Change readme accordingly

README.md

@@ -15,8 +15,8 @@ go get git.streifling.com/jason/atom@latest
 ## Usage
 
 This library provides convenient functions to safely create and extend elements
-and attributes of an Atom feed. This is because it can be hard to know all
-pitfalls of RFC4287. The intended way of using atom is with these functions.
+and attributes of Atom feeds. It also provides checks for all constructs'
+adherence to RFC4287.
 
 ```go
 package main
@@ -29,30 +29,28 @@ import (
 )
 
 func main() {
- feed, err := atom.NewFeed("Example Feed")
- if err != nil {
+ feed := atom.NewFeed("Example Feed")
+ feed.Title = atom.NewText("text", "Example Feed")
+ feed.ID = atom.NewID(atom.NewURN())
+ if err := feed.Check(); err != nil {
   log.Fatalln(err)
  }
 
  author := atom.NewPerson("John Doe")
  author.Email = "john.doe@example.com"
+ if err := author.Check(); err != nil {
+  log.Fatalln(err)
+ }
  feed.AddAuthor(author)
 
- entry, err := atom.NewEntry("First Entry")
- if err != nil {
+ entry := atom.NewEntry("First Entry")
+ entry.ID = atom.NewID(atom.NewURN())
+ entry.Content = atom.NewContent(atom.InlineText, "text", "This is the content of the first entry.")
+ if err := entry.Check(); err != nil {
   log.Fatalln(err)
  }
- content, err := atom.NewContent(atom.InlineText, "text", "This is the content of the first entry.")
- if err != nil {
-  log.Fatalln(err)
- }
- entry.Content = content
  feed.AddEntry(entry)
 
- if err := feed.Check(); err != nil {
-  log.Fatalln(err)
- }
-
  feedString, err := feed.ToXML("utf-8")
  if err != nil {
   log.Fatalln(err)
@@ -62,7 +60,7 @@ func main() {
 ```
 
 It is also possible to use this library in a way similar to what other libraries
-would provide. This is, of course, making it easier to make mistakes.
+provide.
 
 ```go
 package main
@@ -115,7 +113,7 @@ func main() {
 }
 ```
 
-The output of both ways of using it is an RFC4287 compliant Atom feed:
+The output of both ways of using it is an RFC4287 compliant Atom feed.
 
 ```xml
 <?xml version="1.0" encoding="utf-8"?>

atom.go

@@ -11,10 +11,6 @@ import (
 	"golang.org/x/text/language"
 )
 
-func Unescape(s string) string {
-	return html.UnescapeString(s)
-}
-
 // isValidIRI checks whether an IRI is valid or not. It returns a bool.
 // https://www.w3.org/2011/04/XMLSchema/TypeLibrary-IRI-RFC3987.xsd
 func isValidIRI(iri string) bool {
@@ -22,15 +18,6 @@ func isValidIRI(iri string) bool {
 	return regexp.MustCompile(pattern).MatchString(iri)
 }
 
-// NewIRI creates a new IRI. It returns a string and an error.
-func NewIRI(iri string) (string, error) {
-	if !isValidIRI(iri) {
-		return "", fmt.Errorf("iri %v not correctly formatted", iri)
-	}
-
-	return iri, nil
-}
-
 // isCorrectlyEscaped checks whether a string is correctly escaped as per
 // RFC4287. It returns a bool.
 func isCorrectlyEscaped(text string) bool {
@@ -83,31 +70,12 @@ func isValidMediaType(m string) bool {
 	return true
 }
 
-// NewMediaType creates a new MediaType. It returns a string and an error.
-func NewMediaType(m string) (string, error) {
-	if !isValidMediaType(m) {
-		return "", fmt.Errorf("media type %v invalid", m)
-	}
-
-	mediaType, _, _ := mime.ParseMediaType(m)
-	return mediaType, nil
-}
-
 // isValidLanguageTag checks whether a LanguageTag is valid. It returns a bool.
 func isValidLanguageTag(languageTag string) bool {
 	_, err := language.Parse(languageTag)
 	return err == nil
 }
 
-// NewLanguageTag creates a new LanguageTag. It returns a string and an error.
-func NewLanguageTag(l string) (string, error) {
-	if !isValidLanguageTag(l) {
-		return "", fmt.Errorf("language tag %v invalid", l)
-	}
-
-	return l, nil
-}
-
 // isValidAttribute checks whether an Attribute is valid. It returns a bool.
 func isValidAttribute(attribute string) bool {
 	regex := regexp.MustCompile(`^[a-zA-Z0-9_]+="[^"]*"$`)
@@ -118,3 +86,8 @@ func isValidAttribute(attribute string) bool {
 func NewURN() string {
 	return fmt.Sprint("urn:uuid:", uuid.New())
 }
+
+// Unescape unescapes a string. It returns an IRI.
+func Unescape(s string) string {
+	return html.UnescapeString(s)
+}

category.go

@@ -15,7 +15,10 @@ type Category struct {
 
 // NewCategory creates a new Category. It returns a *Category.
 func NewCategory(term string) *Category {
-	return &Category{Term: term}
+	return &Category{
+		CommonAttributes: newCommonAttributes(),
+		Term:             term,
+	}
 }
 
 // SetLabel sets the Label attribute of the Category.

commonAttributes.go

@@ -13,7 +13,7 @@ type CommonAttributes struct {
 
 // NewCommonAttributes creates a new set of CommonAttributes. It returns a
 // *CommonAttributes.
-func NewCommonAttributes() *CommonAttributes {
+func newCommonAttributes() *CommonAttributes {
 	return new(CommonAttributes)
 }
 

date.go

@@ -18,7 +18,10 @@ func DateTime(t time.Time) string {
 
 // NewDate creates a new Date. It returns a *Date.
 func NewDate(t time.Time) *Date {
-	return &Date{DateTime: DateTime(t)}
+	return &Date{
+		CommonAttributes: newCommonAttributes(),
+		DateTime:         DateTime(t),
+	}
 }
 
 // Check checks the Date for incompatibilities with RFC4287. It returns an

entry.go

@@ -59,9 +59,10 @@ func (e *Entry) checkAuthors(authorInFeed bool) error {
 // NewEntry creates a new Entry. It returns a *Entry.
 func NewEntry(title string) *Entry {
 	return &Entry{
-		ID:      NewID(NewURN()),
-		Title:   NewText("text", title),
-		Updated: NewDate(time.Now()),
+		CommonAttributes: newCommonAttributes(),
+		ID:               NewID(NewURN()),
+		Title:            NewText("text", title),
+		Updated:          NewDate(time.Now()),
 	}
 }
 

feed.go

@@ -28,9 +28,10 @@ type Feed struct {
 // NewFeed creates a new Feed. It returns a *Feed.
 func NewFeed(title string) *Feed {
 	return &Feed{
-		ID:      NewID(NewURN()),
-		Title:   NewText("text", title),
-		Updated: NewDate(time.Now()),
+		CommonAttributes: newCommonAttributes(),
+		ID:               NewID(NewURN()),
+		Title:            NewText("text", title),
+		Updated:          NewDate(time.Now()),
 	}
 }
 

generator.go

@@ -16,7 +16,10 @@ type Generator struct {
 
 // NewGenerator creates a new Generator. It returns a *Generator.
 func NewGenerator(text string) *Generator {
-	return &Generator{Text: html.UnescapeString(text)}
+	return &Generator{
+		CommonAttributes: newCommonAttributes(),
+		Text:             html.UnescapeString(text),
+	}
 }
 
 // Check checks the Generator for incompatibilities with RFC4287. It returns an

icon.go

@@ -14,7 +14,10 @@ type Icon struct {
 
 // NewIcon creates a new Icon. It returns a *Icon.
 func NewIcon(uri string) *Icon {
-	return &Icon{URI: uri}
+	return &Icon{
+		CommonAttributes: newCommonAttributes(),
+		URI:              uri,
+	}
 }
 
 // Check checks the Icon for incompatibilities with RFC4287. It returns an

id.go

@@ -14,7 +14,10 @@ type ID struct {
 
 // NewID creates a new ID. It returns a *ID.
 func NewID(uri string) *ID {
-	return &ID{URI: uri}
+	return &ID{
+		CommonAttributes: newCommonAttributes(),
+		URI:              uri,
+	}
 }
 
 // Check checks the ID for incompatibilities with RFC4287. It returns an error.

inlineOtherContent.go

@@ -17,7 +17,12 @@ type InlineOtherContent struct {
 // *InlineOtherContent and an error.
 func newInlineOtherContent(mediaType string, content any) *InlineOtherContent {
 	mediaType, _, _ = mime.ParseMediaType(mediaType)
-	return &InlineOtherContent{Type: mediaType, AnyElement: content}
+
+	return &InlineOtherContent{
+		CommonAttributes: newCommonAttributes(),
+		Type:             mediaType,
+		AnyElement:       content,
+	}
 }
 
 // isContent checks whether the InlineOtherContent is a Content. It returns a

inlineTextContent.go

@@ -15,7 +15,11 @@ type InlineTextContent struct {
 // newInlineTextContent creates a new InlineTextContent. It returns a
 // *InlineTextContent.
 func newInlineTextContent(mediaType, text string) *InlineTextContent {
-	return &InlineTextContent{Type: mediaType, Text: text}
+	return &InlineTextContent{
+		CommonAttributes: newCommonAttributes(),
+		Type:             mediaType,
+		Text:             text,
+	}
 }
 
 // isContent checks whether the InlineTextContent is a Content. It returns a

inlineXHTMLContent.go

@@ -15,7 +15,11 @@ type InlineXHTMLContent struct {
 // newInlineXHTMLContent creates a new InlineXHTMLContent. It returns a
 // *InlineXHTMLContent.
 func newInlineXHTMLContent(mediaType string, div *XHTMLDiv) *InlineXHTMLContent {
-	return &InlineXHTMLContent{Type: mediaType, XHTMLDiv: div}
+	return &InlineXHTMLContent{
+		CommonAttributes: newCommonAttributes(),
+		Type:             mediaType,
+		XHTMLDiv:         div,
+	}
 }
 
 // isContent checks whether the InlineXHTMLContent is a Content. It returns a

link.go

@@ -19,7 +19,10 @@ type Link struct {
 
 // NewLink creates a new Link. It returns a *Link.
 func NewLink(href string) *Link {
-	return &Link{Href: href}
+	return &Link{
+		CommonAttributes: newCommonAttributes(),
+		Href:             href,
+	}
 }
 
 // Check checks the Link for incompatibilities with RFC4287. It returns an

logo.go

@@ -13,7 +13,10 @@ type Logo struct {
 
 // NewLogo creates a new Logo. It returns a *Logo.
 func NewLogo(uri string) *Logo {
-	return &Logo{URI: uri}
+	return &Logo{
+		CommonAttributes: newCommonAttributes(),
+		URI:              uri,
+	}
 }
 
 // Check checks the Logo for incompatibilities with RFC4287. It returns an

outOfLineContent.go

@@ -17,7 +17,12 @@ type OutOfLineContent struct {
 // *OutOfLineContent.
 func newOutOfLineContent(mediaType, src string) *OutOfLineContent {
 	mediaType, _, _ = mime.ParseMediaType(mediaType)
-	return &OutOfLineContent{Type: mediaType, SRC: src}
+
+	return &OutOfLineContent{
+		CommonAttributes: newCommonAttributes(),
+		Type:             mediaType,
+		SRC:              src,
+	}
 }
 
 // isContent checks whether the OutOfLineContent is a Content. It returns a

person.go

@@ -15,7 +15,10 @@ type Person struct {
 
 // NewPerson creates a new Person. It returns a *Person.
 func NewPerson(name string) *Person {
-	return &Person{Name: name}
+	return &Person{
+		CommonAttributes: newCommonAttributes(),
+		Name:             name,
+	}
 }
 
 // AddExtension adds the Extension to the Person.

plainText.go

@@ -15,7 +15,11 @@ func (p *PlainText) isText() bool { return true }
 
 // newPlainText creates a new PlainText. It returns a *PlainText.
 func newPlainText(textType, content string) *PlainText {
-	return &PlainText{Type: textType, Text: content}
+	return &PlainText{
+		CommonAttributes: newCommonAttributes(),
+		Type:             textType,
+		Text:             content,
+	}
 }
 
 // Check checks the PlainText for incompatibilities with RFC4287. It returns an

source.go

@@ -25,7 +25,7 @@ type Source struct {
 
 // NewSource creates a new Source. It returns a *Source.
 func NewSource() *Source {
-	return new(Source)
+	return &Source{CommonAttributes: newCommonAttributes()}
 }
 
 // Check checks the Source for incompatibilities with RFC4287. It returns an

xhtmlText.go

@@ -16,8 +16,9 @@ func (x *XHTMLText) isText() bool { return true }
 // newPlainText creates a new PlainText. It returns a *PlainText.
 func newXHTMLText(textType, content string) *XHTMLText {
 	return &XHTMLText{
-		Type:     textType,
-		XHTMLDiv: NewXHTMLDiv(content),
+		CommonAttributes: newCommonAttributes(),
+		Type:             textType,
+		XHTMLDiv:         NewXHTMLDiv(content),
 	}
 }