elements.go

package parser

// Element is the interface that all elements implement. It represents an
// abstraction of the different gemtext line types.
//
// Type() returns the type of the element. It can be compared with
// [ElementTypes]:
//
//	func example(e p.Element) {
//		if e.Type() == p.ElementTypes.Text() {
//			// Do something
//		}
//	}
//
// Text() returns any text associated with the element. For [Text], [Heading],
// [List], and [Quote], it returns the main text of the element. For [Link], it
// returns the user-friendly link name. For [PreformatToggle], it returns the
// alt text.
//
// URL() returns a URL associated with the element. Only [Link] actually returns
// a URL, other elements will return an empty string.
//
// Level() returns the heading level associated with the element. Only [Heading]
// actually returns a heading level, other elements will return
// [HeadingLevels].NotHeading(). It can be compared with [HeadingLevels]:
//
//	func example(h p.Heading) {
//		if h.Level() == p.HeadingLevels.Heading() {
//			// Do something
//		}
//	}
type Element interface {
	Type() elementType
	Text() string
	URL() string
	Level() headingLevel
}

var defaultValues = struct {
	url   string
	level headingLevel
}{
	"",
	HeadingLevels.NotHeading(),
}

// Text represents a text line.
type Text struct {
	text string
}

func NewText(text string) Text {
	return Text{text: text}
}
func (t Text) Type() elementType {
	return ElementTypes.text
}
func (t Text) Text() string {
	return t.text
}
func (t Text) URL() string {
	return defaultValues.url
}
func (t Text) Level() headingLevel {
	return defaultValues.level
}

// Link represents a link line.
type Link struct {
	text string
	url  string
}

func NewLink(text string, url string) Link {
	return Link{text: text, url: url}
}
func (l Link) Type() elementType {
	return ElementTypes.link
}
func (l Link) Text() string {
	return l.text
}
func (l Link) URL() string {
	return l.url
}
func (l Link) Level() headingLevel {
	return defaultValues.level
}

// Heading represents a heading line.
type Heading struct {
	text  string
	level headingLevel
}

func NewHeading(text string, level headingLevel) Heading {
	return Heading{text: text, level: level}
}
func (h Heading) Type() elementType {
	return ElementTypes.heading
}
func (h Heading) Text() string {
	return h.text
}
func (h Heading) URL() string {
	return defaultValues.url
}
func (h Heading) Level() headingLevel {
	return h.level
}

// List represents a list item.
type List struct {
	text string
}

func NewList(text string) List {
	return List{text: text}
}
func (l List) Type() elementType {
	return ElementTypes.list
}
func (l List) Text() string {
	return l.text
}
func (l List) URL() string {
	return defaultValues.url
}
func (l List) Level() headingLevel {
	return defaultValues.level
}

// Quote represents a quote line.
type Quote struct {
	text string
}

func NewQuote(text string) Quote {
	return Quote{text: text}
}
func (q Quote) Type() elementType {
	return ElementTypes.quote
}
func (q Quote) Text() string {
	return q.text
}
func (q Quote) URL() string {
	return defaultValues.url
}
func (q Quote) Level() headingLevel {
	return defaultValues.level
}

// PreformatToggle represents a preformat toggle line.
type PreformatToggle struct {
	text string
}

func NewPreformatToggle(text string) PreformatToggle {
	return PreformatToggle{text: text}
}
func (pt PreformatToggle) Type() elementType {
	return ElementTypes.preformatToggle
}
func (pt PreformatToggle) Text() string {
	return pt.text
}
func (pt PreformatToggle) URL() string {
	return defaultValues.url
}
func (pt PreformatToggle) Level() headingLevel {
	return defaultValues.level
}