main() {
 	now := time.Now()
 
 	next := match.Next(now, match.Condition{
-		Month:   month(),
-		Weekday: weekday(),
-		Day:     day(),
-		Hour:    hour(),
-		Minute:  minute(),
-		Second:  second(),
+		Month:   *month,
+		Weekday: *weekday,
+		Day:     *day,
+		Hour:    *hour,
+		Minute:  *minute,
+		Second:  *second,
 	})
 
 	// No conditions specified