Delete extensionAttribute.go and simplify undefined attributes

commonAttributes.go

@@ -3,9 +3,9 @@ package atom
 import "fmt"
 
 type CommonAttributes struct {
-	Base                IRI                   `xml:"base,attr,omitempty"`
-	Lang                LanguageTag           `xml:"lang,attr,omitempty"`
-	UndefinedAttributes []*ExtensionAttribute `xml:",any"`
+	Base                IRI         `xml:"base,attr,omitempty"`
+	Lang                LanguageTag `xml:"lang,attr,omitempty"`
+	UndefinedAttributes []string    `xml:",attr"`
 }
 
 // NewCommonAttributes creates a new set of CommonAttributes. It returns a
@@ -15,21 +15,21 @@ func NewCommonAttributes() *CommonAttributes {
 }
 
 // AddExtensionAttribute adds the ExtensionAttribute to the CommonAttributes.
-func (c *CommonAttributes) AddExtensionAttribute(e *ExtensionAttribute) {
+func (c *CommonAttributes) AddExtensionAttribute(name, value string) {
 	if c.UndefinedAttributes == nil {
-		c.UndefinedAttributes = make([]*ExtensionAttribute, 1)
-		c.UndefinedAttributes[0] = e
+		c.UndefinedAttributes = make([]string, 1)
+		c.UndefinedAttributes[0] = fmt.Sprint(name, `="`, value, `"`)
 	} else {
-		c.UndefinedAttributes = append(c.UndefinedAttributes, e)
+		c.UndefinedAttributes = append(c.UndefinedAttributes, fmt.Sprint(name, `="`, value, `"`))
 	}
 }
 
 // Check checks the CommonAttributes for incompatibilities with RFC4287. It
 // returns an error.
 func (c *CommonAttributes) Check() error {
-	for i, e := range c.UndefinedAttributes {
-		if err := e.Check(); err != nil {
-			return fmt.Errorf("extension attribute %v of common attributes: %v", i, err)
+	for _, a := range c.UndefinedAttributes {
+		if !isValidAttribute(a) {
+			return fmt.Errorf("attribute %v of undefined attributes of common attributes not correctly formatted", a)
 		}
 	}