Enable full AST construction, use the new renderer

Connect the block and inline parsers. Most of the tests now pass, only a
couple fail, they need fixes in the test suite.

latex.go

@@ -359,3 +359,7 @@ func (r *Latex) DocumentHeader() {
 func (r *Latex) DocumentFooter() {
 	r.w.WriteString("\n\\end{document}\n")
 }
+
+func (r *Latex) Render(ast *Node) []byte {
+	return nil
+}

markdown.go

@@ -206,6 +206,8 @@ type Renderer interface {
 	CopyWrites(processor func()) []byte
 	Write(b []byte) (int, error)
 	GetResult() []byte
+
+	Render(ast *Node) []byte
 }
 
 // Callback functions for inline parsing. One such function is defined
@@ -437,8 +439,71 @@ func MarkdownOptions(input []byte, renderer Renderer, opts Options) []byte {
 	}
 
 	first := firstPass(p, input)
-	second := secondPass(p, first)
-	return second
+	secondPass(p, first)
+	// walk the tree and finish up some of unfinished blocks:
+	for p.tip != nil {
+		p.finalize(p.tip)
+	}
+	ForEachNode(p.doc, func(node *Node, entering bool) {
+		if node.Type == Paragraph || node.Type == Header || node.Type == TableCell {
+			p.currBlock = node
+			p.inline(node.content)
+			node.content = nil
+		}
+	})
+	p.parseRefsToAST()
+	return renderer.Render(p.doc)
+}
+
+func (p *parser) parseRefsToAST() {
+	if p.flags&Footnotes == 0 || len(p.notes) == 0 {
+		return
+	}
+	p.tip = p.doc
+	finalizeHtmlBlock(p.addBlock(HtmlBlock, []byte(`<div class="footnotes">`)))
+	p.addBlock(HorizontalRule, nil)
+	block := p.addBlock(List, nil)
+	block.ListData = &ListData{ // TODO: fill in the real ListData
+		Flags:      ListTypeOrdered,
+		Tight:      false,
+		BulletChar: '*',
+		Delimiter:  0,
+	}
+	flags := ListItemBeginningOfList
+	// Note: this loop is intentionally explicit, not range-form. This is
+	// because the body of the loop will append nested footnotes to p.notes and
+	// we need to process those late additions. Range form would only walk over
+	// the fixed initial set.
+	for i := 0; i < len(p.notes); i++ {
+		ref := p.notes[i]
+		block := p.addBlock(Item, nil)
+		block.ListData = &ListData{ // TODO: fill in the real ListData
+			Flags:      ListTypeOrdered,
+			Tight:      false,
+			BulletChar: '*',
+			Delimiter:  0,
+			RefLink:    ref.link,
+		}
+		if ref.hasBlock {
+			flags |= ListItemContainsBlock
+			p.block(ref.title)
+		} else {
+			p.currBlock = block
+			p.inline(ref.title)
+		}
+		flags &^= ListItemBeginningOfList | ListItemContainsBlock
+	}
+	above := block.Parent
+	finalizeList(block)
+	p.tip = above
+	finalizeHtmlBlock(p.addBlock(HtmlBlock, []byte("</div>")))
+	ForEachNode(block, func(node *Node, entering bool) {
+		if node.Type == Paragraph || node.Type == Header {
+			p.currBlock = node
+			p.inline(node.content)
+			node.content = nil
+		}
+	})
 }
 
 // first pass: