337 lines
9 KiB
Go
337 lines
9 KiB
Go
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package extension
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import (
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"bytes"
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"github.com/yuin/goldmark"
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gast "github.com/yuin/goldmark/ast"
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"github.com/yuin/goldmark/extension/ast"
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"github.com/yuin/goldmark/parser"
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"github.com/yuin/goldmark/renderer"
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"github.com/yuin/goldmark/renderer/html"
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"github.com/yuin/goldmark/text"
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"github.com/yuin/goldmark/util"
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"strconv"
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)
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var footnoteListKey = parser.NewContextKey()
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type footnoteBlockParser struct {
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}
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var defaultFootnoteBlockParser = &footnoteBlockParser{}
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// NewFootnoteBlockParser returns a new parser.BlockParser that can parse
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// footnotes of the Markdown(PHP Markdown Extra) text.
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func NewFootnoteBlockParser() parser.BlockParser {
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return defaultFootnoteBlockParser
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}
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func (b *footnoteBlockParser) Trigger() []byte {
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return []byte{'['}
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}
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func (b *footnoteBlockParser) Open(parent gast.Node, reader text.Reader, pc parser.Context) (gast.Node, parser.State) {
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line, segment := reader.PeekLine()
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pos := pc.BlockOffset()
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if pos < 0 || line[pos] != '[' {
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return nil, parser.NoChildren
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}
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pos++
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if pos > len(line)-1 || line[pos] != '^' {
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return nil, parser.NoChildren
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}
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open := pos + 1
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closes := 0
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closure := util.FindClosure(line[pos+1:], '[', ']', false, false)
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closes = pos + 1 + closure
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next := closes + 1
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if closure > -1 {
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if next >= len(line) || line[next] != ':' {
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return nil, parser.NoChildren
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}
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} else {
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return nil, parser.NoChildren
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}
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padding := segment.Padding
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label := reader.Value(text.NewSegment(segment.Start+open-padding, segment.Start+closes-padding))
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if util.IsBlank(label) {
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return nil, parser.NoChildren
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}
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item := ast.NewFootnote(label)
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pos = next + 1 - padding
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if pos >= len(line) {
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reader.Advance(pos)
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return item, parser.NoChildren
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}
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reader.AdvanceAndSetPadding(pos, padding)
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return item, parser.HasChildren
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}
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func (b *footnoteBlockParser) Continue(node gast.Node, reader text.Reader, pc parser.Context) parser.State {
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line, _ := reader.PeekLine()
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if util.IsBlank(line) {
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return parser.Continue | parser.HasChildren
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}
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childpos, padding := util.IndentPosition(line, reader.LineOffset(), 4)
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if childpos < 0 {
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return parser.Close
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}
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reader.AdvanceAndSetPadding(childpos, padding)
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return parser.Continue | parser.HasChildren
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}
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func (b *footnoteBlockParser) Close(node gast.Node, reader text.Reader, pc parser.Context) {
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var list *ast.FootnoteList
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if tlist := pc.Get(footnoteListKey); tlist != nil {
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list = tlist.(*ast.FootnoteList)
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} else {
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list = ast.NewFootnoteList()
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pc.Set(footnoteListKey, list)
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node.Parent().InsertBefore(node.Parent(), node, list)
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}
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node.Parent().RemoveChild(node.Parent(), node)
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list.AppendChild(list, node)
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}
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func (b *footnoteBlockParser) CanInterruptParagraph() bool {
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return true
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}
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func (b *footnoteBlockParser) CanAcceptIndentedLine() bool {
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return false
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}
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type footnoteParser struct {
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}
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var defaultFootnoteParser = &footnoteParser{}
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// NewFootnoteParser returns a new parser.InlineParser that can parse
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// footnote links of the Markdown(PHP Markdown Extra) text.
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func NewFootnoteParser() parser.InlineParser {
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return defaultFootnoteParser
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}
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func (s *footnoteParser) Trigger() []byte {
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// footnote syntax probably conflict with the image syntax.
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// So we need trigger this parser with '!'.
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return []byte{'!', '['}
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}
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func (s *footnoteParser) Parse(parent gast.Node, block text.Reader, pc parser.Context) gast.Node {
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line, segment := block.PeekLine()
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pos := 1
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if len(line) > 0 && line[0] == '!' {
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pos++
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}
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if pos >= len(line) || line[pos] != '^' {
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return nil
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}
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pos++
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if pos >= len(line) {
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return nil
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}
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open := pos
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closure := util.FindClosure(line[pos:], '[', ']', false, false)
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if closure < 0 {
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return nil
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}
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closes := pos + closure
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value := block.Value(text.NewSegment(segment.Start+open, segment.Start+closes))
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block.Advance(closes + 1)
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var list *ast.FootnoteList
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if tlist := pc.Get(footnoteListKey); tlist != nil {
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list = tlist.(*ast.FootnoteList)
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}
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if list == nil {
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return nil
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}
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index := 0
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for def := list.FirstChild(); def != nil; def = def.NextSibling() {
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d := def.(*ast.Footnote)
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if bytes.Equal(d.Ref, value) {
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if d.Index < 0 {
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list.Count += 1
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d.Index = list.Count
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}
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index = d.Index
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break
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}
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}
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if index == 0 {
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return nil
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}
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return ast.NewFootnoteLink(index)
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}
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type footnoteASTTransformer struct {
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}
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var defaultFootnoteASTTransformer = &footnoteASTTransformer{}
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// NewFootnoteASTTransformer returns a new parser.ASTTransformer that
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// insert a footnote list to the last of the document.
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func NewFootnoteASTTransformer() parser.ASTTransformer {
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return defaultFootnoteASTTransformer
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}
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func (a *footnoteASTTransformer) Transform(node *gast.Document, reader text.Reader, pc parser.Context) {
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var list *ast.FootnoteList
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if tlist := pc.Get(footnoteListKey); tlist != nil {
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list = tlist.(*ast.FootnoteList)
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} else {
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return
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}
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pc.Set(footnoteListKey, nil)
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for footnote := list.FirstChild(); footnote != nil; {
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var container gast.Node = footnote
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next := footnote.NextSibling()
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if fc := container.LastChild(); fc != nil && gast.IsParagraph(fc) {
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container = fc
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}
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index := footnote.(*ast.Footnote).Index
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if index < 0 {
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list.RemoveChild(list, footnote)
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} else {
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container.AppendChild(container, ast.NewFootnoteBackLink(index))
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}
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footnote = next
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}
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list.SortChildren(func(n1, n2 gast.Node) int {
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if n1.(*ast.Footnote).Index < n2.(*ast.Footnote).Index {
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return -1
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}
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return 1
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})
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if list.Count <= 0 {
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list.Parent().RemoveChild(list.Parent(), list)
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return
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}
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node.AppendChild(node, list)
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}
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// FootnoteHTMLRenderer is a renderer.NodeRenderer implementation that
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// renders FootnoteLink nodes.
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type FootnoteHTMLRenderer struct {
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html.Config
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}
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// NewFootnoteHTMLRenderer returns a new FootnoteHTMLRenderer.
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func NewFootnoteHTMLRenderer(opts ...html.Option) renderer.NodeRenderer {
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r := &FootnoteHTMLRenderer{
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Config: html.NewConfig(),
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}
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for _, opt := range opts {
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opt.SetHTMLOption(&r.Config)
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}
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return r
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}
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// RegisterFuncs implements renderer.NodeRenderer.RegisterFuncs.
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func (r *FootnoteHTMLRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
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reg.Register(ast.KindFootnoteLink, r.renderFootnoteLink)
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reg.Register(ast.KindFootnoteBackLink, r.renderFootnoteBackLink)
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reg.Register(ast.KindFootnote, r.renderFootnote)
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reg.Register(ast.KindFootnoteList, r.renderFootnoteList)
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}
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func (r *FootnoteHTMLRenderer) renderFootnoteLink(w util.BufWriter, source []byte, node gast.Node, entering bool) (gast.WalkStatus, error) {
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if entering {
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n := node.(*ast.FootnoteLink)
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is := strconv.Itoa(n.Index)
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_, _ = w.WriteString(`<sup id="fnref:`)
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_, _ = w.WriteString(is)
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_, _ = w.WriteString(`"><a href="#fn:`)
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_, _ = w.WriteString(is)
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_, _ = w.WriteString(`" class="footnote-ref" role="doc-noteref">`)
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_, _ = w.WriteString(is)
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_, _ = w.WriteString(`</a></sup>`)
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}
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return gast.WalkContinue, nil
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}
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func (r *FootnoteHTMLRenderer) renderFootnoteBackLink(w util.BufWriter, source []byte, node gast.Node, entering bool) (gast.WalkStatus, error) {
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if entering {
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n := node.(*ast.FootnoteBackLink)
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is := strconv.Itoa(n.Index)
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_, _ = w.WriteString(` <a href="#fnref:`)
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_, _ = w.WriteString(is)
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_, _ = w.WriteString(`" class="footnote-backref" role="doc-backlink">`)
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_, _ = w.WriteString("↩︎")
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_, _ = w.WriteString(`</a>`)
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}
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return gast.WalkContinue, nil
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}
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func (r *FootnoteHTMLRenderer) renderFootnote(w util.BufWriter, source []byte, node gast.Node, entering bool) (gast.WalkStatus, error) {
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n := node.(*ast.Footnote)
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is := strconv.Itoa(n.Index)
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if entering {
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_, _ = w.WriteString(`<li id="fn:`)
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_, _ = w.WriteString(is)
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_, _ = w.WriteString(`" role="doc-endnote"`)
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if node.Attributes() != nil {
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html.RenderAttributes(w, node, html.ListItemAttributeFilter)
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}
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_, _ = w.WriteString(">\n")
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} else {
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_, _ = w.WriteString("</li>\n")
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}
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return gast.WalkContinue, nil
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}
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func (r *FootnoteHTMLRenderer) renderFootnoteList(w util.BufWriter, source []byte, node gast.Node, entering bool) (gast.WalkStatus, error) {
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tag := "section"
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if r.Config.XHTML {
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tag = "div"
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}
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if entering {
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_, _ = w.WriteString("<")
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_, _ = w.WriteString(tag)
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_, _ = w.WriteString(` class="footnotes" role="doc-endnotes"`)
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if node.Attributes() != nil {
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html.RenderAttributes(w, node, html.GlobalAttributeFilter)
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}
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_ = w.WriteByte('>')
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if r.Config.XHTML {
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_, _ = w.WriteString("\n<hr />\n")
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} else {
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_, _ = w.WriteString("\n<hr>\n")
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}
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_, _ = w.WriteString("<ol>\n")
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} else {
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_, _ = w.WriteString("</ol>\n")
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_, _ = w.WriteString("</")
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_, _ = w.WriteString(tag)
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_, _ = w.WriteString(">\n")
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}
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return gast.WalkContinue, nil
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}
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type footnote struct {
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}
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// Footnote is an extension that allow you to use PHP Markdown Extra Footnotes.
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var Footnote = &footnote{}
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func (e *footnote) Extend(m goldmark.Markdown) {
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m.Parser().AddOptions(
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parser.WithBlockParsers(
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util.Prioritized(NewFootnoteBlockParser(), 999),
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),
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parser.WithInlineParsers(
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util.Prioritized(NewFootnoteParser(), 101),
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),
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parser.WithASTTransformers(
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util.Prioritized(NewFootnoteASTTransformer(), 999),
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),
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)
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m.Renderer().AddOptions(renderer.WithNodeRenderers(
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util.Prioritized(NewFootnoteHTMLRenderer(), 500),
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))
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}
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