Parsetag

parsetag.go

@@ -0,0 +1,36 @@
+package reflectutils
+
+import (
+	"reflect"
+	"regexp"
+)
+
+var aTagRE = regexp.MustCompile(`(\S+):"((?:[^"\\]|\\.)*)"(?:\s+|$)`)
+
+type Tag struct {
+	Tag   string
+	Value string
+}
+
+// SplitTag breaks apart a reflect.StructTag into an array of key/value pairs.
+func SplitTag(tag reflect.StructTag) []Tag {
+	found := make([]Tag, 0, 5)
+	s := string(tag)
+	for len(s) > 0 {
+		f := aTagRE.FindStringSubmatchIndex(s)
+		if len(f) != 6 {
+			break
+		}
+		tag := s[f[2]:f[3]]
+		value := s[f[4]:f[5]]
+		found = append(found, Tag{
+			Tag:   tag,
+			Value: value,
+		})
+		s = s[f[1]:]
+	}
+	if len(found) == 0 {
+		return nil
+	}
+	return found
+}

parsetag_test.go

@@ -0,0 +1,31 @@
+package reflectutils_test
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/muir/reflectutils"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSplitTag(t *testing.T) {
+	ts(t, `env:"foo"`, "env", "foo")
+	ts(t, `env:"YO"  flag:"foo,bar"`, "env", "YO", "flag", "foo,bar")
+	ts(t, ``)
+	ts(t, `env:"YO"  flag:"foo\",bar"`, "env", "YO", "flag", `foo\",bar`)
+	ts(t, `env:"YO"  flag:"foo,bar" `, "env", "YO", "flag", "foo,bar")
+}
+
+func ts(t *testing.T, tag reflect.StructTag, want ...string) {
+	t.Log(tag)
+	tags := reflectutils.SplitTag(tag)
+	s := make([]string, 0, len(tags)*2)
+	if len(tags) == 0 {
+		s = nil
+	}
+	for _, tag := range tags {
+		s = append(s, tag.Tag, tag.Value)
+	}
+	assert.Equal(t, want, s, tag)
+}