feat(reflectx): is a valid tag

reflectx/tags.go

@@ -1,6 +1,11 @@
 package reflectx
 
-import "strings"
+import (
+	"strings"
+	"unicode"
+
+	"github.com/zeiss/pkg/utilx"
+)
 
 // TagOptions ...
 type TagOptions string
@@ -11,3 +16,23 @@ func ParseTag(tag string) (string, TagOptions) {
 	tag, opt, _ := strings.Cut(tag, ",")
 	return tag, TagOptions(opt)
 }
+
+// IsValidTag returns true if the tag is not empty.
+func IsValidTag(tag string) bool {
+	if utilx.Empty(tag) {
+		return false
+	}
+
+	for _, c := range tag {
+		switch {
+		case strings.ContainsRune("!#$%&()*+-./:;<=>?@[]^_{|}~ ", c):
+			// Backslash and quote chars are reserved, but
+			// otherwise any punctuation chars are allowed
+			// in a tag name.
+		case !unicode.IsLetter(c) && !unicode.IsDigit(c):
+			return false
+		}
+	}
+
+	return true
+}

reflectx/tags_test.go

@@ -38,3 +38,25 @@ func TestParseTag(t *testing.T) {
 		assert.Equal(t, test.expectedOptions, opt)
 	}
 }
+
+func TestIsValidTag(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		tag      string
+		expected bool
+	}{
+		{
+			tag:      "name",
+			expected: true,
+		},
+		{
+			tag:      "",
+			expected: false,
+		},
+	}
+
+	for _, test := range tests {
+		assert.Equal(t, test.expected, reflectx.IsValidTag(test.tag))
+	}
+}