Change to variadic int args in Slicestr

Makes for a better template api.

2 files changed, 23 insertions, 21 deletions

diff --git a/tpl/template.go b/tpl/template.go
index 89c522a4f..c94f65725 100644
--- a/tpl/template.go
+++ b/tpl/template.go
@@ -190,22 +190,23 @@ func compareGetFloat(a interface{}, b interface{}) (float64, float64) {
 
 // Slicing in Slicestr is done by specifying a half-open range with
 // two indices, start and end. 1 and 4 creates a slice including elements 1 through 3.
-// The start and/or end indices can be omitted by setting one or both of them to -1;
-// they default to zero and the slice's length respectively
-func Slicestr(a interface{}, start, end int) (string, error) {
+// The end index can be omitted, it defaults to the string's length.
+func Slicestr(a interface{}, startEnd ...int) (string, error) {
 	aStr, err := cast.ToStringE(a)
 	if err != nil {
 		return "", err
 	}
 
-	if start != -1 && end != -1 {
-		return aStr[start:end], nil
-	} else if start == -1 && end == -1 {
-		return aStr[:], nil
-	} else if start == -1 {
-		return aStr[:end], nil
+	if len(startEnd) > 2 {
+		return "", errors.New("too many arguments")
+	}
+
+	if len(startEnd) == 2 {
+		return aStr[startEnd[0]:startEnd[1]], nil
+	} else if len(startEnd) == 1 {
+		return aStr[startEnd[0]:], nil
 	} else {
-		return aStr[start:], nil
+		return aStr[:], nil
 	}
 
 }
diff --git a/tpl/template_test.go b/tpl/template_test.go
index b3764e737..20a887b1c 100644
--- a/tpl/template_test.go
+++ b/tpl/template_test.go
@@ -279,20 +279,21 @@ func TestIn(t *testing.T) {
 func TestSlicestr(t *testing.T) {
 	for i, this := range []struct {
 		v1     interface{}
-		v2     int
-		v3     int
+		v2     []int
 		expect interface{}
 	}{
-		{"abc", 1, 2, "b"},
-		{"abc", 1, 3, "bc"},
-		{"abc", 0, 1, "a"},
-		{"abcdef", -1, -1, "abcdef"},
-		{"abcdef", -1, 2, "ab"},
-		{"abcdef", 2, -1, "cdef"},
-		{123, 1, 3, "23"},
-		{tstNoStringer{}, 0, 1, false},
+		{"abc", []int{1, 2}, "b"},
+		{"abc", []int{1, 3}, "bc"},
+		{"abc", []int{0, 1}, "a"},
+		{"abcdef", []int{}, "abcdef"},
+		{"abcdef", []int{0, 6}, "abcdef"},
+		{"abcdef", []int{0, 2}, "ab"},
+		{"abcdef", []int{2}, "cdef"},
+		{123, []int{1, 3}, "23"},
+		{123, []int{1, 2, 3}, false},
+		{tstNoStringer{}, []int{0, 1}, false},
 	} {
-		result, err := Slicestr(this.v1, this.v2, this.v3)
+		result, err := Slicestr(this.v1, this.v2...)
 
 		if b, ok := this.expect.(bool); ok && !b {
 			if err == nil {