types(chore) document tag

types/tag.go

@@ -25,12 +25,16 @@ var (
 	ErrTagInvalidCollor = errors.New("tag has invalid color")
 )
 
+// A Tag is a simple structure used to categorize products.
+// Tag names are unique. Tag colors are base 10 RGB notation.
 type Tag struct {
 	Id    uint   `json:"id"`
 	Name  string `json:"name"`
 	Color uint   `json:"color"`
 }
 
+// GenerateColor generates a random tag color using the tag's
+// name's SHA1.
 func (t *Tag) GenerateColor() error {
 	if t.Name == "" {
 		return ErrTagNameEmpty
@@ -45,6 +49,7 @@ func (t *Tag) GenerateColor() error {
 	return nil
 }
 
+// RGB converts the base 10 RGB color in an array of color values.
 func (t *Tag) RGB() ([]uint, error) {
 	if !t.ValidColor() {
 		return nil, ErrTagInvalidCollor
@@ -60,14 +65,19 @@ func (t *Tag) RGB() ([]uint, error) {
 	return colors, nil
 }
 
+// ValidColor verifies that the tag's color is valid.
 func (t *Tag) ValidColor() bool {
 	return t.Color < colorRage
 }
 
+// ValidName verifies that the tag has a name.
+// Uniqueness verification is the data source's job.
 func (t *Tag) ValidName() bool {
 	return t.Name != ""
 }
 
+// Valid verifies that the tag is valid.
+// A valid tag has a valid color and a name.
 func (t *Tag) Valid() bool {
 	return t.ValidColor() && t.ValidName()
 }