From 05645dd3c4666d1c9454cf5ff3e4270ab6325cc6 Mon Sep 17 00:00:00 2001
From: yuin <yuin@inforno.net>
Date: Thu, 30 May 2019 16:07:04 +0900
Subject: [PATCH] Add String node

---
 ast/inline.go                |  95 ++++++++++++++++++-
 extension/ast/typographer.go |  32 -------
 extension/typographer.go     |  62 ++++--------
 renderer/html/html.go        | 178 +++++++++++++++++++----------------
 4 files changed, 209 insertions(+), 158 deletions(-)
 delete mode 100644 extension/ast/typographer.go

diff --git a/ast/inline.go b/ast/inline.go
index 7404a3f..8c20402 100644
--- a/ast/inline.go
+++ b/ast/inline.go
@@ -56,8 +56,26 @@ const (
 	textSoftLineBreak = 1 << iota
 	textHardLineBreak
 	textRaw
+	textCode
 )
 
+func textFlagsString(flags uint8) string {
+	buf := []string{}
+	if flags&textSoftLineBreak != 0 {
+		buf = append(buf, "SoftLineBreak")
+	}
+	if flags&textHardLineBreak != 0 {
+		buf = append(buf, "HardLineBreak")
+	}
+	if flags&textRaw != 0 {
+		buf = append(buf, "Raw")
+	}
+	if flags&textCode != 0 {
+		buf = append(buf, "Code")
+	}
+	return strings.Join(buf, ", ")
+}
+
 // Inline implements Inline.Inline.
 func (n *Text) Inline() {
 }
@@ -130,7 +148,11 @@ func (n *Text) Text(source []byte) []byte {
 
 // Dump implements Node.Dump.
 func (n *Text) Dump(source []byte, level int) {
-	fmt.Printf("%sText: \"%s\"\n", strings.Repeat("    ", level), strings.TrimRight(string(n.Text(source)), "\n"))
+	fs := textFlagsString(n.flags)
+	if len(fs) != 0 {
+		fs = "(" + fs + ")"
+	}
+	fmt.Printf("%sText%s: \"%s\"\n", strings.Repeat("    ", level), fs, strings.TrimRight(string(n.Text(source)), "\n"))
 }
 
 // KindText is a NodeKind of the Text node.
@@ -192,6 +214,77 @@ func MergeOrReplaceTextSegment(parent Node, n Node, s textm.Segment) {
 	}
 }
 
+// A String struct is a textual content that has a concrete value
+type String struct {
+	BaseInline
+
+	Value []byte
+	flags uint8
+}
+
+// Inline implements Inline.Inline.
+func (n *String) Inline() {
+}
+
+// IsRaw returns true if this text should be rendered without unescaping
+// back slash escapes and resolving references.
+func (n *String) IsRaw() bool {
+	return n.flags&textRaw != 0
+}
+
+// SetRaw sets whether this text should be rendered as raw contents.
+func (n *String) SetRaw(v bool) {
+	if v {
+		n.flags |= textRaw
+	} else {
+		n.flags = n.flags &^ textRaw
+	}
+}
+
+// IsCode returns true if this text should be rendered without any
+// modifications.
+func (n *String) IsCode() bool {
+	return n.flags&textCode != 0
+}
+
+// SetCode sets whether this text should be rendered without any modifications.
+func (n *String) SetCode(v bool) {
+	if v {
+		n.flags |= textCode
+	} else {
+		n.flags = n.flags &^ textCode
+	}
+}
+
+// Text implements Node.Text.
+func (n *String) Text(source []byte) []byte {
+	return n.Value
+}
+
+// Dump implements Node.Dump.
+func (n *String) Dump(source []byte, level int) {
+	fs := textFlagsString(n.flags)
+	if len(fs) != 0 {
+		fs = "(" + fs + ")"
+	}
+	fmt.Printf("%sString%s: \"%s\"\n", strings.Repeat("    ", level), fs, strings.TrimRight(string(n.Value), "\n"))
+}
+
+// KindString is a NodeKind of the String node.
+var KindString = NewNodeKind("String")
+
+// Kind implements Node.Kind.
+func (n *String) Kind() NodeKind {
+	return KindString
+}
+
+// NewString returns a new String node.
+func NewString(v []byte) *String {
+	return &String{
+		Value: v,
+	}
+}
+
 // A CodeSpan struct represents a code span of Markdown text.
 type CodeSpan struct {
 	BaseInline
diff --git a/extension/ast/typographer.go b/extension/ast/typographer.go
deleted file mode 100644
index 4101b4d..0000000
--- a/extension/ast/typographer.go
+++ /dev/null
@@ -1,32 +0,0 @@
-package ast
-
-import (
-	gast "github.com/yuin/goldmark/ast"
-)
-
-// A TypographicText struct represents text that
-// typographic text replaces certain punctuations.
-type TypographicText struct {
-	gast.BaseInline
-	Value []byte
-}
-
-// Dump implements Node.Dump.
-func (n *TypographicText) Dump(source []byte, level int) {
-	gast.DumpHelper(n, source, level, nil, nil)
-}
-
-// KindTypographicText is a NodeKind of the TypographicText node.
-var KindTypographicText = gast.NewNodeKind("TypographicText")
-
-// Kind implements Node.Kind.
-func (n *TypographicText) Kind() gast.NodeKind {
-	return KindTypographicText
-}
-
-// NewTypographicText returns a new TypographicText node.
-func NewTypographicText(value []byte) *TypographicText {
-	return &TypographicText{
-		Value: value,
-	}
-}
diff --git a/extension/typographer.go b/extension/typographer.go
index 490fb5a..a267980 100644
--- a/extension/typographer.go
+++ b/extension/typographer.go
@@ -3,10 +3,7 @@ package extension
 import (
 	"github.com/yuin/goldmark"
 	gast "github.com/yuin/goldmark/ast"
-	"github.com/yuin/goldmark/extension/ast"
 	"github.com/yuin/goldmark/parser"
-	"github.com/yuin/goldmark/renderer"
-	"github.com/yuin/goldmark/renderer/html"
 	"github.com/yuin/goldmark/text"
 	"github.com/yuin/goldmark/util"
 )
@@ -147,13 +144,15 @@ func (s *typographerParser) Parse(parent gast.Node, block text.Reader, pc parser
 	if len(line) > 2 {
 		if c == '-' {
 			if s.Substitutions[EmDash] != nil && line[1] == '-' && line[2] == '-' { // ---
-				node := ast.NewTypographicText(s.Substitutions[EmDash])
+				node := gast.NewString(s.Substitutions[EmDash])
+				node.SetCode(true)
 				block.Advance(3)
 				return node
 			}
 		} else if c == '.' {
 			if s.Substitutions[Ellipsis] != nil && line[1] == '.' && line[2] == '.' { // ...
-				node := ast.NewTypographicText(s.Substitutions[Ellipsis])
+				node := gast.NewString(s.Substitutions[Ellipsis])
+				node.SetCode(true)
 				block.Advance(3)
 				return node
 			}
@@ -163,20 +162,23 @@ func (s *typographerParser) Parse(parent gast.Node, block text.Reader, pc parser
 	if len(line) > 1 {
 		if c == '<' {
 			if s.Substitutions[LeftAngleQuote] != nil && line[1] == '<' { // <<
-				node := ast.NewTypographicText(s.Substitutions[LeftAngleQuote])
+				node := gast.NewString(s.Substitutions[LeftAngleQuote])
+				node.SetCode(true)
 				block.Advance(2)
 				return node
 			}
 			return nil
 		} else if c == '>' {
 			if s.Substitutions[RightAngleQuote] != nil && line[1] == '>' { // >>
-				node := ast.NewTypographicText(s.Substitutions[RightAngleQuote])
+				node := gast.NewString(s.Substitutions[RightAngleQuote])
+				node.SetCode(true)
 				block.Advance(2)
 				return node
 			}
 			return nil
 		} else if s.Substitutions[EnDash] != nil && c == '-' && line[1] == '-' { // --
-			node := ast.NewTypographicText(s.Substitutions[EnDash])
+			node := gast.NewString(s.Substitutions[EnDash])
+			node.SetCode(true)
 			block.Advance(2)
 			return node
 		}
@@ -188,24 +190,28 @@ func (s *typographerParser) Parse(parent gast.Node, block text.Reader, pc parser
 		}
 		if c == '\'' {
 			if s.Substitutions[LeftSingleQuote] != nil && d.CanOpen && !d.CanClose {
-				node := ast.NewTypographicText(s.Substitutions[LeftSingleQuote])
+				node := gast.NewString(s.Substitutions[LeftSingleQuote])
+				node.SetCode(true)
 				block.Advance(1)
 				return node
 			}
 			if s.Substitutions[RightSingleQuote] != nil && d.CanClose && !d.CanOpen {
-				node := ast.NewTypographicText(s.Substitutions[RightSingleQuote])
+				node := gast.NewString(s.Substitutions[RightSingleQuote])
+				node.SetCode(true)
 				block.Advance(1)
 				return node
 			}
 		}
 		if c == '"' {
 			if s.Substitutions[LeftDoubleQuote] != nil && d.CanOpen && !d.CanClose {
-				node := ast.NewTypographicText(s.Substitutions[LeftDoubleQuote])
+				node := gast.NewString(s.Substitutions[LeftDoubleQuote])
+				node.SetCode(true)
 				block.Advance(1)
 				return node
 			}
 			if s.Substitutions[RightDoubleQuote] != nil && d.CanClose && !d.CanOpen {
-				node := ast.NewTypographicText(s.Substitutions[RightDoubleQuote])
+				node := gast.NewString(s.Substitutions[RightDoubleQuote])
+				node.SetCode(true)
 				block.Advance(1)
 				return node
 			}
@@ -218,35 +224,6 @@ func (s *typographerParser) CloseBlock(parent gast.Node, pc parser.Context) {
 	// nothing to do
 }
 
-// TypographerHTMLRenderer is a renderer.NodeRenderer implementation that
-// renders Typographer nodes.
-type TypographerHTMLRenderer struct {
-	html.Config
-}
-
-// NewTypographerHTMLRenderer returns a new TypographerHTMLRenderer.
-func NewTypographerHTMLRenderer(opts ...html.Option) renderer.NodeRenderer {
-	r := &TypographerHTMLRenderer{
-		Config: html.NewConfig(),
-	}
-	for _, opt := range opts {
-		opt.SetHTMLOption(&r.Config)
-	}
-	return r
-}
-
-// RegisterFuncs implements renderer.NodeRenderer.RegisterFuncs.
-func (r *TypographerHTMLRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
-	reg.Register(ast.KindTypographicText, r.renderTypographicText)
-}
-
-func (r *TypographerHTMLRenderer) renderTypographicText(w util.BufWriter, source []byte, n gast.Node, entering bool) (gast.WalkStatus, error) {
-	if entering {
-		w.Write(n.(*ast.TypographicText).Value)
-	}
-	return gast.WalkContinue, nil
-}
-
 type typographer struct {
 	options []TypographerOption
 }
@@ -265,7 +242,4 @@ func (e *typographer) Extend(m goldmark.Markdown) {
 	m.Parser().AddOptions(parser.WithInlineParsers(
 		util.Prioritized(NewTypographerParser(e.options...), 9999),
 	))
-	m.Renderer().AddOptions(renderer.WithNodeRenderers(
-		util.Prioritized(NewTypographerHTMLRenderer(), 500),
-	))
 }
diff --git a/renderer/html/html.go b/renderer/html/html.go
index 8551b78..bfd9761 100644
--- a/renderer/html/html.go
+++ b/renderer/html/html.go
@@ -183,6 +183,7 @@ func (r *Renderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
 	reg.Register(ast.KindLink, r.renderLink)
 	reg.Register(ast.KindRawHTML, r.renderRawHTML)
 	reg.Register(ast.KindText, r.renderText)
+	reg.Register(ast.KindString, r.renderString)
 }
 
 func (r *Renderer) writeLines(w util.BufWriter, source []byte, n ast.Node) {
@@ -198,40 +199,38 @@ func (r *Renderer) renderDocument(w util.BufWriter, source []byte, node ast.Node
 	return ast.WalkContinue, nil
 }
 
-var attrNameID = []byte("id")
-
 func (r *Renderer) renderHeading(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
 	n := node.(*ast.Heading)
 	if entering {
-		w.WriteString("<h")
-		w.WriteByte("0123456"[n.Level])
+		_, _ = w.WriteString("<h")
+		_ = w.WriteByte("0123456"[n.Level])
 		if n.Attributes() != nil {
 			r.RenderAttributes(w, node)
 		}
-		w.WriteByte('>')
+		_ = w.WriteByte('>')
 	} else {
-		w.WriteString("</h")
-		w.WriteByte("0123456"[n.Level])
-		w.WriteString(">\n")
+		_, _ = w.WriteString("</h")
+		_ = w.WriteByte("0123456"[n.Level])
+		_, _ = w.WriteString(">\n")
 	}
 	return ast.WalkContinue, nil
 }
 
 func (r *Renderer) renderBlockquote(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
 	if entering {
-		w.WriteString("<blockquote>\n")
+		_, _ = w.WriteString("<blockquote>\n")
 	} else {
-		w.WriteString("</blockquote>\n")
+		_, _ = w.WriteString("</blockquote>\n")
 	}
 	return ast.WalkContinue, nil
 }
 
 func (r *Renderer) renderCodeBlock(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
 	if entering {
-		w.WriteString("<pre><code>")
+		_, _ = w.WriteString("<pre><code>")
 		r.writeLines(w, source, n)
 	} else {
-		w.WriteString("</code></pre>\n")
+		_, _ = w.WriteString("</code></pre>\n")
 	}
 	return ast.WalkContinue, nil
 }
@@ -239,17 +238,17 @@ func (r *Renderer) renderCodeBlock(w util.BufWriter, source []byte, n ast.Node,
 func (r *Renderer) renderFencedCodeBlock(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
 	n := node.(*ast.FencedCodeBlock)
 	if entering {
-		w.WriteString("<pre><code")
+		_, _ = w.WriteString("<pre><code")
 		language := n.Language(source)
 		if language != nil {
-			w.WriteString(" class=\"language-")
+			_, _ = w.WriteString(" class=\"language-")
 			r.Writer.Write(w, language)
-			w.WriteString("\"")
+			_, _ = w.WriteString("\"")
 		}
-		w.WriteByte('>')
+		_ = w.WriteByte('>')
 		r.writeLines(w, source, n)
 	} else {
-		w.WriteString("</code></pre>\n")
+		_, _ = w.WriteString("</code></pre>\n")
 	}
 	return ast.WalkContinue, nil
 }
@@ -261,18 +260,18 @@ func (r *Renderer) renderHTMLBlock(w util.BufWriter, source []byte, node ast.Nod
 			l := n.Lines().Len()
 			for i := 0; i < l; i++ {
 				line := n.Lines().At(i)
-				w.Write(line.Value(source))
+				_, _ = w.Write(line.Value(source))
 			}
 		} else {
-			w.WriteString("<!-- raw HTML omitted -->\n")
+			_, _ = w.WriteString("<!-- raw HTML omitted -->\n")
 		}
 	} else {
 		if n.HasClosure() {
 			if r.Unsafe {
 				closure := n.ClosureLine
-				w.Write(closure.Value(source))
+				_, _ = w.Write(closure.Value(source))
 			} else {
-				w.WriteString("<!-- raw HTML omitted -->\n")
+				_, _ = w.WriteString("<!-- raw HTML omitted -->\n")
 			}
 		}
 	}
@@ -286,41 +285,41 @@ func (r *Renderer) renderList(w util.BufWriter, source []byte, node ast.Node, en
 		tag = "ol"
 	}
 	if entering {
-		w.WriteByte('<')
-		w.WriteString(tag)
+		_ = w.WriteByte('<')
+		_, _ = w.WriteString(tag)
 		if n.IsOrdered() && n.Start != 1 {
 			fmt.Fprintf(w, " start=\"%d\">\n", n.Start)
 		} else {
-			w.WriteString(">\n")
+			_, _ = w.WriteString(">\n")
 		}
 	} else {
-		w.WriteString("</")
-		w.WriteString(tag)
-		w.WriteString(">\n")
+		_, _ = w.WriteString("</")
+		_, _ = w.WriteString(tag)
+		_, _ = w.WriteString(">\n")
 	}
 	return ast.WalkContinue, nil
 }
 
 func (r *Renderer) renderListItem(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
 	if entering {
-		w.WriteString("<li>")
+		_, _ = w.WriteString("<li>")
 		fc := n.FirstChild()
 		if fc != nil {
 			if _, ok := fc.(*ast.TextBlock); !ok {
-				w.WriteByte('\n')
+				_ = w.WriteByte('\n')
 			}
 		}
 	} else {
-		w.WriteString("</li>\n")
+		_, _ = w.WriteString("</li>\n")
 	}
 	return ast.WalkContinue, nil
 }
 
 func (r *Renderer) renderParagraph(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
 	if entering {
-		w.WriteString("<p>")
+		_, _ = w.WriteString("<p>")
 	} else {
-		w.WriteString("</p>\n")
+		_, _ = w.WriteString("</p>\n")
 	}
 	return ast.WalkContinue, nil
 }
@@ -328,7 +327,7 @@ func (r *Renderer) renderParagraph(w util.BufWriter, source []byte, n ast.Node,
 func (r *Renderer) renderTextBlock(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
 	if !entering {
 		if _, ok := n.NextSibling().(ast.Node); ok && n.FirstChild() != nil {
-			w.WriteByte('\n')
+			_ = w.WriteByte('\n')
 		}
 	}
 	return ast.WalkContinue, nil
@@ -339,9 +338,9 @@ func (r *Renderer) renderThemanticBreak(w util.BufWriter, source []byte, n ast.N
 		return ast.WalkContinue, nil
 	}
 	if r.XHTML {
-		w.WriteString("<hr />\n")
+		_, _ = w.WriteString("<hr />\n")
 	} else {
-		w.WriteString("<hr>\n")
+		_, _ = w.WriteString("<hr>\n")
 	}
 	return ast.WalkContinue, nil
 }
@@ -351,22 +350,22 @@ func (r *Renderer) renderAutoLink(w util.BufWriter, source []byte, node ast.Node
 	if !entering {
 		return ast.WalkContinue, nil
 	}
-	w.WriteString(`<a href="`)
+	_, _ = w.WriteString(`<a href="`)
 	url := n.URL(source)
 	label := n.Label(source)
 	if n.AutoLinkType == ast.AutoLinkEmail && !bytes.HasPrefix(bytes.ToLower(url), []byte("mailto:")) {
-		w.WriteString("mailto:")
+		_, _ = w.WriteString("mailto:")
 	}
-	w.Write(util.EscapeHTML(util.URLEscape(url, false)))
-	w.WriteString(`">`)
-	w.Write(util.EscapeHTML(label))
-	w.WriteString(`</a>`)
+	_, _ = w.Write(util.EscapeHTML(util.URLEscape(url, false)))
+	_, _ = w.WriteString(`">`)
+	_, _ = w.Write(util.EscapeHTML(label))
+	_, _ = w.WriteString(`</a>`)
 	return ast.WalkContinue, nil
 }
 
 func (r *Renderer) renderCodeSpan(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
 	if entering {
-		w.WriteString("<code>")
+		_, _ = w.WriteString("<code>")
 		for c := n.FirstChild(); c != nil; c = c.NextSibling() {
 			segment := c.(*ast.Text).Segment
 			value := segment.Value(source)
@@ -381,7 +380,7 @@ func (r *Renderer) renderCodeSpan(w util.BufWriter, source []byte, n ast.Node, e
 		}
 		return ast.WalkSkipChildren, nil
 	}
-	w.WriteString("</code>")
+	_, _ = w.WriteString("</code>")
 	return ast.WalkContinue, nil
 }
 
@@ -392,13 +391,13 @@ func (r *Renderer) renderEmphasis(w util.BufWriter, source []byte, node ast.Node
 		tag = "strong"
 	}
 	if entering {
-		w.WriteByte('<')
-		w.WriteString(tag)
-		w.WriteByte('>')
+		_ = w.WriteByte('<')
+		_, _ = w.WriteString(tag)
+		_ = w.WriteByte('>')
 	} else {
-		w.WriteString("</")
-		w.WriteString(tag)
-		w.WriteByte('>')
+		_, _ = w.WriteString("</")
+		_, _ = w.WriteString(tag)
+		_ = w.WriteByte('>')
 	}
 	return ast.WalkContinue, nil
 }
@@ -406,19 +405,19 @@ func (r *Renderer) renderEmphasis(w util.BufWriter, source []byte, node ast.Node
 func (r *Renderer) renderLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
 	n := node.(*ast.Link)
 	if entering {
-		w.WriteString("<a href=\"")
+		_, _ = w.WriteString("<a href=\"")
 		if r.Unsafe || !IsDangerousURL(n.Destination) {
-			w.Write(util.EscapeHTML(util.URLEscape(n.Destination, true)))
+			_, _ = w.Write(util.EscapeHTML(util.URLEscape(n.Destination, true)))
 		}
-		w.WriteByte('"')
+		_ = w.WriteByte('"')
 		if n.Title != nil {
-			w.WriteString(` title="`)
+			_, _ = w.WriteString(` title="`)
 			r.Writer.Write(w, n.Title)
-			w.WriteByte('"')
+			_ = w.WriteByte('"')
 		}
-		w.WriteByte('>')
+		_ = w.WriteByte('>')
 	} else {
-		w.WriteString("</a>")
+		_, _ = w.WriteString("</a>")
 	}
 	return ast.WalkContinue, nil
 }
@@ -427,22 +426,22 @@ func (r *Renderer) renderImage(w util.BufWriter, source []byte, node ast.Node, e
 		return ast.WalkContinue, nil
 	}
 	n := node.(*ast.Image)
-	w.WriteString("<img src=\"")
+	_, _ = w.WriteString("<img src=\"")
 	if r.Unsafe || !IsDangerousURL(n.Destination) {
-		w.Write(util.EscapeHTML(util.URLEscape(n.Destination, true)))
+		_, _ = w.Write(util.EscapeHTML(util.URLEscape(n.Destination, true)))
 	}
-	w.WriteString(`" alt="`)
-	w.Write(n.Text(source))
-	w.WriteByte('"')
+	_, _ = w.WriteString(`" alt="`)
+	_, _ = w.Write(n.Text(source))
+	_ = w.WriteByte('"')
 	if n.Title != nil {
-		w.WriteString(` title="`)
+		_, _ = w.WriteString(` title="`)
 		r.Writer.Write(w, n.Title)
-		w.WriteByte('"')
+		_ = w.WriteByte('"')
 	}
 	if r.XHTML {
-		w.WriteString(" />")
+		_, _ = w.WriteString(" />")
 	} else {
-		w.WriteString(">")
+		_, _ = w.WriteString(">")
 	}
 	return ast.WalkSkipChildren, nil
 }
@@ -456,11 +455,11 @@ func (r *Renderer) renderRawHTML(w util.BufWriter, source []byte, node ast.Node,
 		l := n.Segments.Len()
 		for i := 0; i < l; i++ {
 			segment := n.Segments.At(i)
-			w.Write(segment.Value(source))
+			_, _ = w.Write(segment.Value(source))
 		}
 		return ast.WalkSkipChildren, nil
 	}
-	w.WriteString("<!-- raw HTML omitted -->")
+	_, _ = w.WriteString("<!-- raw HTML omitted -->")
 	return ast.WalkSkipChildren, nil
 }
 
@@ -476,12 +475,29 @@ func (r *Renderer) renderText(w util.BufWriter, source []byte, node ast.Node, en
 		r.Writer.Write(w, segment.Value(source))
 		if n.HardLineBreak() || (n.SoftLineBreak() && r.HardWraps) {
 			if r.XHTML {
-				w.WriteString("<br />\n")
+				_, _ = w.WriteString("<br />\n")
 			} else {
-				w.WriteString("<br>\n")
+				_, _ = w.WriteString("<br>\n")
 			}
 		} else if n.SoftLineBreak() {
-			w.WriteByte('\n')
+			_ = w.WriteByte('\n')
+		}
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderString(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+	n := node.(*ast.String)
+	if n.IsCode() {
+		_, _ = w.Write(n.Value)
+	} else {
+		if n.IsRaw() {
+			r.Writer.RawWrite(w, n.Value)
+		} else {
+			r.Writer.Write(w, n.Value)
 		}
 	}
 	return ast.WalkContinue, nil
@@ -490,11 +506,11 @@ func (r *Renderer) renderText(w util.BufWriter, source []byte, node ast.Node, en
 // RenderAttributes renders given node's attributes.
 func (r *Renderer) RenderAttributes(w util.BufWriter, node ast.Node) {
 	for _, attr := range node.Attributes() {
-		w.WriteString(" ")
-		w.Write(attr.Name)
-		w.WriteString(`="`)
-		w.Write(util.EscapeHTML(attr.Value))
-		w.WriteByte('"')
+		_, _ = w.WriteString(" ")
+		_, _ = w.Write(attr.Name)
+		_, _ = w.WriteString(`="`)
+		_, _ = w.Write(util.EscapeHTML(attr.Value))
+		_ = w.WriteByte('"')
 	}
 }
 
@@ -516,11 +532,11 @@ func escapeRune(writer util.BufWriter, r rune) {
 	if r < 256 {
 		v := util.EscapeHTMLByte(byte(r))
 		if v != nil {
-			writer.Write(v)
+			_, _ = writer.Write(v)
 			return
 		}
 	}
-	writer.WriteRune(util.ToValidRune(r))
+	_, _ = writer.WriteRune(util.ToValidRune(r))
 }
 
 func (d *defaultWriter) RawWrite(writer util.BufWriter, source []byte) {
@@ -529,21 +545,21 @@ func (d *defaultWriter) RawWrite(writer util.BufWriter, source []byte) {
 	for i := 0; i < l; i++ {
 		v := util.EscapeHTMLByte(source[i])
 		if v != nil {
-			writer.Write(source[i-n : i])
+			_, _ = writer.Write(source[i-n : i])
 			n = 0
-			writer.Write(v)
+			_, _ = writer.Write(v)
 			continue
 		}
 		n++
 	}
 	if n != 0 {
-		writer.Write(source[l-n:])
+		_, _ = writer.Write(source[l-n:])
 	}
 }
 
 func (d *defaultWriter) Write(writer util.BufWriter, source []byte) {
 	escaped := false
-	ok := false
+	var ok bool
 	limit := len(source)
 	n := 0
 	for i := 0; i < limit; i++ {