Rename Substr to Slice

That is whas was implemented, not Substr.

Also make the API more similar to Go's internal slice by making both the start and end indices optional.

See #990

diff --git a/tpl/template.go b/tpl/template.go
index 7e9f41f1f66c622e7d917ae36728e288f243e09c..1f899faf736b0291ee9a5eb6749cea32ec83b19d 100644 (file)
--- a/tpl/template.go
+++ b/tpl/template.go
@@ -188,12 +188,25 @@ func compareGetFloat(a interface{}, b interface{}) (float64, float64) {
        return left, right
 }
 
-func Substr(a interface{}, pos, length int) (string, error) {
+// Slicing in Slice is done by specifying a half-open range with
+// two indices, lower and upper. 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 Slice(a interface{}, start, end int) (string, error) {
        aStr, err := cast.ToStringE(a)
        if err != nil {
                return "", err
        }
-       return aStr[pos:length], nil
+
+       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
+       } else {
+               return aStr[start:], nil
+       }
+
 }
 
 func Split(a interface{}, delimiter string) ([]string, error) {
@@ -1324,7 +1337,7 @@ func init() {
                "lt":          Lt,
                "le":          Le,
                "in":          In,
-               "substr":      Substr,
+               "slice":       Slice,
                "split":       Split,
                "intersect":   Intersect,
                "isSet":       IsSet,

diff --git a/tpl/template_test.go b/tpl/template_test.go
index dca4711d16480d8bd4055bb2b35ab221bd3c4b8b..55f739576a5368cd07519e67fab97e3d7c25468b 100644 (file)
--- a/tpl/template_test.go
+++ b/tpl/template_test.go
@@ -276,7 +276,7 @@ func TestIn(t *testing.T) {
        }
 }
 
-func TestSubstr(t *testing.T) {
+func TestSlice(t *testing.T) {
        for i, this := range []struct {
                v1     interface{}
                v2     int
@@ -286,14 +286,17 @@ func TestSubstr(t *testing.T) {
                {"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},
        } {
-               result, err := Substr(this.v1, this.v2, this.v3)
+               result, err := Slice(this.v1, this.v2, this.v3)
 
                if b, ok := this.expect.(bool); ok && !b {
                        if err == nil {
-                               t.Errorf("[%d] Substr didn't return an expected error", i)
+                               t.Errorf("[%d] Slice didn't return an expected error", i)
                        }
                } else {
                        if err != nil {