all: cleaning up codes

Use raw string literal whenever possible.

28 files changed, 623 insertions, 623 deletions

diff --git a/asciidoctor.go b/asciidoctor.go
index 6e68f84..6849811 100644
--- a/asciidoctor.go
+++ b/asciidoctor.go
@@ -6,7 +6,7 @@ package asciidoctor
 import "github.com/shuLhan/share/lib/math/big"
 
 const (
-	Version = "0.3.0"
+	Version = `0.3.0`
 )
 
 func init() {
diff --git a/asciidoctor_test.go b/asciidoctor_test.go
index 168607b..387c5ed 100644
--- a/asciidoctor_test.go
+++ b/asciidoctor_test.go
@@ -11,9 +11,9 @@ import (
 )
 
 const (
-	outputCallHtmlWriteHeader = "htmlWriteHeader"
-	outputCallToHTML          = "ToHTML"
-	outputCallToHTMLBody      = "ToHTMLBody"
+	outputCallHtmlWriteHeader = `htmlWriteHeader`
+	outputCallToHTML          = `ToHTML`
+	outputCallToHTMLBody      = `ToHTMLBody`
 )
 
 func TestData(t *testing.T) {
@@ -28,17 +28,17 @@ func TestData(t *testing.T) {
 		err          error
 	)
 
-	listTData, err = test.LoadDataDir("testdata")
+	listTData, err = test.LoadDataDir(`testdata`)
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	for _, tdata = range listTData {
-		inputCall = tdata.Flag["input_call"]
-		outputCall = tdata.Flag["output_call"]
+		inputCall = tdata.Flag[`input_call`]
+		outputCall = tdata.Flag[`output_call`]
 
 		for inputName, inputContent = range tdata.Input {
-			subtestName = tdata.Name + "/" + inputName
+			subtestName = tdata.Name + `/` + inputName
 
 			t.Run(subtestName, func(t *testing.T) {
 				var (
diff --git a/attribute_class.go b/attribute_class.go
index d3e1a57..6e694a4 100644
--- a/attribute_class.go
+++ b/attribute_class.go
@@ -34,5 +34,5 @@ func (aclass *attributeClass) replace(old, new string) {
 // String concat all the attribute class into string separated by single
 // space.
 func (aclass attributeClass) String() string {
-	return strings.Join(aclass, " ")
+	return strings.Join(aclass, ` `)
 }
diff --git a/attribute_entry.go b/attribute_entry.go
index 7d5d794..a4dd722 100644
--- a/attribute_entry.go
+++ b/attribute_entry.go
@@ -11,11 +11,11 @@ type AttributeEntry map[string]string
 
 func newAttributeEntry() AttributeEntry {
 	return AttributeEntry{
-		MetaNameGenerator:    "asciidoctor-go " + Version,
-		metaNameSectIDs:      "",
-		metaNameShowTitle:    "",
-		metaNameTableCaption: "",
-		metaNameVersionLabel: "",
+		MetaNameGenerator:    `asciidoctor-go ` + Version,
+		metaNameSectIDs:      ``,
+		metaNameShowTitle:    ``,
+		metaNameTableCaption: ``,
+		metaNameVersionLabel: ``,
 	}
 }
 
diff --git a/author.go b/author.go
index 20ce292..57ccad8 100644
--- a/author.go
+++ b/author.go
@@ -36,21 +36,21 @@ func parseAuthor(raw string) (author *Author) {
 		}
 	}
 
-	names = strings.Split(raw, " ")
+	names = strings.Split(raw, ` `)
 	if len(names) == 0 {
 		return
 	}
 
 	var initials bytes.Buffer
-	author.FirstName = strings.ReplaceAll(names[0], "_", " ")
+	author.FirstName = strings.ReplaceAll(names[0], `_`, ` `)
 	initials.WriteByte(author.FirstName[0])
 
 	if len(names) >= 2 {
 		lastIdx = len(names) - 1
-		author.LastName = strings.ReplaceAll(names[lastIdx], "_", " ")
+		author.LastName = strings.ReplaceAll(names[lastIdx], `_`, ` `)
 
 		author.MiddleName = strings.ReplaceAll(
-			strings.Join(names[1:lastIdx], " "), "_", " ",
+			strings.Join(names[1:lastIdx], ` `), `_`, ` `,
 		)
 
 		if len(author.MiddleName) > 0 {
@@ -70,10 +70,10 @@ func (author *Author) FullName() string {
 
 	sb.WriteString(author.FirstName)
 	if len(author.MiddleName) > 0 {
-		sb.WriteString(" " + author.MiddleName)
+		sb.WriteString(` ` + author.MiddleName)
 	}
 	if len(author.LastName) > 0 {
-		sb.WriteString(" " + author.LastName)
+		sb.WriteString(` ` + author.LastName)
 	}
 	return sb.String()
 }
diff --git a/cell_format_test.go b/cell_format_test.go
index 117292a..3c33cd6 100644
--- a/cell_format_test.go
+++ b/cell_format_test.go
@@ -16,52 +16,52 @@ func TestParseCellFormat(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		raw: "3*",
+		raw: `3*`,
 		exp: &cellFormat{
 			ndupCol: 3,
 		},
 	}, {
-		raw: "3+",
+		raw: `3+`,
 		exp: &cellFormat{
 			nspanCol: 3,
 		},
 	}, {
-		raw: ".2+",
+		raw: `.2+`,
 		exp: &cellFormat{
 			nspanRow: 2,
 		},
 	}, {
-		raw: "2.3+",
+		raw: `2.3+`,
 		exp: &cellFormat{
 			nspanCol: 2,
 			nspanRow: 3,
 		},
 	}, {
-		raw: "^",
+		raw: `^`,
 		exp: &cellFormat{
 			alignHor: colAlignMiddle,
 		},
 	}, {
-		raw: ".<",
+		raw: `.<`,
 		exp: &cellFormat{
 			alignVer: colAlignTop,
 		},
 	}, {
-		raw: "3+^.^",
+		raw: `3+^.^`,
 		exp: &cellFormat{
 			nspanCol: 3,
 			alignHor: colAlignMiddle,
 			alignVer: colAlignMiddle,
 		},
 	}, {
-		raw: "2*>m",
+		raw: `2*>m`,
 		exp: &cellFormat{
 			ndupCol:  2,
 			alignHor: colAlignBottom,
 			style:    colStyleMonospaced,
 		},
 	}, {
-		raw: ".3+^.>s",
+		raw: `.3+^.>s`,
 		exp: &cellFormat{
 			nspanRow: 3,
 			alignHor: colAlignMiddle,
@@ -69,13 +69,13 @@ func TestParseCellFormat(t *testing.T) {
 			style:    colStyleStrong,
 		},
 	}, {
-		raw: ".^l",
+		raw: `.^l`,
 		exp: &cellFormat{
 			alignVer: colAlignMiddle,
 			style:    colStyleLiteral,
 		},
 	}, {
-		raw: "v",
+		raw: `v`,
 		exp: &cellFormat{
 			style: colStyleVerse,
 		},
diff --git a/column_format.go b/column_format.go
index b6ac9f4..52ac250 100644
--- a/column_format.go
+++ b/column_format.go
@@ -60,7 +60,7 @@ func newColumnFormat() *columnFormat {
 }
 
 func (f *columnFormat) htmlClasses() string {
-	return strings.Join(f.classes, " ")
+	return strings.Join(f.classes, ` `)
 }
 
 func (f *columnFormat) merge(other *columnFormat) {
diff --git a/column_format_test.go b/column_format_test.go
index b9f1111..ebb1277 100644
--- a/column_format_test.go
+++ b/column_format_test.go
@@ -18,14 +18,14 @@ func TestParseColumnFormat(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		s:        "3*",
+		s:        `3*`,
 		expNCols: 3,
 		expFormat: &columnFormat{
 			isDefault: true,
 			width:     big.NewRat(1),
 		},
 	}, {
-		s:        "3*^",
+		s:        `3*^`,
 		expNCols: 3,
 		expFormat: &columnFormat{
 			alignHor:  colAlignMiddle,
@@ -33,7 +33,7 @@ func TestParseColumnFormat(t *testing.T) {
 			width:     big.NewRat(1),
 		},
 	}, {
-		s:        "3*.^",
+		s:        `3*.^`,
 		expNCols: 3,
 		expFormat: &columnFormat{
 			alignVer:  colAlignMiddle,
@@ -50,7 +50,7 @@ func TestParseColumnFormat(t *testing.T) {
 
 	for _, c = range cases {
 		gotNCols, gotFormat = parseColumnFormat(c.s)
-		test.Assert(t, c.s+" ncols", c.expNCols, gotNCols)
+		test.Assert(t, c.s+` ncols`, c.expNCols, gotNCols)
 		test.Assert(t, c.s, c.expFormat, gotFormat)
 	}
 }
diff --git a/document.go b/document.go
index 2fae03d..8b9d42e 100644
--- a/document.go
+++ b/document.go
@@ -17,9 +17,9 @@ import (
 const (
 	defSectnumlevels  = 3
 	defTOCLevel       = 2
-	defTOCTitle       = "Table of Contents"
+	defTOCTitle       = `Table of Contents`
 	defTitleSeparator = ':'
-	defVersionPrefix  = "version "
+	defVersionPrefix  = `version `
 )
 
 // Document represent content of asciidoc that has been parsed.
@@ -114,18 +114,18 @@ func Open(file string) (doc *Document, err error) {
 
 	raw, err = os.ReadFile(file)
 	if err != nil {
-		return nil, fmt.Errorf("Open %s: %w", file, err)
+		return nil, fmt.Errorf(`Open %s: %w`, file, err)
 	}
 
 	wd, err = os.Getwd()
 	if err != nil {
-		return nil, fmt.Errorf("Open %s: %w", file, err)
+		return nil, fmt.Errorf(`Open %s: %w`, file, err)
 	}
 
 	doc = newDocument()
 	doc.fpath = filepath.Join(wd, file)
 	doc.file = file
-	doc.LastUpdated = fi.ModTime().Round(time.Second).Format("2006-01-02 15:04:05 Z0700")
+	doc.LastUpdated = fi.ModTime().Round(time.Second).Format(`2006-01-02 15:04:05 Z0700`)
 
 	parse(doc, raw)
 
@@ -304,7 +304,7 @@ func (doc *Document) registerAnchor(id, label string) string {
 	for ok {
 		// The ID is duplicate
 		got.counter++
-		id = fmt.Sprintf("%s_%d", id, got.counter)
+		id = fmt.Sprintf(`%s_%d`, id, got.counter)
 		got, ok = doc.anchors[id]
 	}
 	doc.anchors[id] = &anchor{
@@ -359,9 +359,9 @@ func (doc *Document) unpackRawAuthor() {
 		}
 		v = doc.Attributes[metaNameEmail]
 		if len(v) > 0 {
-			sb.WriteString(" <")
+			sb.WriteString(` <`)
 			sb.WriteString(v)
-			sb.WriteString(">")
+			sb.WriteString(`>`)
 		}
 		v = sb.String()
 		if len(v) == 0 {
@@ -371,7 +371,7 @@ func (doc *Document) unpackRawAuthor() {
 	}
 
 	var (
-		rawAuthors    []string = strings.Split(doc.rawAuthors, ";")
+		rawAuthors    []string = strings.Split(doc.rawAuthors, `;`)
 		authorKey              = MetaNameAuthor
 		emailKey               = metaNameEmail
 		initialsKey            = metaNameAuthorInitials
@@ -395,7 +395,7 @@ func (doc *Document) unpackRawAuthor() {
 		doc.Authors = append(doc.Authors, author)
 
 		if len(doc.Authors) >= 2 {
-			sb.WriteString(", ")
+			sb.WriteString(`, `)
 		}
 		sb.WriteString(author.FullName())
 
@@ -408,15 +408,15 @@ func (doc *Document) unpackRawAuthor() {
 			doc.Attributes[lastNameKey] = author.LastName
 
 			// No continue, the first author have two keys, one is
-			// "author" and another is "author_1".
+			// `author` and another is `author_1`.
 		}
 
-		authorKey = fmt.Sprintf("%s_%d", MetaNameAuthor, x+1)
-		emailKey = fmt.Sprintf("%s_%d", metaNameEmail, x+1)
-		initialsKey = fmt.Sprintf("%s_%d", metaNameAuthorInitials, x+1)
-		firstNameKey = fmt.Sprintf("%s_%d", metaNameFirstName, x+1)
-		middleNameKey = fmt.Sprintf("%s_%d", metaNameMiddleName, x+1)
-		lastNameKey = fmt.Sprintf("%s_%d", metaNameLastName, x+1)
+		authorKey = fmt.Sprintf(`%s_%d`, MetaNameAuthor, x+1)
+		emailKey = fmt.Sprintf(`%s_%d`, metaNameEmail, x+1)
+		initialsKey = fmt.Sprintf(`%s_%d`, metaNameAuthorInitials, x+1)
+		firstNameKey = fmt.Sprintf(`%s_%d`, metaNameFirstName, x+1)
+		middleNameKey = fmt.Sprintf(`%s_%d`, metaNameMiddleName, x+1)
+		lastNameKey = fmt.Sprintf(`%s_%d`, metaNameLastName, x+1)
 
 		doc.Attributes[authorKey] = author.FullName()
 		doc.Attributes[emailKey] = author.Email
@@ -482,7 +482,7 @@ func (doc *Document) unpackRawTitle() {
 }
 
 // unpackTitleSeparator set the Title separator using the first character in
-// meta attribute "title-separator" value.
+// meta attribute `title-separator` value.
 func (doc *Document) unpackTitleSeparator() {
 	var (
 		v  string
diff --git a/document_parser.go b/document_parser.go
index 608b95c..2227ed2 100644
--- a/document_parser.go
+++ b/document_parser.go
@@ -581,11 +581,11 @@ func (docp *documentParser) parseHeader() {
 		if len(line) == 0 {
 			return
 		}
-		if bytes.HasPrefix(line, []byte("////")) {
+		if bytes.HasPrefix(line, []byte(`////`)) {
 			docp.parseIgnoreCommentBlock()
 			continue
 		}
-		if bytes.HasPrefix(line, []byte("//")) {
+		if bytes.HasPrefix(line, []byte(`//`)) {
 			continue
 		}
 		if line[0] == ':' {
@@ -629,13 +629,13 @@ func (docp *documentParser) parseIgnoreCommentBlock() {
 		if !ok {
 			return
 		}
-		if bytes.HasPrefix(line, []byte("////")) {
+		if bytes.HasPrefix(line, []byte(`////`)) {
 			return
 		}
 	}
 }
 
-// parseListBlock parse block after list continuation "+" until we found
+// parseListBlock parse block after list continuation `+` until we found
 // empty line or non-list line.
 func (docp *documentParser) parseListBlock() (el *element, line []byte) {
 	var ok bool
@@ -810,7 +810,7 @@ func (docp *documentParser) parseListDescription(
 			continue
 		}
 		if docp.kind == elKindListOrderedItem {
-			line = docp.parseListOrdered(listItem, "", line, term)
+			line = docp.parseListOrdered(listItem, ``, line, term)
 			continue
 		}
 		if docp.kind == elKindListUnorderedItem {
@@ -999,7 +999,7 @@ func (docp *documentParser) parseListOrdered(
 				parentListItem = parentListItem.parent
 			}
 
-			line = docp.parseListOrdered(listItem, "", line, term)
+			line = docp.parseListOrdered(listItem, ``, line, term)
 			continue
 		}
 		if docp.kind == elKindListUnorderedItem {
@@ -1234,7 +1234,7 @@ func (docp *documentParser) parseListUnordered(
 				parentListItem = parentListItem.parent
 			}
 
-			line = docp.parseListOrdered(listItem, "", line, term)
+			line = docp.parseListOrdered(listItem, ``, line, term)
 			continue
 		}
 
diff --git a/document_test.go b/document_test.go
index c95aa7c..12a9439 100644
--- a/document_test.go
+++ b/document_test.go
@@ -17,12 +17,12 @@ func TestOpen(t *testing.T) {
 		err  error
 	)
 
-	doc, err = Open("testdata/test.adoc")
+	doc, err = Open(`testdata/test.adoc`)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	fout, err = os.OpenFile("testdata/test.got.html",
+	fout, err = os.OpenFile(`testdata/test.got.html`,
 		os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
 	if err != nil {
 		t.Fatal(err)
@@ -44,38 +44,38 @@ func TestParse_document_title(t *testing.T) {
 	var cases = []testCase{{
 		content: `= Main: sub`,
 		exp: DocumentTitle{
-			Main: "Main",
-			Sub:  "sub",
+			Main: `Main`,
+			Sub:  `sub`,
 			sep:  defTitleSeparator,
 		},
-		expString: "Main: sub",
+		expString: `Main: sub`,
 	}, {
 		// Without space after separator
 		content: `= Main:sub`,
 		exp: DocumentTitle{
-			Main: "Main:sub",
+			Main: `Main:sub`,
 			sep:  defTitleSeparator,
 		},
-		expString: "Main:sub",
+		expString: `Main:sub`,
 	}, {
 		// With multiple separator after separator
 		content: `= a: b: c`,
 		exp: DocumentTitle{
-			Main: "a: b",
-			Sub:  "c",
+			Main: `a: b`,
+			Sub:  `c`,
 			sep:  defTitleSeparator,
 		},
-		expString: "a: b: c",
+		expString: `a: b: c`,
 	}, {
 		// With custom separator.
 		content: `:title-separator: x
 = Mainx sub`,
 		exp: DocumentTitle{
-			Main: "Main",
-			Sub:  "sub",
+			Main: `Main`,
+			Sub:  `sub`,
 			sep:  'x',
 		},
-		expString: "Mainx sub",
+		expString: `Mainx sub`,
 	}}
 
 	var (
@@ -85,9 +85,9 @@ func TestParse_document_title(t *testing.T) {
 
 	for _, c = range cases {
 		got = Parse([]byte(c.content))
-		test.Assert(t, "Main", c.exp.Main, got.Title.Main)
-		test.Assert(t, "Sub", c.exp.Sub, got.Title.Sub)
-		test.Assert(t, "sep", c.exp.sep, got.Title.sep)
-		test.Assert(t, "String", c.expString, got.Title.String())
+		test.Assert(t, `Main`, c.exp.Main, got.Title.Main)
+		test.Assert(t, `Sub`, c.exp.Sub, got.Title.Sub)
+		test.Assert(t, `sep`, c.exp.sep, got.Title.sep)
+		test.Assert(t, `String`, c.expString, got.Title.String())
 	}
 }
diff --git a/document_title.go b/document_title.go
index e646a8a..9312fd4 100644
--- a/document_title.go
+++ b/document_title.go
@@ -16,10 +16,10 @@ type DocumentTitle struct {
 }
 
 // String return the combination of main and subtitle separated by colon or
-// meta "title-separator" value.
+// meta `title-separator` value.
 func (docTitle *DocumentTitle) String() string {
 	if len(docTitle.Sub) > 0 {
-		return fmt.Sprintf("%s%c %s", docTitle.Main, docTitle.sep, docTitle.Sub)
+		return fmt.Sprintf(`%s%c %s`, docTitle.Main, docTitle.sep, docTitle.Sub)
 	}
 	return docTitle.Main
 }
diff --git a/element.go b/element.go
index e757669..46d045d 100644
--- a/element.go
+++ b/element.go
@@ -28,7 +28,7 @@ type element struct {
 	table *elementTable
 
 	// sectnums contain the current section numbers.
-	// It will be set only if attribute "sectnums" is on.
+	// It will be set only if attribute `sectnums` is on.
 	sectnums *sectionCounters
 
 	// The key and value for attribute (lineKindAttribute).
@@ -64,18 +64,18 @@ func (el *element) getListOrderedClass() string {
 func (el *element) getListOrderedType() string {
 	switch el.level {
 	case 2:
-		return "a"
+		return `a`
 	case 3:
-		return "i"
+		return `i`
 	case 4:
-		return "A"
+		return `A`
 	case 5:
-		return "I"
+		return `I`
 	}
-	return ""
+	return ``
 }
 
-// getVideoSource generate video full URL for HTML attribute "src".
+// getVideoSource generate video full URL for HTML attribute `src`.
 func (el *element) getVideoSource() string {
 	var (
 		u          = new(url.URL)
@@ -98,89 +98,89 @@ func (el *element) getVideoSource() string {
 	}
 
 	if isYoutube {
-		u.Scheme = "https"
-		u.Host = "www.youtube.com"
-		u.Path = "/embed/" + src
+		u.Scheme = `https`
+		u.Host = `www.youtube.com`
+		u.Path = `/embed/` + src
 
-		q = append(q, "rel=0")
+		q = append(q, `rel=0`)
 
 		vstr, ok = el.Attrs[attrNameStart]
 		if ok {
-			q = append(q, attrNameStart+"="+vstr)
+			q = append(q, attrNameStart+`=`+vstr)
 		}
 
 		vstr, ok = el.Attrs[attrNameEnd]
 		if ok {
-			q = append(q, attrNameEnd+"="+vstr)
+			q = append(q, attrNameEnd+`=`+vstr)
 		}
 
 		for _, vstr = range el.options {
 			switch vstr {
 			case optNameAutoplay, optNameLoop:
-				q = append(q, vstr+"=1")
+				q = append(q, vstr+`=1`)
 			case optVideoModest:
-				q = append(q, optVideoYoutubeModestbranding+"=1")
+				q = append(q, optVideoYoutubeModestbranding+`=1`)
 			case optNameNocontrols:
-				q = append(q, optNameControls+"=0")
-				q = append(q, optVideoPlaylist+"="+src)
+				q = append(q, optNameControls+`=0`)
+				q = append(q, optVideoPlaylist+`=`+src)
 			case optVideoNofullscreen:
-				q = append(q, optVideoFullscreen+"=0")
-				el.Attrs[optVideoNofullscreen] = ""
+				q = append(q, optVideoFullscreen+`=0`)
+				el.Attrs[optVideoNofullscreen] = ``
 			}
 		}
 
 		vstr, ok = el.Attrs[attrNameTheme]
 		if ok {
-			q = append(q, attrNameTheme+"="+vstr)
+			q = append(q, attrNameTheme+`=`+vstr)
 		}
 
 		vstr, ok = el.Attrs[attrNameLang]
 		if ok {
-			q = append(q, attrNameYoutubeLang+"="+vstr)
+			q = append(q, attrNameYoutubeLang+`=`+vstr)
 		}
 
 	} else if isVimeo {
-		u.Scheme = "https"
-		u.Host = "player.vimeo.com"
-		u.Path = "/video/" + src
+		u.Scheme = `https`
+		u.Host = `player.vimeo.com`
+		u.Path = `/video/` + src
 
 		for _, vstr = range el.options {
 			switch vstr {
 			case optNameAutoplay, optNameLoop:
-				q = append(q, vstr+"=1")
+				q = append(q, vstr+`=1`)
 			}
 		}
 		vstr, ok = el.Attrs[attrNameStart]
 		if ok {
-			fragment = "at=" + vstr
+			fragment = `at=` + vstr
 		}
 
 	} else {
 		for _, vstr = range el.options {
 			switch vstr {
 			case optNameAutoplay, optNameLoop:
-				el.Attrs[optNameNocontrols] = ""
-				el.Attrs[vstr] = ""
+				el.Attrs[optNameNocontrols] = ``
+				el.Attrs[vstr] = ``
 			}
 		}
 
 		vstr, ok = el.Attrs[attrNameStart]
 		if ok {
-			fragment = "t=" + vstr
+			fragment = `t=` + vstr
 			vstr, ok = el.Attrs[attrNameEnd]
 			if ok {
-				fragment += "," + vstr
+				fragment += `,` + vstr
 			}
 		} else if vstr, ok = el.Attrs[attrNameEnd]; ok {
-			fragment = "t=0," + vstr
+			fragment = `t=0,` + vstr
 		}
 
 		if len(fragment) > 0 {
-			src = src + "#" + fragment
+			src = src + `#` + fragment
 		}
 		return src
 	}
-	u.RawQuery = strings.Join(q, "&amp;")
+	u.RawQuery = strings.Join(q, `&amp;`)
 	u.Fragment = fragment
 
 	return u.String()
@@ -222,7 +222,7 @@ func (el *element) WriteString(s string) {
 	el.raw = append(el.raw, []byte(s)...)
 }
 
-// addChild push the "child" to the list of current element's child.
+// addChild push the `child` to the list of current element's child.
 func (el *element) addChild(child *element) {
 	if child == nil {
 		return
@@ -346,7 +346,7 @@ func (el *element) parseBlockImage(doc *Document, line []byte) bool {
 	src = applySubstitutions(doc, src)
 	el.Attrs[attrNameSrc] = string(src)
 
-	attrs = bytes.Split(line[attrBegin+1:attrEnd], []byte(","))
+	attrs = bytes.Split(line[attrBegin+1:attrEnd], []byte(`,`))
 	if el.Attrs == nil {
 		el.Attrs = make(map[string]string)
 	}
@@ -376,7 +376,7 @@ func (el *element) parseBlockImage(doc *Document, line []byte) bool {
 				el.Attrs[attrNameHeight] = string(attrs[2])
 			}
 		}
-		kv = strings.SplitN(attr, "=", 2)
+		kv = strings.SplitN(attr, `=`, 2)
 		if len(kv) != 2 {
 			continue
 		}
@@ -384,8 +384,8 @@ func (el *element) parseBlockImage(doc *Document, line []byte) bool {
 		val = strings.Trim(kv[1], `"`)
 		switch key {
 		case attrNameFloat, attrNameAlign, attrNameRole:
-			if val == "center" {
-				val = "text-center"
+			if val == `center` {
+				val = `text-center`
 			}
 			el.addRole(val)
 		default:
@@ -444,7 +444,7 @@ func (el *element) parseListDescriptionItem(line []byte) {
 		c     byte
 	)
 
-	label, x = indexUnescape(line, []byte("::"))
+	label, x = indexUnescape(line, []byte(`::`))
 	el.rawLabel.Write(label)
 
 	line = line[x+2:]
@@ -523,11 +523,11 @@ func (el *element) parseListUnorderedItem(line []byte) {
 			checklist = line[x : x+3]
 			sym       string
 		)
-		if bytes.Equal(checklist, []byte("[ ]")) {
+		if bytes.Equal(checklist, []byte(`[ ]`)) {
 			sym = symbolUnchecked
-		} else if bytes.Equal(checklist, []byte("[x]")) ||
-			bytes.Equal(checklist, []byte("[X]")) ||
-			bytes.Equal(checklist, []byte("[*]")) {
+		} else if bytes.Equal(checklist, []byte(`[x]`)) ||
+			bytes.Equal(checklist, []byte(`[X]`)) ||
+			bytes.Equal(checklist, []byte(`[*]`)) {
 			sym = symbolChecked
 		}
 		if len(sym) != 0 {
@@ -613,10 +613,10 @@ func (el *element) parseSection(doc *Document, isDiscrete bool) {
 }
 
 func (el *element) parseStyleClass(line []byte) {
-	line = bytes.Trim(line, "[]")
+	line = bytes.Trim(line, `[]`)
 
 	var (
-		parts = bytes.Split(line, []byte("."))
+		parts = bytes.Split(line, []byte(`.`))
 
 		class []byte
 	)
@@ -843,7 +843,7 @@ func (el *element) toHTML(doc *Document, w io.Writer) {
 				label = anchor.label
 			}
 		}
-		fmt.Fprintf(w, "<a href=\"#%s\">%s</a>", href, label)
+		fmt.Fprintf(w, `<a href="#%s">%s</a>`, href, label)
 
 	case elKindMacroTOC:
 		if doc.tocIsEnabled && doc.tocPosition == metaValueMacro {
diff --git a/element_attribute.go b/element_attribute.go
index 5b6de01..d08538d 100644
--- a/element_attribute.go
+++ b/element_attribute.go
@@ -33,12 +33,12 @@ func (ea *elementAttribute) addRole(role string) {
 
 func (ea *elementAttribute) htmlClasses() string {
 	if len(ea.roles) == 0 {
-		return ""
+		return ``
 	}
-	return strings.Join(ea.roles, " ")
+	return strings.Join(ea.roles, ` `)
 }
 
-// parseElementAttribute parse list of attributes in between "[" "]".
+// parseElementAttribute parse list of attributes in between `[` `]`.
 //
 //	BLOCK_ATTRS = BLOCK_ATTR *("," BLOCK_ATTR)
 //
@@ -141,13 +141,13 @@ func (ea *elementAttribute) parseNamedValue(prevc byte, str string) {
 	}
 
 	var (
-		kv  []string = strings.Split(str, "=")
+		kv  []string = strings.Split(str, `=`)
 		key          = kv[0]
 		val          = strings.TrimSpace(kv[1])
 	)
 
 	if len(val) == 0 {
-		ea.Attrs[key] = ""
+		ea.Attrs[key] = ``
 		return
 	}
 	if val[0] == '"' {
@@ -158,7 +158,7 @@ func (ea *elementAttribute) parseNamedValue(prevc byte, str string) {
 	}
 
 	var (
-		rawvals []string = strings.Split(val, ",")
+		rawvals []string = strings.Split(val, `,`)
 		vals             = make([]string, 0, len(rawvals))
 
 		v string
@@ -213,14 +213,14 @@ func (ea *elementAttribute) setByPreviousChar(prevc byte, str string) {
 				case styleSource:
 					ea.Attrs[attrNameSource] = str
 				default:
-					ea.Attrs[str] = ""
+					ea.Attrs[str] = ``
 				}
 			case 2:
 				switch ea.style {
 				case styleQuote, styleVerse:
 					ea.Attrs[attrNameCitation] = str
 				default:
-					ea.Attrs[str] = ""
+					ea.Attrs[str] = ``
 				}
 			}
 		}
diff --git a/element_attribute_test.go b/element_attribute_test.go
index c7b99e8..ef543aa 100644
--- a/element_attribute_test.go
+++ b/element_attribute_test.go
@@ -16,42 +16,42 @@ func Test_parseElementAttribute(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		raw: "",
+		raw: ``,
 	}, {
-		raw: "[]",
+		raw: `[]`,
 	}, {
-		raw: "[STYLE]",
+		raw: `[STYLE]`,
 		exp: elementAttribute{
-			rawStyle: "STYLE",
+			rawStyle: `STYLE`,
 		},
 	}, {
-		raw: "[style#id]",
+		raw: `[style#id]`,
 		exp: elementAttribute{
-			ID:       "id",
-			rawStyle: "style",
+			ID:       `id`,
+			rawStyle: `style`,
 		},
 	}, {
 		raw: `[#id.role1.role2,options="opt1,opt2"]`,
 		exp: elementAttribute{
-			ID:      "id",
-			roles:   []string{"role1", "role2"},
-			options: []string{"opt1", "opt2"},
+			ID:      `id`,
+			roles:   []string{`role1`, `role2`},
+			options: []string{`opt1`, `opt2`},
 			pos:     1,
 		},
 	}, {
 		raw: `[cols="3*,^"]`,
 		exp: elementAttribute{
 			Attrs: map[string]string{
-				attrNameCols: "3*,^",
+				attrNameCols: `3*,^`,
 			},
 		},
 	}, {
 		raw: `[quote, attribution]`,
 		exp: elementAttribute{
 			Attrs: map[string]string{
-				attrNameAttribution: "attribution",
+				attrNameAttribution: `attribution`,
 			},
-			rawStyle: "quote",
+			rawStyle: `quote`,
 			style:    styleQuote,
 			pos:      1,
 		},
@@ -59,10 +59,10 @@ func Test_parseElementAttribute(t *testing.T) {
 		raw: `[quote, attribution, citation]`,
 		exp: elementAttribute{
 			Attrs: map[string]string{
-				attrNameAttribution: "attribution",
-				attrNameCitation:    "citation",
+				attrNameAttribution: `attribution`,
+				attrNameCitation:    `citation`,
 			},
-			rawStyle: "quote",
+			rawStyle: `quote`,
 			style:    styleQuote,
 			pos:      2,
 		},
diff --git a/element_include.go b/element_include.go
index a12ef31..5821359 100644
--- a/element_include.go
+++ b/element_include.go
@@ -48,7 +48,7 @@ func parseInclude(doc *Document, line []byte) (el *elementInclude) {
 
 	el.content, err = os.ReadFile(el.fpath)
 	if err != nil {
-		log.Printf("parseInclude %q: %s", doc.file, err)
+		log.Printf(`parseInclude %q: %s`, doc.file, err)
 		return nil
 	}
 
diff --git a/element_table.go b/element_table.go
index ee389e4..2c0fb42 100644
--- a/element_table.go
+++ b/element_table.go
@@ -132,7 +132,7 @@ func (table *elementTable) initializeClassAndStyles(ea *elementAttribute) {
 				continue
 			}
 			if v[len(v)-1] != '%' {
-				v += "%"
+				v += `%`
 			}
 			table.styles[k] = v
 			withWidth = true
@@ -246,7 +246,7 @@ func (table *elementTable) htmlStyle() string {
 	)
 
 	for k, v = range table.styles {
-		fmt.Fprintf(&buf, "%s: %s;", k, v)
+		fmt.Fprintf(&buf, `%s: %s;`, k, v)
 	}
 	return buf.String()
 }
@@ -269,7 +269,7 @@ func parseAttrCols(val string) (ncols int, formats []*columnFormat) {
 	}
 
 	var (
-		rawFormat = strings.Split(val, ",")
+		rawFormat = strings.Split(val, `,`)
 
 		format      *columnFormat
 		n           int
diff --git a/element_table_test.go b/element_table_test.go
index 42c1bfe..c30e6f1 100644
--- a/element_table_test.go
+++ b/element_table_test.go
@@ -18,7 +18,7 @@ func TestParseAttrCols(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		val:   "3*",
+		val:   `3*`,
 		ncols: 3,
 		formats: []*columnFormat{
 			newColumnFormat(),
@@ -26,7 +26,7 @@ func TestParseAttrCols(t *testing.T) {
 			newColumnFormat(),
 		},
 	}, {
-		val:   "3*^",
+		val:   `3*^`,
 		ncols: 3,
 		formats: []*columnFormat{{
 			alignHor: colAlignMiddle,
@@ -39,7 +39,7 @@ func TestParseAttrCols(t *testing.T) {
 			width:    big.NewRat(1),
 		}},
 	}, {
-		val:   "2*,^",
+		val:   `2*,^`,
 		ncols: 2,
 		formats: []*columnFormat{{
 			width: big.NewRat(1),
@@ -48,7 +48,7 @@ func TestParseAttrCols(t *testing.T) {
 			width:    big.NewRat(1),
 		}},
 	}, {
-		val:   "<,^,>",
+		val:   `<,^,>`,
 		ncols: 3,
 		formats: []*columnFormat{{
 			alignHor: colAlignTop,
@@ -61,7 +61,7 @@ func TestParseAttrCols(t *testing.T) {
 			width:    big.NewRat(1),
 		}},
 	}, {
-		val:   "3*.^",
+		val:   `3*.^`,
 		ncols: 3,
 		formats: []*columnFormat{{
 			alignVer: colAlignMiddle,
@@ -74,7 +74,7 @@ func TestParseAttrCols(t *testing.T) {
 			width:    big.NewRat(1),
 		}},
 	}, {
-		val:   "2*,.>",
+		val:   `2*,.>`,
 		ncols: 2,
 		formats: []*columnFormat{{
 			width: big.NewRat(1),
@@ -83,7 +83,7 @@ func TestParseAttrCols(t *testing.T) {
 			width:    big.NewRat(1),
 		}},
 	}, {
-		val:   ".<,.^,.>",
+		val:   `.<,.^,.>`,
 		ncols: 3,
 		formats: []*columnFormat{{
 			alignVer: colAlignTop,
@@ -96,7 +96,7 @@ func TestParseAttrCols(t *testing.T) {
 			width:    big.NewRat(1),
 		}},
 	}, {
-		val:   ".<,.^,^.>",
+		val:   `.<,.^,^.>`,
 		ncols: 3,
 		formats: []*columnFormat{{
 			alignVer: colAlignTop,
@@ -110,7 +110,7 @@ func TestParseAttrCols(t *testing.T) {
 			width:    big.NewRat(1),
 		}},
 	}, {
-		val:   "1,2,6",
+		val:   `1,2,6`,
 		ncols: 3,
 		formats: []*columnFormat{{
 			width: big.NewRat(1),
@@ -120,7 +120,7 @@ func TestParseAttrCols(t *testing.T) {
 			width: big.NewRat(6),
 		}},
 	}, {
-		val:   "50,20,30",
+		val:   `50,20,30`,
 		ncols: 3,
 		formats: []*columnFormat{{
 			width: big.NewRat(50),
@@ -130,7 +130,7 @@ func TestParseAttrCols(t *testing.T) {
 			width: big.NewRat(30),
 		}},
 	}, {
-		val:   ".<2,.^5,^.>3",
+		val:   `.<2,.^5,^.>3`,
 		ncols: 3,
 		formats: []*columnFormat{{
 			alignVer: colAlignTop,
@@ -144,7 +144,7 @@ func TestParseAttrCols(t *testing.T) {
 			width:    big.NewRat(3),
 		}},
 	}, {
-		val:   "h,m,s,e",
+		val:   `h,m,s,e`,
 		ncols: 4,
 		formats: []*columnFormat{{
 			style: colStyleHeader,
@@ -169,7 +169,7 @@ func TestParseAttrCols(t *testing.T) {
 
 	for _, c = range cases {
 		ncols, formats = parseAttrCols(c.val)
-		test.Assert(t, "ncols", c.ncols, ncols)
+		test.Assert(t, `ncols`, c.ncols, ncols)
 		test.Assert(t, c.val, c.formats, formats)
 	}
 }
@@ -182,49 +182,49 @@ func TestParseToRawRows(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		desc: "empty content",
+		desc: `empty content`,
 		raw:  ``,
 		exp:  make([][]byte, 1),
 	}, {
-		desc: "empty content with no header",
+		desc: `empty content with no header`,
 		raw: `
 `,
 		exp: make([][]byte, 2),
 	}, {
-		desc: "header only",
+		desc: `header only`,
 		raw:  `A | B`,
 		exp: [][]byte{
-			[]byte("A | B"),
+			[]byte(`A | B`),
 		},
 	}, {
-		desc: "without header",
+		desc: `without header`,
 		raw: `
 | A`,
 		exp: [][]byte{
 			nil,
-			[]byte("| A"),
+			[]byte(`| A`),
 		},
 	}, {
-		desc: "header and one row",
+		desc: `header and one row`,
 		raw: `A
 | B
 
 | C`,
 		exp: [][]byte{
-			[]byte("A"),
-			[]byte("| B"),
+			[]byte(`A`),
+			[]byte(`| B`),
 			nil,
-			[]byte("| C"),
+			[]byte(`| C`),
 		},
 	}, {
-		desc: "with no header, consecutive rows",
+		desc: `with no header, consecutive rows`,
 		raw: `
 | A | B
 | C | D`,
 		exp: [][]byte{
 			nil,
-			[]byte("| A | B"),
-			[]byte("| C | D"),
+			[]byte(`| A | B`),
+			[]byte(`| C | D`),
 		},
 	}}
 
diff --git a/element_test.go b/element_test.go
index 58ce598..e252db7 100644
--- a/element_test.go
+++ b/element_test.go
@@ -19,9 +19,9 @@ func TestAdocNode_parseListDescriptionItem(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		line:       "CPU::",
+		line:       `CPU::`,
 		expLevel:   0,
-		expRawTerm: "CPU",
+		expRawTerm: `CPU`,
 	}}
 
 	var (
@@ -33,9 +33,9 @@ func TestAdocNode_parseListDescriptionItem(t *testing.T) {
 		el = &element{}
 		el.parseListDescriptionItem([]byte(c.line))
 
-		test.Assert(t, "element.Level", c.expLevel, el.level)
-		test.Assert(t, "element.rawLabel", c.expRawTerm, el.rawLabel.String())
-		test.Assert(t, "element.raw", c.expRaw, string(el.raw))
+		test.Assert(t, `element.Level`, c.expLevel, el.level)
+		test.Assert(t, `element.rawLabel`, c.expRawTerm, el.rawLabel.String())
+		test.Assert(t, `element.raw`, c.expRaw, string(el.raw))
 	}
 }
 
@@ -49,35 +49,35 @@ func TestElement_parseListUnorderedItem(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		desc:     "With text",
+		desc:     `With text`,
 		line:     []byte("* \t a"),
 		expRaw:   []byte("a\n"),
 		expLevel: 1,
 	}, {
-		desc:     "With unchecked box, no text",
-		line:     []byte("* [ ]"),
+		desc:     `With unchecked box, no text`,
+		line:     []byte(`* [ ]`),
 		expRaw:   []byte("[ ]\n"),
 		expLevel: 1,
 	}, {
-		desc:     "With unchecked box",
+		desc:     `With unchecked box`,
 		line:     []byte("* [ ] \t a"),
 		expRaw:   []byte("&#10063; a\n"),
 		expRoles: []string{classNameChecklist},
 		expLevel: 1,
 	}, {
-		desc:     "With checked box, using 'x'",
+		desc:     `With checked box, using 'x'`,
 		line:     []byte("* [x] \t a"),
 		expRaw:   []byte("&#10003; a\n"),
 		expRoles: []string{classNameChecklist},
 		expLevel: 1,
 	}, {
-		desc:     "With checked box, using 'X'",
+		desc:     `With checked box, using 'X'`,
 		line:     []byte("* [X] \t a"),
 		expRaw:   []byte("&#10003; a\n"),
 		expRoles: []string{classNameChecklist},
 		expLevel: 1,
 	}, {
-		desc:     "With checked box, using '*'",
+		desc:     `With checked box, using '*'`,
 		line:     []byte("* [*] \t a"),
 		expRaw:   []byte("&#10003; a\n"),
 		expRoles: []string{classNameChecklist},
@@ -94,9 +94,9 @@ func TestElement_parseListUnorderedItem(t *testing.T) {
 		el.raw = el.raw[:0]
 		el.parseListUnorderedItem(c.line)
 
-		test.Assert(t, c.desc+" - level", c.expLevel, el.level)
-		test.Assert(t, c.desc+" - roles", c.expRoles, el.roles)
-		test.Assert(t, c.desc+" - raw", c.expRaw, el.raw)
+		test.Assert(t, c.desc+` - level`, c.expLevel, el.level)
+		test.Assert(t, c.desc+` - roles`, c.expRoles, el.roles)
+		test.Assert(t, c.desc+` - raw`, c.expRaw, el.raw)
 	}
 }
 
@@ -108,7 +108,7 @@ func TestAdocNode_postConsumeTable(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		desc: "single row, multiple lines",
+		desc: `single row, multiple lines`,
 		raw:  "|A\n|B",
 		exp: elementTable{
 			ncols: 2,
@@ -122,7 +122,7 @@ func TestAdocNode_postConsumeTable(t *testing.T) {
 				cells: []*tableCell{{
 					content: []byte("A\n"),
 				}, {
-					content: []byte("B"),
+					content: []byte(`B`),
 				}},
 				ncell: 2,
 			}},
@@ -144,7 +144,7 @@ func TestAdocNode_postConsumeTable(t *testing.T) {
 			hasHeader: false,
 		},
 	}, {
-		desc: "with header",
+		desc: `with header`,
 		raw:  "A1|B1\n\n|A2\n|B2",
 		exp: elementTable{
 			ncols: 2,
@@ -156,16 +156,16 @@ func TestAdocNode_postConsumeTable(t *testing.T) {
 			},
 			rows: []*tableRow{{
 				cells: []*tableCell{{
-					content: []byte("A1"),
+					content: []byte(`A1`),
 				}, {
-					content: []byte("B1"),
+					content: []byte(`B1`),
 				}},
 				ncell: 2,
 			}, {
 				cells: []*tableCell{{
 					content: []byte("A2\n"),
 				}, {
-					content: []byte("B2"),
+					content: []byte(`B2`),
 				}},
 				ncell: 2,
 			}},
@@ -187,7 +187,7 @@ func TestAdocNode_postConsumeTable(t *testing.T) {
 			hasHeader: true,
 		},
 	}, {
-		desc: "with multiple rows",
+		desc: `with multiple rows`,
 		raw:  "A|B|\n\n|r1c1\n|r1c2|\n\n|r2c1 | r2c2",
 		exp: elementTable{
 			ncols: 3,
@@ -199,39 +199,39 @@ func TestAdocNode_postConsumeTable(t *testing.T) {
 			},
 			rows: []*tableRow{{
 				cells: []*tableCell{{
-					content: []byte("A"),
+					content: []byte(`A`),
 				}, {
-					content: []byte("B"),
+					content: []byte(`B`),
 				}, {
-					content: []byte(""),
+					content: []byte(``),
 				}},
 				ncell: 3,
 			}, {
 				cells: []*tableCell{{
 					content: []byte("r1c1\n"),
 				}, {
-					content: []byte("r1c2"),
+					content: []byte(`r1c2`),
 				}, {
-					content: []byte(""),
+					content: []byte(``),
 				}},
 				ncell: 3,
 			}},
 			formats: []*columnFormat{{
-				width: big.NewRat("33.3333"),
+				width: big.NewRat(`33.3333`),
 				classes: []string{
 					classNameTableBlock,
 					classNameHalignLeft,
 					classNameValignTop,
 				},
 			}, {
-				width: big.NewRat("33.3333"),
+				width: big.NewRat(`33.3333`),
 				classes: []string{
 					classNameTableBlock,
 					classNameHalignLeft,
 					classNameValignTop,
 				},
 			}, {
-				width: big.NewRat("33.3334"),
+				width: big.NewRat(`33.3334`),
 				classes: []string{
 					classNameTableBlock,
 					classNameHalignLeft,
diff --git a/html_backend.go b/html_backend.go
index 51a905f..e631448 100644
--- a/html_backend.go
+++ b/html_backend.go
@@ -13,51 +13,51 @@ import (
 )
 
 const (
-	classNameArticle      = "article"
-	classNameHalignCenter = "halign-center"
-	classNameHalignLeft   = "halign-left"
-	classNameHalignRight  = "halign-right"
-	classNameListingBlock = "listingblock"
-	classNameLiteral      = "literal"
-	classNameLiteralBlock = "literalblock"
-	classNameTableBlock   = "tableblock"
-	classNameToc          = "toc"
-	classNameToc2         = "toc2"
-	classNameTocLeft      = "toc-left"
-	classNameTocRight     = "toc-right"
-	classNameUlist        = "ulist"
-	classNameValignBottom = "valign-bottom"
-	classNameValignMiddle = "valign-middle"
-	classNameValignTop    = "valign-top"
+	classNameArticle      = `article`
+	classNameHalignCenter = `halign-center`
+	classNameHalignLeft   = `halign-left`
+	classNameHalignRight  = `halign-right`
+	classNameListingBlock = `listingblock`
+	classNameLiteral      = `literal`
+	classNameLiteralBlock = `literalblock`
+	classNameTableBlock   = `tableblock`
+	classNameToc          = `toc`
+	classNameToc2         = `toc2`
+	classNameTocLeft      = `toc-left`
+	classNameTocRight     = `toc-right`
+	classNameUlist        = `ulist`
+	classNameValignBottom = `valign-bottom`
+	classNameValignMiddle = `valign-middle`
+	classNameValignTop    = `valign-top`
 )
 
 const (
-	htmlSymbolAmpersand         = "&amp;"
-	htmlSymbolApostrophe        = "&#8217;"
-	htmlSymbolBrokenVerticalBar = "&#166;"
-	htmlSymbolCopyright         = "&#169;"
-	htmlSymbolDegreeSign        = "&#176;"
-	htmlSymbolDoubleLeftArrow   = "&#8656;"
-	htmlSymbolDoubleQuote       = "&#34;"
-	htmlSymbolDoubleRightArrow  = "&#8658;"
-	htmlSymbolEllipsis          = "&#8230;"
-	htmlSymbolEmdash            = "&#8212;"
-	htmlSymbolGreaterthan       = "&gt;"
-	htmlSymbolLeftDoubleQuote   = "&#8220;"
-	htmlSymbolLeftSingleQuote   = "&#8216;"
-	htmlSymbolLessthan          = "&lt;"
-	htmlSymbolNonBreakingSpace  = "&#160;"
-	htmlSymbolPlus              = "&#43;"
-	htmlSymbolRegistered        = "&#174;"
-	htmlSymbolRightDoubleQuote  = "&#8221;"
-	htmlSymbolRightSingleQuote  = "&#8217;"
-	htmlSymbolSingleLeftArrow   = "&#8592;"
-	htmlSymbolSingleQuote       = "&#39;"
-	htmlSymbolSingleRightArrow  = "&#8594;"
-	htmlSymbolThinSpace         = "&#8201;"
-	htmlSymbolTrademark         = "&#8482;"
-	htmlSymbolWordJoiner        = "&#8288;"
-	htmlSymbolZeroWidthSpace    = "&#8203;"
+	htmlSymbolAmpersand         = `&amp;`
+	htmlSymbolApostrophe        = `&#8217;`
+	htmlSymbolBrokenVerticalBar = `&#166;`
+	htmlSymbolCopyright         = `&#169;`
+	htmlSymbolDegreeSign        = `&#176;`
+	htmlSymbolDoubleLeftArrow   = `&#8656;`
+	htmlSymbolDoubleQuote       = `&#34;`
+	htmlSymbolDoubleRightArrow  = `&#8658;`
+	htmlSymbolEllipsis          = `&#8230;`
+	htmlSymbolEmdash            = `&#8212;`
+	htmlSymbolGreaterthan       = `&gt;`
+	htmlSymbolLeftDoubleQuote   = `&#8220;`
+	htmlSymbolLeftSingleQuote   = `&#8216;`
+	htmlSymbolLessthan          = `&lt;`
+	htmlSymbolNonBreakingSpace  = `&#160;`
+	htmlSymbolPlus              = `&#43;`
+	htmlSymbolRegistered        = `&#174;`
+	htmlSymbolRightDoubleQuote  = `&#8221;`
+	htmlSymbolRightSingleQuote  = `&#8217;`
+	htmlSymbolSingleLeftArrow   = `&#8592;`
+	htmlSymbolSingleQuote       = `&#39;`
+	htmlSymbolSingleRightArrow  = `&#8594;`
+	htmlSymbolThinSpace         = `&#8201;`
+	htmlSymbolTrademark         = `&#8482;`
+	htmlSymbolWordJoiner        = `&#8288;`
+	htmlSymbolZeroWidthSpace    = `&#8203;`
 )
 
 func htmlWriteBlockBegin(el *element, out io.Writer, addClass string) {
@@ -69,13 +69,13 @@ func htmlWriteBlockBegin(el *element, out io.Writer, addClass string) {
 
 	var (
 		classes string = el.htmlClasses()
-		c       string = strings.TrimSpace(addClass + " " + classes)
+		c       string = strings.TrimSpace(addClass + ` ` + classes)
 	)
 
 	if len(c) > 0 {
 		fmt.Fprintf(out, ` class="%s">`, c)
 	} else {
-		fmt.Fprint(out, ">")
+		fmt.Fprint(out, `>`)
 	}
 
 	if !(el.isStyleAdmonition() ||
@@ -90,7 +90,7 @@ func htmlWriteBlockBegin(el *element, out io.Writer, addClass string) {
 }
 
 func htmlWriteBlockAdmonition(el *element, out io.Writer) {
-	htmlWriteBlockBegin(el, out, "admonitionblock")
+	htmlWriteBlockBegin(el, out, `admonitionblock`)
 
 	fmt.Fprint(out, "\n<table>\n<tr>\n<td class=\"icon\">")
 
@@ -116,32 +116,32 @@ func htmlWriteBlockAdmonition(el *element, out io.Writer) {
 
 func htmlWriteBlockAudio(el *element, out io.Writer) {
 	var (
-		optControls string = " controls"
+		optControls string = ` controls`
 		src         string = el.Attrs[attrNameSrc]
 
 		optAutoplay string
 		optLoop     string
 	)
 
-	htmlWriteBlockBegin(el, out, "audioblock")
+	htmlWriteBlockBegin(el, out, `audioblock`)
 
 	fmt.Fprintf(out, "\n<div class=%q>", attrValueContent)
 
 	if libstrings.IsContain(el.options, optNameAutoplay) {
-		optAutoplay = " autoplay"
+		optAutoplay = ` autoplay`
 	}
 	if libstrings.IsContain(el.options, optNameNocontrols) {
-		optControls = ""
+		optControls = ``
 	}
 	if libstrings.IsContain(el.options, optNameLoop) {
-		optLoop = " loop"
+		optLoop = ` loop`
 	}
 
 	fmt.Fprintf(out, _htmlBlockAudio, src, optAutoplay, optControls, optLoop)
 }
 
 func htmlWriteBlockExample(doc *Document, el *element, out io.Writer) {
-	htmlWriteBlockBegin(el, out, "exampleblock")
+	htmlWriteBlockBegin(el, out, `exampleblock`)
 	if len(el.rawTitle) > 0 {
 		doc.counterExample++
 		fmt.Fprintf(out, "\n<div class=%q>Example %d. %s</div>",
@@ -151,7 +151,7 @@ func htmlWriteBlockExample(doc *Document, el *element, out io.Writer) {
 }
 
 func htmlWriteBlockImage(doc *Document, el *element, out io.Writer) {
-	htmlWriteBlockBegin(el, out, "imageblock")
+	htmlWriteBlockBegin(el, out, `imageblock`)
 
 	var (
 		src = el.Attrs[attrNameSrc]
@@ -184,7 +184,7 @@ func htmlWriteBlockImage(doc *Document, el *element, out io.Writer) {
 }
 
 func htmlWriteBlockLiteral(el *element, out io.Writer) {
-	htmlWriteBlockBegin(el, out, "")
+	htmlWriteBlockBegin(el, out, ``)
 
 	var (
 		source string
@@ -193,7 +193,7 @@ func htmlWriteBlockLiteral(el *element, out io.Writer) {
 	)
 	source, ok = el.Attrs[attrNameSource]
 	if ok {
-		class = "language-" + source
+		class = `language-` + source
 		fmt.Fprint(out, "\n<div class=\"content\">\n<pre class=\"highlight\">")
 		fmt.Fprintf(out, `<code class=%q data-lang=%q>%s</code></pre>`,
 			class, source, el.raw)
@@ -209,7 +209,7 @@ func htmlWriteBlockOpenBegin(el *element, out io.Writer) {
 }
 
 func htmlWriteBlockQuote(el *element, out io.Writer) {
-	htmlWriteBlockBegin(el, out, "quoteblock")
+	htmlWriteBlockBegin(el, out, `quoteblock`)
 	fmt.Fprintf(out, "\n<blockquote>\n%s", el.raw)
 }
 
@@ -235,7 +235,7 @@ func htmlWriteBlockQuoteEnd(el *element, out io.Writer) {
 }
 
 func htmlWriteBlockSidebar(el *element, out io.Writer) {
-	htmlWriteBlockBegin(el, out, "sidebarblock")
+	htmlWriteBlockBegin(el, out, `sidebarblock`)
 	fmt.Fprintf(out, "\n<div class=%q>", attrValueContent)
 	if len(el.rawTitle) > 0 {
 		fmt.Fprintf(out, "\n<div class=%q>%s</div>", attrValueTitle,
@@ -244,12 +244,12 @@ func htmlWriteBlockSidebar(el *element, out io.Writer) {
 }
 
 func htmlWriteBlockVerse(el *element, out io.Writer) {
-	htmlWriteBlockBegin(el, out, "verseblock")
+	htmlWriteBlockBegin(el, out, `verseblock`)
 	fmt.Fprintf(out, "\n<pre class=%q>%s", attrValueContent, el.raw)
 }
 
 func htmlWriteBlockVerseEnd(el *element, out io.Writer) {
-	fmt.Fprint(out, "</pre>")
+	fmt.Fprint(out, `</pre>`)
 
 	var (
 		v  string
@@ -299,7 +299,7 @@ func htmlWriteBlockVideo(el *element, out io.Writer) {
 		isVimeo = true
 	}
 
-	htmlWriteBlockBegin(el, out, "videoblock")
+	htmlWriteBlockBegin(el, out, `videoblock`)
 
 	fmt.Fprintf(out, "\n<div class=%q>", attrValueContent)
 
@@ -311,14 +311,14 @@ func htmlWriteBlockVideo(el *element, out io.Writer) {
 
 		optFullscreen, noFullscreen = el.Attrs[optVideoNofullscreen]
 		if !noFullscreen {
-			optFullscreen = " allowfullscreen"
+			optFullscreen = ` allowfullscreen`
 		}
 		fmt.Fprintf(out, _htmlBlockVideoYoutube, width, height, src, optFullscreen)
 	} else if isVimeo {
 		fmt.Fprintf(out, _htmlBlockVideoVimeo, width, height, src)
 	} else {
 		var (
-			optControls = " controls"
+			optControls = ` controls`
 
 			optAutoplay string
 			optLoop     string
@@ -332,13 +332,13 @@ func htmlWriteBlockVideo(el *element, out io.Writer) {
 		}
 
 		if libstrings.IsContain(el.options, optNameNocontrols) {
-			optControls = ""
+			optControls = ``
 		}
 		if libstrings.IsContain(el.options, optNameAutoplay) {
-			optAutoplay = " autoplay"
+			optAutoplay = ` autoplay`
 		}
 		if libstrings.IsContain(el.options, optNameLoop) {
-			optLoop = " loop"
+			optLoop = ` loop`
 		}
 
 		fmt.Fprintf(out, _htmlBlockVideo, src, width,
@@ -378,9 +378,9 @@ func htmlWriteFooter(doc *Document, out io.Writer) {
 
 		prefix, ok = doc.Attributes[metaNameVersionLabel]
 		if ok && len(prefix) == 0 {
-			prefix = "Version "
+			prefix = `Version `
 		} else {
-			prefix = " "
+			prefix = ` `
 		}
 
 		fmt.Fprintf(out, "\n%s%s<br>", prefix, doc.Revision.Number)
@@ -422,8 +422,8 @@ func htmlWriteHeader(doc *Document, out io.Writer) {
 			authorID = attrValueAuthor
 			emailID = attrValueEmail
 		} else {
-			authorID = fmt.Sprintf("%s%d", attrValueAuthor, x+1)
-			emailID = fmt.Sprintf("%s%d", attrValueEmail, x+1)
+			authorID = fmt.Sprintf(`%s%d`, attrValueAuthor, x+1)
+			emailID = fmt.Sprintf(`%s%d`, attrValueEmail, x+1)
 		}
 
 		fmt.Fprintf(out, "\n<span id=%q class=%q>%s</span><br>",
@@ -441,12 +441,12 @@ func htmlWriteHeader(doc *Document, out io.Writer) {
 		if ok && len(prefix) == 0 {
 			prefix = defVersionPrefix
 		} else {
-			prefix = " "
+			prefix = ` `
 		}
 
-		sep = ""
+		sep = ``
 		if len(doc.Revision.Date) > 0 {
-			sep = ","
+			sep = `,`
 		}
 
 		fmt.Fprintf(out, "\n<span id=%q>%s%s%s</span>",
@@ -462,7 +462,7 @@ func htmlWriteHeader(doc *Document, out io.Writer) {
 	}
 	fmt.Fprint(out, "\n</div>")
 
-	if doc.tocIsEnabled && (doc.tocPosition == "" ||
+	if doc.tocIsEnabled && (doc.tocPosition == `` ||
 		doc.tocPosition == metaValueAuto ||
 		doc.tocPosition == metaValueLeft ||
 		doc.tocPosition == metaValueRight) {
@@ -473,16 +473,16 @@ func htmlWriteHeader(doc *Document, out io.Writer) {
 
 func htmlWriteInlineImage(el *element, out io.Writer) {
 	var (
-		classes = strings.TrimSpace("image " + el.htmlClasses())
+		classes = strings.TrimSpace(`image ` + el.htmlClasses())
 
 		link     string
 		withLink bool
 	)
 
-	fmt.Fprintf(out, "<span class=%q>", classes)
+	fmt.Fprintf(out, `<span class=%q>`, classes)
 	link, withLink = el.Attrs[attrNameLink]
 	if withLink {
-		fmt.Fprintf(out, "<a class=%q href=%q>", attrValueImage, link)
+		fmt.Fprintf(out, `<a class=%q href=%q>`, attrValueImage, link)
 	}
 
 	var (
@@ -503,7 +503,7 @@ func htmlWriteInlineImage(el *element, out io.Writer) {
 		height = fmt.Sprintf(` height="%s"`, height)
 	}
 
-	fmt.Fprintf(out, "<img src=%q alt=%q%s%s>", src, alt, width, height)
+	fmt.Fprintf(out, `<img src=%q alt=%q%s%s>`, src, alt, width, height)
 
 	if withLink {
 		fmt.Fprint(out, `</a>`)
@@ -515,13 +515,13 @@ func htmlWriteInlineImage(el *element, out io.Writer) {
 func htmlWriteListDescription(el *element, out io.Writer) {
 	var openTag string
 	if el.isStyleQandA() {
-		htmlWriteBlockBegin(el, out, "qlist qanda")
+		htmlWriteBlockBegin(el, out, `qlist qanda`)
 		openTag = "\n<ol>"
 	} else if el.isStyleHorizontal() {
-		htmlWriteBlockBegin(el, out, "hdlist")
+		htmlWriteBlockBegin(el, out, `hdlist`)
 		openTag = "\n<table>"
 	} else {
-		htmlWriteBlockBegin(el, out, "dlist")
+		htmlWriteBlockBegin(el, out, `dlist`)
 		openTag = "\n<dl>"
 	}
 
diff --git a/inline_parser.go b/inline_parser.go
index 5fec3b3..62287bf 100644
--- a/inline_parser.go
+++ b/inline_parser.go
@@ -159,7 +159,7 @@ func (pi *inlineParser) do() {
 			}
 			if pi.nextc == '*' {
 				if pi.parseFormatUnconstrained(
-					[]byte("**"),
+					[]byte(`**`),
 					elKindUnconstrainedBold,
 					elKindTextBold,
 					styleTextBold) {
@@ -176,7 +176,7 @@ func (pi *inlineParser) do() {
 			}
 			if pi.nextc == '_' {
 				if pi.parseFormatUnconstrained(
-					[]byte("__"),
+					[]byte(`__`),
 					elKindUnconstrainedItalic,
 					elKindTextItalic,
 					styleTextItalic) {
@@ -365,7 +365,7 @@ func (pi *inlineParser) do() {
 					isReplaced = true
 				}
 			} else if len(vbytes) == 2 {
-				if bytes.Equal(vbytes, []byte("TM")) {
+				if bytes.Equal(vbytes, []byte(`TM`)) {
 					pi.current.WriteString(htmlSymbolTrademark)
 					isReplaced = true
 				}
@@ -417,7 +417,7 @@ func (pi *inlineParser) parseCrossRef() bool {
 		idx int
 	)
 
-	raw, idx = indexUnescape(raw, []byte(">>"))
+	raw, idx = indexUnescape(raw, []byte(`>>`))
 	if idx < 0 {
 		return false
 	}
@@ -430,7 +430,7 @@ func (pi *inlineParser) parseCrossRef() bool {
 		parts      [][]byte
 	)
 
-	parts = bytes.Split(raw, []byte(","))
+	parts = bytes.Split(raw, []byte(`,`))
 	href = string(parts[0])
 	if len(parts) >= 2 {
 		label = string(bytes.TrimSpace(parts[1]))
@@ -513,7 +513,7 @@ func (pi *inlineParser) parseInlineIDShort() bool {
 	)
 
 	// Check if we have term at the end.
-	id, idx = indexUnescape(raw, []byte("]#"))
+	id, idx = indexUnescape(raw, []byte(`]#`))
 	if idx < 0 {
 		return false
 	}
@@ -528,7 +528,7 @@ func (pi *inlineParser) parseInlineIDShort() bool {
 		return false
 	}
 
-	stringID = pi.doc.registerAnchor(string(id), "")
+	stringID = pi.doc.registerAnchor(string(id), ``)
 
 	el = &element{
 		elementAttribute: elementAttribute{
@@ -736,7 +736,7 @@ func (pi *inlineParser) parseMacro() bool {
 	}
 
 	switch name {
-	case "":
+	case ``:
 		return false
 	case macroFTP, macroHTTPS, macroHTTP, macroIRC, macroLink, macroMailto:
 		el = pi.parseURL(name)
@@ -859,7 +859,7 @@ func (pi *inlineParser) parsePassthroughTriple() bool {
 	)
 
 	// Check if we have "+++" at the end.
-	raw, idx = indexUnescape(raw, []byte("+++"))
+	raw, idx = indexUnescape(raw, []byte(`+++`))
 	if idx >= 0 {
 		el = &element{
 			kind: elKindPassthroughTriple,
diff --git a/inline_parser_test.go b/inline_parser_test.go
index 9da5a93..c26b209 100644
--- a/inline_parser_test.go
+++ b/inline_parser_test.go
@@ -62,22 +62,22 @@ func TestInlineParser_parseAttrRef(t *testing.T) {
 
 	var _testDoc = &Document{
 		Attributes: map[string]string{
-			"x": "https://kilabit.info",
+			`x`: `https://kilabit.info`,
 		},
 	}
 
 	var cases = []testCase{{
-		content: "A {x}[*B*] C",
+		content: `A {x}[*B*] C`,
 		exp:     `A <a href="https://kilabit.info"><strong>B</strong></a> C`,
 	}, {
-		content: "A {x }[*B*] C",
+		content: `A {x }[*B*] C`,
 		exp:     `A <a href="https://kilabit.info"><strong>B</strong></a> C`,
 	}, {
-		content: "A {x }*B* C",
+		content: `A {x }*B* C`,
 		exp:     `A <a href="https://kilabit.info*B*" class="bare">https://kilabit.info*B*</a> C`,
 	}, {
-		content: "A {y }*B* C",
-		exp:     "A {y }<strong>B</strong> C",
+		content: `A {y }*B* C`,
+		exp:     `A {y }<strong>B</strong> C`,
 	}}
 
 	var (
@@ -110,26 +110,26 @@ func TestInlineParser_parseCrossReference(t *testing.T) {
 
 	var _testDoc = &Document{
 		anchors: map[string]*anchor{
-			"x": &anchor{
-				label: "X y",
+			`x`: &anchor{
+				label: `X y`,
 			},
 		},
 		titleID: map[string]string{
-			"X y": "x",
+			`X y`: `x`,
 		},
 	}
 
 	var cases = []testCase{{
-		content: "A <<x>>",
+		content: `A <<x>>`,
 		exp:     `A <a href="#x">X y</a>`,
 	}, {
-		content: "A <<x, Label>>",
+		content: `A <<x, Label>>`,
 		exp:     `A <a href="#x">Label</a>`,
 	}, {
-		content: "A <<X y>>",
+		content: `A <<X y>>`,
 		exp:     `A <a href="#x">X y</a>`,
 	}, {
-		content: "A <<X y,Label>>",
+		content: `A <<X y,Label>>`,
 		exp:     `A <a href="#x">Label</a>`,
 	}}
 
@@ -166,29 +166,29 @@ func TestInlineParser_parseFormat(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		content: "_A_B",
-		exp:     "_A_B",
+		content: `_A_B`,
+		exp:     `_A_B`,
 	}, {
-		content: "_A_ B",
-		exp:     "<em>A</em> B",
+		content: `_A_ B`,
+		exp:     `<em>A</em> B`,
 	}, {
-		content: "_A _B",
-		exp:     "_A _B",
+		content: `_A _B`,
+		exp:     `_A _B`,
 	}, {
-		content: "*A*B",
-		exp:     "*A*B",
+		content: `*A*B`,
+		exp:     `*A*B`,
 	}, {
-		content: "*A* B",
-		exp:     "<strong>A</strong> B",
+		content: `*A* B`,
+		exp:     `<strong>A</strong> B`,
 	}, {
-		content: "*A *B",
-		exp:     "*A *B",
+		content: `*A *B`,
+		exp:     `*A *B`,
 	}, {
 		content: "`A`B",
 		exp:     "`A`B",
 	}, {
 		content: "`A` B",
-		exp:     "<code>A</code> B",
+		exp:     `<code>A</code> B`,
 	}, {
 		content: "`A `B",
 		exp:     "`A `B",
@@ -231,23 +231,23 @@ func TestInlineParser_parseFormatUnconstrained(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		content: "__A__B",
-		exp:     "<em>A</em>B",
+		content: `__A__B`,
+		exp:     `<em>A</em>B`,
 	}, {
-		content: "__A *B*__",
-		exp:     "<em>A <strong>B</strong></em>",
+		content: `__A *B*__`,
+		exp:     `<em>A <strong>B</strong></em>`,
 	}, {
-		content: "__A _B_ C__",
-		exp:     "<em>A <em>B</em> C</em>",
+		content: `__A _B_ C__`,
+		exp:     `<em>A <em>B</em> C</em>`,
 	}, {
-		content: "__A B_ C__",
-		exp:     "<em>A B_ C</em>",
+		content: `__A B_ C__`,
+		exp:     `<em>A B_ C</em>`,
 	}, {
-		content: "__A *B*_",
-		exp:     "<em>_A <strong>B</strong></em>",
+		content: `__A *B*_`,
+		exp:     `<em>_A <strong>B</strong></em>`,
 	}, {
-		content: "_A *B*__",
-		exp:     "<em>A <strong>B</strong>_</em>",
+		content: `_A *B*__`,
+		exp:     `<em>A <strong>B</strong>_</em>`,
 	}}
 
 	var (
@@ -724,20 +724,20 @@ func TestInlineParser_parseSuperscript(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		content: "A^B^C",
-		exp:     "A<sup>B</sup>C",
+		content: `A^B^C`,
+		exp:     `A<sup>B</sup>C`,
 	}, {
-		content: "A^B ^C",
-		exp:     "A^B ^C",
+		content: `A^B ^C`,
+		exp:     `A^B ^C`,
 	}, {
-		content: "A^ B^C",
-		exp:     "A^ B^C",
+		content: `A^ B^C`,
+		exp:     `A^ B^C`,
 	}, {
 		content: `A\^B^C`,
-		exp:     "A^B^C",
+		exp:     `A^B^C`,
 	}, {
 		content: `A^B\^C`,
-		exp:     "A^B^C",
+		exp:     `A^B^C`,
 	}}
 
 	var (
diff --git a/parser.go b/parser.go
index 8ab2f47..a210069 100644
--- a/parser.go
+++ b/parser.go
@@ -11,13 +11,13 @@ import (
 )
 
 const (
-	macroFTP    = "ftp"
-	macroHTTP   = "http"
-	macroHTTPS  = "https"
-	macroIRC    = "irc"
-	macroImage  = "image"
-	macroLink   = "link"
-	macroMailto = "mailto"
+	macroFTP    = `ftp`
+	macroHTTP   = `http`
+	macroHTTPS  = `https`
+	macroIRC    = `irc`
+	macroImage  = `image`
+	macroLink   = `link`
+	macroMailto = `mailto`
 )
 
 const (
@@ -93,161 +93,161 @@ const (
 )
 
 const (
-	attrNameAlign       = "align"
-	attrNameAlt         = "alt"
-	attrNameAttribution = "attribution"
-	attrNameCaption     = "caption"
-	attrNameCitation    = "citation"
-	attrNameCols        = "cols"
-	attrNameDiscrete    = "discrete"
-	attrNameEnd         = "end"
-	attrNameFloat       = "float"
-	attrNameFrame       = "frame"
-	attrNameGrid        = "grid"
-	attrNameHeight      = "height"
-	attrNameHref        = "href"
-	attrNameIcons       = "icons"
-	attrNameLang        = "lang"
-	attrNameLink        = "link"
-	attrNameOptions     = "options"
-	attrNameOpts        = "opts"
-	attrNamePoster      = "poster"
-	attrNameRefText     = "reftext"
-	attrNameRel         = "rel"
-	attrNameRole        = "role"
-	attrNameSource      = "source"
-	attrNameSrc         = "src"
-	attrNameStart       = "start"
-	attrNameStripes     = "stripes"
-	attrNameTarget      = "target"
-	attrNameTheme       = "theme"
-	attrNameTitle       = "title"
-	attrNameVimeo       = "vimeo"
-	attrNameWidth       = "width"
-	attrNameYoutube     = "youtube"
-	attrNameYoutubeLang = "hl"
+	attrNameAlign       = `align`
+	attrNameAlt         = `alt`
+	attrNameAttribution = `attribution`
+	attrNameCaption     = `caption`
+	attrNameCitation    = `citation`
+	attrNameCols        = `cols`
+	attrNameDiscrete    = `discrete`
+	attrNameEnd         = `end`
+	attrNameFloat       = `float`
+	attrNameFrame       = `frame`
+	attrNameGrid        = `grid`
+	attrNameHeight      = `height`
+	attrNameHref        = `href`
+	attrNameIcons       = `icons`
+	attrNameLang        = `lang`
+	attrNameLink        = `link`
+	attrNameOptions     = `options`
+	attrNameOpts        = `opts`
+	attrNamePoster      = `poster`
+	attrNameRefText     = `reftext`
+	attrNameRel         = `rel`
+	attrNameRole        = `role`
+	attrNameSource      = `source`
+	attrNameSrc         = `src`
+	attrNameStart       = `start`
+	attrNameStripes     = `stripes`
+	attrNameTarget      = `target`
+	attrNameTheme       = `theme`
+	attrNameTitle       = `title`
+	attrNameVimeo       = `vimeo`
+	attrNameWidth       = `width`
+	attrNameYoutube     = `youtube`
+	attrNameYoutubeLang = `hl`
 )
 
 const (
-	attrValueAll       = "all"
-	attrValueAuthor    = "author"
-	attrValueBare      = "bare"
-	attrValueBlank     = "_blank"
-	attrValueCols      = "cols"
-	attrValueContent   = "content"
-	attrValueEmail     = "email"
-	attrValueEven      = "even"
-	attrValueFont      = "font"
-	attrValueFooter    = "footer"
-	attrValueHeader    = "header"
-	attrValueHover     = "hover"
-	attrValueImage     = "image"
-	attrValueNoopener  = "noopener"
-	attrValueNoHeader  = "noheader"
-	attrValueNone      = "none"
-	attrValueOdd       = "odd"
-	attrValueRevDate   = "revdate"
-	attrValueRevNumber = "revnumber"
-	attrValueRows      = "rows"
-	attrValueSides     = "sides"
+	attrValueAll       = `all`
+	attrValueAuthor    = `author`
+	attrValueBare      = `bare`
+	attrValueBlank     = `_blank`
+	attrValueCols      = `cols`
+	attrValueContent   = `content`
+	attrValueEmail     = `email`
+	attrValueEven      = `even`
+	attrValueFont      = `font`
+	attrValueFooter    = `footer`
+	attrValueHeader    = `header`
+	attrValueHover     = `hover`
+	attrValueImage     = `image`
+	attrValueNoopener  = `noopener`
+	attrValueNoHeader  = `noheader`
+	attrValueNone      = `none`
+	attrValueOdd       = `odd`
+	attrValueRevDate   = `revdate`
+	attrValueRevNumber = `revnumber`
+	attrValueRows      = `rows`
+	attrValueSides     = `sides`
 	attrValueTitle     = attrNameTitle
-	attrValueTopbot    = "topbot"
+	attrValueTopbot    = `topbot`
 )
 
 const (
-	classNameArabic       = "arabic"
-	classNameChecklist    = "checklist"
-	classNameFitContent   = "fit-content"
-	classNameFrameAll     = "frame-all"
-	classNameFrameEnds    = "frame-ends"
-	classNameFrameNone    = "frame-none"
-	classNameFrameSides   = "frame-sides"
-	classNameGridAll      = "grid-all"
-	classNameGridCols     = "grid-cols"
-	classNameGridNone     = "grid-none"
-	classNameGridRows     = "grid-rows"
-	classNameLoweralpha   = "loweralpha"
-	classNameLowerroman   = "lowerroman"
-	classNameStretch      = "stretch"
-	classNameStripesAll   = "stripes-all"
-	classNameStripesEven  = "stripes-even"
-	classNameStripesHover = "stripes-hover"
-	classNameStripesOdd   = "stripes-odd"
-	classNameTableblock   = "tableblock"
-	classNameUpperalpha   = "upperalpha"
-	classNameUpperroman   = "upperroman"
+	classNameArabic       = `arabic`
+	classNameChecklist    = `checklist`
+	classNameFitContent   = `fit-content`
+	classNameFrameAll     = `frame-all`
+	classNameFrameEnds    = `frame-ends`
+	classNameFrameNone    = `frame-none`
+	classNameFrameSides   = `frame-sides`
+	classNameGridAll      = `grid-all`
+	classNameGridCols     = `grid-cols`
+	classNameGridNone     = `grid-none`
+	classNameGridRows     = `grid-rows`
+	classNameLoweralpha   = `loweralpha`
+	classNameLowerroman   = `lowerroman`
+	classNameStretch      = `stretch`
+	classNameStripesAll   = `stripes-all`
+	classNameStripesEven  = `stripes-even`
+	classNameStripesHover = `stripes-hover`
+	classNameStripesOdd   = `stripes-odd`
+	classNameTableblock   = `tableblock`
+	classNameUpperalpha   = `upperalpha`
+	classNameUpperroman   = `upperroman`
 )
 
 // List of document metadata.
 const (
-	MetaNameAuthor      = "author"       // May contain the first author full name only.
-	MetaNameAuthorNames = "author_names" // List of author full names, separated by comma.
-	MetaNameDescription = "description"
-	MetaNameGenerator   = "generator"
-	MetaNameKeywords    = "keywords"
+	MetaNameAuthor      = `author`       // May contain the first author full name only.
+	MetaNameAuthorNames = `author_names` // List of author full names, separated by comma.
+	MetaNameDescription = `description`
+	MetaNameGenerator   = `generator`
+	MetaNameKeywords    = `keywords`
 
-	metaNameAuthorInitials = "authorinitials"
-	metaNameDocTitle       = "doctitle"
+	metaNameAuthorInitials = `authorinitials`
+	metaNameDocTitle       = `doctitle`
 	metaNameEmail          = attrValueEmail
-	metaNameFirstName      = "firstname"
-	metaNameIDPrefix       = "idprefix"
-	metaNameIDSeparator    = "idseparator"
-	metaNameLastName       = "lastname"
-	metaNameMiddleName     = "middlename"
-	metaNameNoFooter       = "nofooter"
-	metaNameNoHeader       = "noheader"
-	metaNameNoHeaderFooter = "no-header-footer"
-	metaNameNoTitle        = "notitle"
-	metaNameRevDate        = "revdate"
-	metaNameRevNumber      = "revnumber"
-	metaNameRevRemark      = "revremark"
-	metaNameSectAnchors    = "sectanchors"
-	metaNameSectIDs        = "sectids"
-	metaNameSectLinks      = "sectlinks"
-	metaNameSectNumLevel   = "sectnumlevels"
-	metaNameSectNums       = "sectnums"
-	metaNameShowTitle      = "showtitle"
-	metaNameTOC            = "toc"
-	metaNameTOCLevels      = "toclevels"
-	metaNameTOCTitle       = "toc-title"
-	metaNameTableCaption   = "table-caption"
+	metaNameFirstName      = `firstname`
+	metaNameIDPrefix       = `idprefix`
+	metaNameIDSeparator    = `idseparator`
+	metaNameLastName       = `lastname`
+	metaNameMiddleName     = `middlename`
+	metaNameNoFooter       = `nofooter`
+	metaNameNoHeader       = `noheader`
+	metaNameNoHeaderFooter = `no-header-footer`
+	metaNameNoTitle        = `notitle`
+	metaNameRevDate        = `revdate`
+	metaNameRevNumber      = `revnumber`
+	metaNameRevRemark      = `revremark`
+	metaNameSectAnchors    = `sectanchors`
+	metaNameSectIDs        = `sectids`
+	metaNameSectLinks      = `sectlinks`
+	metaNameSectNumLevel   = `sectnumlevels`
+	metaNameSectNums       = `sectnums`
+	metaNameShowTitle      = `showtitle`
+	metaNameTOC            = `toc`
+	metaNameTOCLevels      = `toclevels`
+	metaNameTOCTitle       = `toc-title`
+	metaNameTableCaption   = `table-caption`
 	metaNameTitle          = attrNameTitle
-	metaNameTitleSeparator = "title-separator"
-	metaNameVersionLabel   = "version-label"
+	metaNameTitleSeparator = `title-separator`
+	metaNameVersionLabel   = `version-label`
 )
 
 // List of possible metadata value.
 const (
-	metaValueAuto     = "auto"
-	metaValueMacro    = "macro"
-	metaValuePreamble = "preamble"
-	metaValueLeft     = "left"
-	metaValueRight    = "right"
+	metaValueAuto     = `auto`
+	metaValueMacro    = `macro`
+	metaValuePreamble = `preamble`
+	metaValueLeft     = `left`
+	metaValueRight    = `right`
 )
 
 const (
-	optNameAutoplay               = "autoplay"
-	optNameAutowidth              = "autowidth"
-	optNameControls               = "controls"
-	optNameLoop                   = "loop"
-	optNameNocontrols             = "nocontrols"
-	optVideoFullscreen            = "fs"
-	optVideoModest                = "modest"
-	optVideoNofullscreen          = "nofullscreen"
-	optVideoPlaylist              = "playlist"
-	optVideoYoutubeModestbranding = "modestbranding"
+	optNameAutoplay               = `autoplay`
+	optNameAutowidth              = `autowidth`
+	optNameControls               = `controls`
+	optNameLoop                   = `loop`
+	optNameNocontrols             = `nocontrols`
+	optVideoFullscreen            = `fs`
+	optVideoModest                = `modest`
+	optVideoNofullscreen          = `nofullscreen`
+	optVideoPlaylist              = `playlist`
+	optVideoYoutubeModestbranding = `modestbranding`
 )
 
 const (
-	prefixInclude = "include::"
+	prefixInclude = `include::`
 )
 
 const (
-	admonitionCaution   = "CAUTION"
-	admonitionImportant = "IMPORTANT"
-	admonitionNote      = "NOTE"
-	admonitionTip       = "TIP"
-	admonitionWarning   = "WARNING"
+	admonitionCaution   = `CAUTION`
+	admonitionImportant = `IMPORTANT`
+	admonitionNote      = `NOTE`
+	admonitionTip       = `TIP`
+	admonitionWarning   = `WARNING`
 )
 
 const (
@@ -285,77 +285,77 @@ const (
 )
 
 const (
-	symbolQuoteDoubleBegin = "&#8220;"
-	symbolQuoteDoubleEnd   = "&#8221;"
-	symbolQuoteSingleBegin = "&#8216;"
-	symbolQuoteSingleEnd   = "&#8217;"
-	symbolChecked          = "&#10003;"
-	symbolUnchecked        = "&#10063;"
+	symbolQuoteDoubleBegin = `&#8220;`
+	symbolQuoteDoubleEnd   = `&#8221;`
+	symbolQuoteSingleBegin = `&#8216;`
+	symbolQuoteSingleEnd   = `&#8217;`
+	symbolChecked          = `&#10003;`
+	symbolUnchecked        = `&#10063;`
 )
 
 var adocStyles map[string]int64 = map[string]int64{
-	"colophon":          styleSectionColophon,
-	"abstract":          styleSectionAbstract,
-	"preface":           styleSectionPreface,
-	"dedication":        styleSectionDedication,
+	`colophon`:          styleSectionColophon,
+	`abstract`:          styleSectionAbstract,
+	`preface`:           styleSectionPreface,
+	`dedication`:        styleSectionDedication,
 	attrNameDiscrete:    styleSectionDiscrete,
-	"partintro":         styleSectionPartIntroduction,
-	"appendix":          styleSectionAppendix,
-	"glossary":          styleSectionGlossary,
-	"bibliography":      styleSectionBibliography,
-	"index":             styleSectionIndex,
-	".lead":             styleParagraphLead,
-	".normal":           styleParagraphNormal,
-	"arabic":            styleNumberingArabic,
-	"decimal":           styleNumberingDecimal,
-	"loweralpha":        styleNumberingLoweralpha,
-	"upperalpha":        styleNumberingUpperalpha,
-	"lowerroman":        styleNumberingLowerroman,
-	"upperroman":        styleNumberingUpperroman,
-	"lowergreek":        styleNumberingLowergreek,
-	"horizontal":        styleDescriptionHorizontal,
-	"qanda":             styleDescriptionQandA,
+	`partintro`:         styleSectionPartIntroduction,
+	`appendix`:          styleSectionAppendix,
+	`glossary`:          styleSectionGlossary,
+	`bibliography`:      styleSectionBibliography,
+	`index`:             styleSectionIndex,
+	`.lead`:             styleParagraphLead,
+	`.normal`:           styleParagraphNormal,
+	`arabic`:            styleNumberingArabic,
+	`decimal`:           styleNumberingDecimal,
+	`loweralpha`:        styleNumberingLoweralpha,
+	`upperalpha`:        styleNumberingUpperalpha,
+	`lowerroman`:        styleNumberingLowerroman,
+	`upperroman`:        styleNumberingUpperroman,
+	`lowergreek`:        styleNumberingLowergreek,
+	`horizontal`:        styleDescriptionHorizontal,
+	`qanda`:             styleDescriptionQandA,
 	admonitionCaution:   styleAdmonition,
 	admonitionImportant: styleAdmonition,
 	admonitionNote:      styleAdmonition,
 	admonitionTip:       styleAdmonition,
 	admonitionWarning:   styleAdmonition,
-	"listing":           styleBlockListing,
-	"quote":             styleQuote,
-	"source":            styleSource,
-	"verse":             styleVerse,
+	`listing`:           styleBlockListing,
+	`quote`:             styleQuote,
+	`source`:            styleSource,
+	`verse`:             styleVerse,
 }
 
 var _attrRef map[string]string = map[string]string{
-	"amp":            "&",
-	"apos":           htmlSymbolSingleQuote, // '
-	"asterisk":       "*",
-	"backslash":      `\`,
-	"backtick":       "`",
-	"blank":          "",
-	"brvbar":         htmlSymbolBrokenVerticalBar, // ¦
-	"caret":          "^",
-	"cpp":            "C++",
-	"deg":            htmlSymbolDegreeSign, // °
-	"empty":          "",
-	"endsb":          "]",
-	"gt":             ">",
-	"ldquo":          htmlSymbolLeftDoubleQuote,
-	"lsquo":          htmlSymbolLeftSingleQuote,
-	"lt":             "<",
-	"nbsp":           htmlSymbolNonBreakingSpace,
-	"plus":           htmlSymbolPlus,
-	"quot":           htmlSymbolDoubleQuote,
-	"rdquo":          htmlSymbolRightDoubleQuote,
-	"rsquo":          htmlSymbolRightSingleQuote,
-	"sp":             " ",
-	"startsb":        "[",
-	"tilde":          "~",
-	"two-colons":     "::",
-	"two-semicolons": ";;",
-	"vbar":           "|",
-	"wj":             htmlSymbolWordJoiner,
-	"zwsp":           htmlSymbolZeroWidthSpace,
+	`amp`:            `&`,
+	`apos`:           htmlSymbolSingleQuote, // '
+	`asterisk`:       `*`,
+	`backslash`:      `\`,
+	`backtick`:       "`",
+	`blank`:          ``,
+	`brvbar`:         htmlSymbolBrokenVerticalBar, // ¦
+	`caret`:          `^`,
+	`cpp`:            `C++`,
+	`deg`:            htmlSymbolDegreeSign, // °
+	`empty`:          ``,
+	`endsb`:          `]`,
+	`gt`:             `>`,
+	`ldquo`:          htmlSymbolLeftDoubleQuote,
+	`lsquo`:          htmlSymbolLeftSingleQuote,
+	`lt`:             `<`,
+	`nbsp`:           htmlSymbolNonBreakingSpace,
+	`plus`:           htmlSymbolPlus,
+	`quot`:           htmlSymbolDoubleQuote,
+	`rdquo`:          htmlSymbolRightDoubleQuote,
+	`rsquo`:          htmlSymbolRightSingleQuote,
+	`sp`:             ` `,
+	`startsb`:        `[`,
+	`tilde`:          `~`,
+	`two-colons`:     `::`,
+	`two-semicolons`: `;;`,
+	`vbar`:           `|`,
+	`wj`:             htmlSymbolWordJoiner,
+	`zwsp`:           htmlSymbolZeroWidthSpace,
 }
 
 func applySubstitutions(doc *Document, content []byte) []byte {
@@ -500,7 +500,7 @@ func isLineDescriptionItem(line []byte) bool {
 		x int
 	)
 
-	_, x = indexUnescape(line, []byte(":: "))
+	_, x = indexUnescape(line, []byte(`:: `))
 	if x > 0 {
 		return true
 	}
@@ -508,7 +508,7 @@ func isLineDescriptionItem(line []byte) bool {
 	if x > 0 {
 		return true
 	}
-	_, x = indexUnescape(line, []byte("::"))
+	_, x = indexUnescape(line, []byte(`::`))
 	return x > 0
 }
 
@@ -578,7 +578,7 @@ func parseAttribute(line []byte, strict bool) (key, value string, ok bool) {
 	)
 
 	if !(ascii.IsAlnum(line[1]) || line[1] == '_') {
-		return "", "", false
+		return ``, ``, false
 	}
 
 	sb.WriteByte(line[1])
@@ -593,11 +593,11 @@ func parseAttribute(line []byte, strict bool) (key, value string, ok bool) {
 			continue
 		}
 		if strict {
-			return "", "", false
+			return ``, ``, false
 		}
 	}
 	if x == len(line) {
-		return "", "", false
+		return ``, ``, false
 	}
 
 	valb = bytes.TrimSpace(line[x+1:])
@@ -634,8 +634,8 @@ func parseAttrRef(doc *Document, content []byte, x int) (newContent []byte, ok b
 
 		// Add prefix "mailto:" if the ref name start with email, so
 		// it can be parsed by caller as macro link.
-		if name == "email" || strings.HasPrefix(name, "email_") {
-			attrValue = "mailto:" + attrValue + "[" + attrValue + "]"
+		if name == `email` || strings.HasPrefix(name, `email_`) {
+			attrValue = `mailto:` + attrValue + `[` + attrValue + `]`
 		}
 	}
 
@@ -650,7 +650,7 @@ func parseAttrRef(doc *Document, content []byte, x int) (newContent []byte, ok b
 // It will return empty id and label if ID is not valid.
 func parseIDLabel(s []byte) (id, label []byte) {
 	var (
-		idLabel [][]byte = bytes.Split(s, []byte(","))
+		idLabel [][]byte = bytes.Split(s, []byte(`,`))
 	)
 
 	id = idLabel[0]
@@ -699,68 +699,68 @@ func whatKindOfLine(line []byte) (kind int, spaces, got []byte) {
 	if len(line) == 0 {
 		return lineKindEmpty, nil, line
 	}
-	if bytes.HasPrefix(line, []byte("////")) {
+	if bytes.HasPrefix(line, []byte(`////`)) {
 		// Check for comment block first, since we use HasPrefix to
 		// check for single line comment.
 		return lineKindBlockComment, spaces, line
 	}
-	if bytes.HasPrefix(line, []byte("//")) {
+	if bytes.HasPrefix(line, []byte(`//`)) {
 		// Use HasPrefix to allow single line comment without space,
 		// for example "//comment".
 		return lineKindComment, spaces, line
 	}
-	if bytes.Equal(line, []byte("'''")) ||
-		bytes.Equal(line, []byte("---")) ||
-		bytes.Equal(line, []byte("- - -")) ||
-		bytes.Equal(line, []byte("***")) ||
-		bytes.Equal(line, []byte("* * *")) {
+	if bytes.Equal(line, []byte(`'''`)) ||
+		bytes.Equal(line, []byte(`---`)) ||
+		bytes.Equal(line, []byte(`- - -`)) ||
+		bytes.Equal(line, []byte(`***`)) ||
+		bytes.Equal(line, []byte(`* * *`)) {
 		return lineKindHorizontalRule, spaces, line
 	}
-	if bytes.Equal(line, []byte("<<<")) {
+	if bytes.Equal(line, []byte(`<<<`)) {
 		return lineKindPageBreak, spaces, line
 	}
-	if bytes.Equal(line, []byte("--")) {
+	if bytes.Equal(line, []byte(`--`)) {
 		return elKindBlockOpen, spaces, line
 	}
-	if bytes.Equal(line, []byte("____")) {
+	if bytes.Equal(line, []byte(`____`)) {
 		return elKindBlockExcerpts, spaces, line
 	}
-	if bytes.Equal(line, []byte("....")) {
+	if bytes.Equal(line, []byte(`....`)) {
 		return elKindBlockLiteral, nil, line
 	}
-	if bytes.Equal(line, []byte("++++")) {
+	if bytes.Equal(line, []byte(`++++`)) {
 		return elKindBlockPassthrough, spaces, line
 	}
-	if bytes.Equal(line, []byte("****")) {
+	if bytes.Equal(line, []byte(`****`)) {
 		return elKindBlockSidebar, nil, line
 	}
-	if bytes.Equal(line, []byte("====")) {
+	if bytes.Equal(line, []byte(`====`)) {
 		return elKindBlockExample, spaces, line
 	}
 
-	if bytes.HasPrefix(line, []byte("|===")) {
+	if bytes.HasPrefix(line, []byte(`|===`)) {
 		return elKindTable, nil, line
 	}
 
-	if bytes.Equal(line, []byte("[listing]")) {
+	if bytes.Equal(line, []byte(`[listing]`)) {
 		return elKindBlockListingNamed, nil, line
 	}
-	if bytes.Equal(line, []byte("[literal]")) {
+	if bytes.Equal(line, []byte(`[literal]`)) {
 		return elKindBlockLiteralNamed, nil, line
 	}
-	if bytes.Equal(line, []byte("toc::[]")) {
+	if bytes.Equal(line, []byte(`toc::[]`)) {
 		return elKindMacroTOC, spaces, line
 	}
-	if bytes.HasPrefix(line, []byte("image::")) {
+	if bytes.HasPrefix(line, []byte(`image::`)) {
 		return elKindBlockImage, spaces, line
 	}
-	if bytes.HasPrefix(line, []byte("include::")) {
+	if bytes.HasPrefix(line, []byte(`include::`)) {
 		return lineKindInclude, nil, line
 	}
-	if bytes.HasPrefix(line, []byte("video::")) {
+	if bytes.HasPrefix(line, []byte(`video::`)) {
 		return elKindBlockVideo, nil, line
 	}
-	if bytes.HasPrefix(line, []byte("audio::")) {
+	if bytes.HasPrefix(line, []byte(`audio::`)) {
 		return elKindBlockAudio, nil, line
 	}
 	if isAdmonition(line) {
@@ -828,15 +828,15 @@ func whatKindOfLine(line []byte) (kind int, spaces, got []byte) {
 			subs [][]byte = bytes.Fields(line)
 		)
 
-		if bytes.Equal(subs[0], []byte("==")) {
+		if bytes.Equal(subs[0], []byte(`==`)) {
 			kind = elKindSectionL1
-		} else if bytes.Equal(subs[0], []byte("===")) {
+		} else if bytes.Equal(subs[0], []byte(`===`)) {
 			kind = elKindSectionL2
-		} else if bytes.Equal(subs[0], []byte("====")) {
+		} else if bytes.Equal(subs[0], []byte(`====`)) {
 			kind = elKindSectionL3
-		} else if bytes.Equal(subs[0], []byte("=====")) {
+		} else if bytes.Equal(subs[0], []byte(`=====`)) {
 			kind = elKindSectionL4
-		} else if bytes.Equal(subs[0], []byte("======")) {
+		} else if bytes.Equal(subs[0], []byte(`======`)) {
 			kind = elKindSectionL5
 		}
 	} else if line[0] == '.' {
@@ -873,9 +873,9 @@ func whatKindOfLine(line []byte) (kind int, spaces, got []byte) {
 				return kind, spaces, line
 			}
 		}
-	} else if bytes.Equal(line, []byte("+")) {
+	} else if bytes.Equal(line, []byte(`+`)) {
 		kind = lineKindListContinue
-	} else if bytes.Equal(line, []byte("----")) {
+	} else if bytes.Equal(line, []byte(`----`)) {
 		kind = elKindBlockListing
 	} else if isLineDescriptionItem(line) {
 		kind = elKindListDescriptionItem
diff --git a/parser_test.go b/parser_test.go
index d443530..ace7581 100644
--- a/parser_test.go
+++ b/parser_test.go
@@ -94,10 +94,10 @@ func TestIsValidID(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		id:  "a",
+		id:  `a`,
 		exp: true,
 	}, {
-		id: "1",
+		id: `1`,
 	}}
 
 	var (
diff --git a/revision_test.go b/revision_test.go
index 3e08e36..a5e5a23 100644
--- a/revision_test.go
+++ b/revision_test.go
@@ -16,44 +16,44 @@ func TestParseRevision(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		raw: "v1",
+		raw: `v1`,
 		exp: Revision{
-			Number: "1",
+			Number: `1`,
 		},
 	}, {
-		raw: "15 Nov, 2020",
+		raw: `15 Nov, 2020`,
 		exp: Revision{
-			Date: "15 Nov, 2020",
+			Date: `15 Nov, 2020`,
 		},
 	}, {
-		raw: ":remark",
+		raw: `:remark`,
 		exp: Revision{
-			Remark: "remark",
+			Remark: `remark`,
 		},
 	}, {
-		raw: "v1, 15 Nov, 2020",
+		raw: `v1, 15 Nov, 2020`,
 		exp: Revision{
-			Number: "1",
-			Date:   "15 Nov, 2020",
+			Number: `1`,
+			Date:   `15 Nov, 2020`,
 		},
 	}, {
-		raw: "v1: remark",
+		raw: `v1: remark`,
 		exp: Revision{
-			Number: "1",
-			Remark: "remark",
+			Number: `1`,
+			Remark: `remark`,
 		},
 	}, {
-		raw: "15 Nov, 2020: remark",
+		raw: `15 Nov, 2020: remark`,
 		exp: Revision{
-			Date:   "15 Nov, 2020",
-			Remark: "remark",
+			Date:   `15 Nov, 2020`,
+			Remark: `remark`,
 		},
 	}, {
-		raw: "v1, 15 Nov: remark",
+		raw: `v1, 15 Nov: remark`,
 		exp: Revision{
-			Number: "1",
-			Date:   "15 Nov",
-			Remark: "remark",
+			Number: `1`,
+			Date:   `15 Nov`,
+			Remark: `remark`,
 		},
 	}}
 
@@ -64,6 +64,6 @@ func TestParseRevision(t *testing.T) {
 
 	for _, c = range cases {
 		got = parseRevision(c.raw)
-		test.Assert(t, "Revision", c.exp, got)
+		test.Assert(t, `Revision`, c.exp, got)
 	}
 }
diff --git a/section_counters.go b/section_counters.go
index 7ca685b..8dff0e0 100644
--- a/section_counters.go
+++ b/section_counters.go
@@ -47,7 +47,7 @@ func (sec *sectionCounters) String() string {
 		if sec.nums[x] == 0 {
 			break
 		}
-		fmt.Fprintf(&sb, "%d.", sec.nums[x])
+		fmt.Fprintf(&sb, `%d.`, sec.nums[x])
 	}
 	sb.WriteByte(' ')
 	return sb.String()
diff --git a/section_counters_test.go b/section_counters_test.go
index 284b3d0..7018522 100644
--- a/section_counters_test.go
+++ b/section_counters_test.go
@@ -22,42 +22,42 @@ func TestSectionCounters(t *testing.T) {
 			nums: [6]byte{0, 1, 0, 0, 0, 0},
 			curr: 1,
 		},
-		expString: "1. ",
+		expString: `1. `,
 	}, {
 		level: 1,
 		exp: &sectionCounters{
 			nums: [6]byte{0, 2, 0, 0, 0, 0},
 			curr: 1,
 		},
-		expString: "2. ",
+		expString: `2. `,
 	}, {
 		level: 2,
 		exp: &sectionCounters{
 			nums: [6]byte{0, 2, 1, 0, 0, 0},
 			curr: 2,
 		},
-		expString: "2.1. ",
+		expString: `2.1. `,
 	}, {
 		level: 3,
 		exp: &sectionCounters{
 			nums: [6]byte{0, 2, 1, 1, 0, 0},
 			curr: 3,
 		},
-		expString: "2.1.1. ",
+		expString: `2.1.1. `,
 	}, {
 		level: 2,
 		exp: &sectionCounters{
 			nums: [6]byte{0, 2, 2, 0, 0, 0},
 			curr: 2,
 		},
-		expString: "2.2. ",
+		expString: `2.2. `,
 	}, {
 		level: 1,
 		exp: &sectionCounters{
 			nums: [6]byte{0, 3, 0, 0, 0, 0},
 			curr: 1,
 		},
-		expString: "3. ",
+		expString: `3. `,
 	}}
 
 	var (
@@ -71,7 +71,7 @@ func TestSectionCounters(t *testing.T) {
 	for _, c = range cases {
 		got = sec.set(c.level)
 		gotString = got.String()
-		test.Assert(t, "set", c.exp, got)
-		test.Assert(t, "String", c.expString, gotString)
+		test.Assert(t, `set`, c.exp, got)
+		test.Assert(t, `String`, c.expString, gotString)
 	}
 }
diff --git a/table_parser_test.go b/table_parser_test.go
index dd71f2e..0c37654 100644
--- a/table_parser_test.go
+++ b/table_parser_test.go
@@ -17,51 +17,51 @@ func TestTableParser_new(t *testing.T) {
 	}
 
 	var cases = []testCase{{
-		desc:    "empty content",
+		desc:    `empty content`,
 		content: ``,
 		exp:     nil,
 	}, {
-		desc:    "first cell without |",
-		content: "A1|B1",
+		desc:    `first cell without |`,
+		content: `A1|B1`,
 		exp: []*tableCell{{
-			content: []byte("A1"),
+			content: []byte(`A1`),
 		}, {
-			content: []byte("B1"),
+			content: []byte(`B1`),
 		}},
 	}, {
-		desc:    "first cell without |",
+		desc:    `first cell without |`,
 		content: "A1\nb|B1",
 		exp: []*tableCell{{
 			content: []byte("A1\nb"),
 		}, {
-			content: []byte("B1"),
+			content: []byte(`B1`),
 		}},
 	}, {
-		desc:    "single row",
+		desc:    `single row`,
 		content: `|A1|B1`,
 		exp: []*tableCell{{
-			content: []byte("A1"),
+			content: []byte(`A1`),
 		}, {
-			content: []byte("B1"),
+			content: []byte(`B1`),
 		}},
 	}, {
-		desc:    "two rows, empty header",
+		desc:    `two rows, empty header`,
 		content: "\n|A1",
 		exp: []*tableCell{nil, {
-			content: []byte("A1"),
+			content: []byte(`A1`),
 		}},
 	}, {
-		desc:    "three rows, empty header",
+		desc:    `three rows, empty header`,
 		content: "\n|A1 |\n\nb\n\n|A2",
 		exp: []*tableCell{nil, {
-			content: []byte("A1 "),
+			content: []byte(`A1 `),
 		}, {
 			content: []byte("\n\nb"),
 		}, nil, {
-			content: []byte("A2"),
+			content: []byte(`A2`),
 		}},
 	}, {
-		desc:    "with cell formatting",
+		desc:    `with cell formatting`,
 		content: "3*|DUP\n^|A2\n3*x|B2\n>|C2",
 		exp: []*tableCell{{
 			content: []byte("DUP\n"),
@@ -76,7 +76,7 @@ func TestTableParser_new(t *testing.T) {
 		}, {
 			content: []byte("B2\n"),
 		}, {
-			content: []byte("C2"),
+			content: []byte(`C2`),
 			format: cellFormat{
 				alignHor: colAlignBottom,
 			},