Fixes #50

ast/ast.go

@@ -98,6 +98,9 @@ type Node interface {
 	// RemoveChildren removes all children from this node.
 	RemoveChildren(self Node)
 
+	// SortChildren sorts childrens by comparator.
+	SortChildren(comparator func(n1, n2 Node) int)
+
 	// ReplaceChild replace a node v1 with a node insertee.
 	// If v1 is not children of this node, ReplaceChild append a insetee to the
 	// tail of the children.
@@ -243,6 +246,39 @@ func (n *BaseNode) RemoveChildren(self Node) {
 	n.childCount = 0
 }
 
+// SortChildren implements Node.SortChildren
+func (n *BaseNode) SortChildren(comparator func(n1, n2 Node) int) {
+	var sorted Node
+	current := n.firstChild
+	for current != nil {
+		next := current.NextSibling()
+		if sorted == nil || comparator(sorted, current) >= 0 {
+			current.SetNextSibling(sorted)
+			if sorted != nil {
+				sorted.SetPreviousSibling(current)
+			}
+			sorted = current
+			sorted.SetPreviousSibling(nil)
+		} else {
+			c := sorted
+			for c.NextSibling() != nil && comparator(c.NextSibling(), current) < 0 {
+				c = c.NextSibling()
+			}
+			current.SetNextSibling(c.NextSibling())
+			current.SetPreviousSibling(c)
+			if c.NextSibling() != nil {
+				c.NextSibling().SetPreviousSibling(current)
+			}
+			c.SetNextSibling(current)
+		}
+		current = next
+	}
+	n.firstChild = sorted
+	for c := n.firstChild; c != nil; c = c.NextSibling() {
+		n.lastChild = c
+	}
+}
+
 // FirstChild implements Node.FirstChild .
 func (n *BaseNode) FirstChild() Node {
 	return n.firstChild

extension/_test/footnote.txt

@@ -22,11 +22,28 @@ That's some text with a footnote.[^1]
 //- - - - - - - - -//
 [^000]:0	[^]:
 //- - - - - - - - -//
+//= = = = = = = = = = = = = = = = = = = = = = = =//
+
+4
+//- - - - - - - - -//
+This[^3] is[^1] text with footnotes[^2].
+
+[^1]: Footnote one
+[^2]: Footnote two
+[^3]: Footnote three
+//- - - - - - - - -//
+<p>This<sup id="fnref:1"><a href="#fn:1" class="footnote-ref" role="doc-noteref">1</a></sup> is<sup id="fnref:2"><a href="#fn:2" class="footnote-ref" role="doc-noteref">2</a></sup> text with footnotes<sup id="fnref:3"><a href="#fn:3" class="footnote-ref" role="doc-noteref">3</a></sup>.</p>
 <section class="footnotes" role="doc-endnotes">
 <hr>
 <ol>
 <li id="fn:1" role="doc-endnote">
-<p>0	[^]: <a href="#fnref:1" class="footnote-backref" role="doc-backlink">&#x21a9;&#xfe0e;</a></p>
+<p>Footnote three <a href="#fnref:1" class="footnote-backref" role="doc-backlink">&#x21a9;&#xfe0e;</a></p>
+</li>
+<li id="fn:2" role="doc-endnote">
+<p>Footnote one <a href="#fnref:2" class="footnote-backref" role="doc-backlink">&#x21a9;&#xfe0e;</a></p>
+</li>
+<li id="fn:3" role="doc-endnote">
+<p>Footnote two <a href="#fnref:3" class="footnote-backref" role="doc-backlink">&#x21a9;&#xfe0e;</a></p>
 </li>
 </ol>
 </section>

extension/ast/footnote.go

@@ -73,7 +73,10 @@ type Footnote struct {
 
 // Dump implements Node.Dump.
 func (n *Footnote) Dump(source []byte, level int) {
-	gast.DumpHelper(n, source, level, nil, nil)
+	m := map[string]string{}
+	m["Index"] = fmt.Sprintf("%v", n.Index)
+	m["Ref"] = fmt.Sprintf("%s", n.Ref)
+	gast.DumpHelper(n, source, level, m, nil)
 }
 
 // KindFootnote is a NodeKind of the Footnote node.
@@ -87,19 +90,23 @@ func (n *Footnote) Kind() gast.NodeKind {
 // NewFootnote returns a new Footnote node.
 func NewFootnote(ref []byte) *Footnote {
 	return &Footnote{
-		Ref: ref,
+		Ref:   ref,
+		Index: -1,
 	}
 }
 
 // A FootnoteList struct represents footnotes of Markdown
 // (PHP Markdown Extra) text.
 type FootnoteList struct {
 	gast.BaseBlock
+	Count int
 }
 
 // Dump implements Node.Dump.
 func (n *FootnoteList) Dump(source []byte, level int) {
-	gast.DumpHelper(n, source, level, nil, nil)
+	m := map[string]string{}
+	m["Count"] = fmt.Sprintf("%v", n.Count)
+	gast.DumpHelper(n, source, level, m, nil)
 }
 
 // KindFootnoteList is a NodeKind of the FootnoteList node.
@@ -112,5 +119,7 @@ func (n *FootnoteList) Kind() gast.NodeKind {
 
 // NewFootnoteList returns a new FootnoteList node.
 func NewFootnoteList() *FootnoteList {
-	return &FootnoteList{}
+	return &FootnoteList{
+		Count: 0,
+	}
 }

extension/footnote.go

@@ -91,9 +91,6 @@ func (b *footnoteBlockParser) Close(node gast.Node, reader text.Reader, pc parse
 		node.Parent().InsertBefore(node.Parent(), node, list)
 	}
 	node.Parent().RemoveChild(node.Parent(), node)
-	n := node.(*ast.Footnote)
-	index := list.ChildCount() + 1
-	n.Index = index
 	list.AppendChild(list, node)
 }
 
@@ -150,6 +147,10 @@ func (s *footnoteParser) Parse(parent gast.Node, block text.Reader, pc parser.Co
 	for def := list.FirstChild(); def != nil; def = def.NextSibling() {
 		d := def.(*ast.Footnote)
 		if bytes.Equal(d.Ref, value) {
+			if d.Index < 0 {
+				list.Count += 1
+				d.Index = list.Count
+			}
 			index = d.Index
 			break
 		}
@@ -180,14 +181,29 @@ func (a *footnoteASTTransformer) Transform(node *gast.Document, reader text.Read
 		return
 	}
 	pc.Set(footnoteListKey, nil)
-
-	for footnote := list.FirstChild(); footnote != nil; footnote = footnote.NextSibling() {
+	for footnote := list.FirstChild(); footnote != nil; {
 		var container gast.Node = footnote
+		next := footnote.NextSibling()
 		if fc := container.LastChild(); fc != nil && gast.IsParagraph(fc) {
 			container = fc
 		}
 		index := footnote.(*ast.Footnote).Index
-		container.AppendChild(container, ast.NewFootnoteBackLink(index))
+		if index < 0 {
+			list.RemoveChild(list, footnote)
+		} else {
+			container.AppendChild(container, ast.NewFootnoteBackLink(index))
+		}
+		footnote = next
+	}
+	list.SortChildren(func(n1, n2 gast.Node) int {
+		if n1.(*ast.Footnote).Index < n2.(*ast.Footnote).Index {
+			return -1
+		}
+		return 1
+	})
+	if list.Count <= 0 {
+		list.Parent().RemoveChild(list.Parent(), list)
+		return
 	}
 
 	node.AppendChild(node, list)

parser/attribute.go

@@ -99,6 +99,9 @@ func parseAttribute(reader text.Reader) (Attribute, bool) {
 		return Attribute{Name: name, Value: line[0:i]}, true
 	}
 	line, _ := reader.PeekLine()
+	if len(line) == 0 {
+		return Attribute{}, false
+	}
 	c = line[0]
 	if !((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') ||
 		c == '_' || c == ':') {