Define EastAsianLineBreaksStyle to specify behavior of line breaking

extension/cjk.go

@@ -9,31 +9,31 @@ import (
 // A CJKOption sets options for CJK support mostly for HTML based renderers.
 type CJKOption func(*cjk)
 
-// A EastAsianLineBreaksOption sets options for east asian line breaks.
+// A EastAsianLineBreaksStyle is a style of east asian line breaks.
-type EastAsianLineBreaksOption func(*eastAsianLineBreaks)
+type EastAsianLineBreaksStyle int
+
+const (
+	EastAsianLineBreaksStyleSimple EastAsianLineBreaksStyle = iota
+	EastAsianLineBreaksCSS3Draft
+)
+
+type EastAsianLineBreaksFunction func()
 
 // WithEastAsianLineBreaks is a functional option that indicates whether softline breaks
 // between east asian wide characters should be ignored.
-func WithEastAsianLineBreaks(opts ...EastAsianLineBreaksOption) CJKOption {
+func WithEastAsianLineBreaks(style ...EastAsianLineBreaksStyle) CJKOption {
 	return func(c *cjk) {
 		e := &eastAsianLineBreaks{
 			Enabled:                  true,
+			EastAsianLineBreaksStyle: EastAsianLineBreaksStyleSimple,
 		}
-		for _, opt := range opts {
+		for _, s := range style {
-			opt(e)
+			e.EastAsianLineBreaksStyle = s
 		}
 		c.EastAsianLineBreaks = e
 	}
 }
 
-// WithWorksEvenWithOneSide is a functional option that indicates that a softline break
-// is ignored even if only one side of the break is east asian wide character.
-func WithWorksEvenWithOneSide() EastAsianLineBreaksOption {
-	return func(e *eastAsianLineBreaks) {
-		e.WorksEvenWithOneSide = true
-	}
-}
-
 // WithEscapedSpace is a functional option that indicates that a '\' escaped half-space(0x20) should not be rendered.
 func WithEscapedSpace() CJKOption {
 	return func(c *cjk) {
@@ -48,7 +48,7 @@ type cjk struct {
 
 type eastAsianLineBreaks struct {
 	Enabled                  bool
-	WorksEvenWithOneSide bool
+	EastAsianLineBreaksStyle EastAsianLineBreaksStyle
 }
 
 // CJK is a goldmark extension that provides functionalities for CJK languages.
@@ -66,13 +66,13 @@ func NewCJK(opts ...CJKOption) goldmark.Extender {
 func (e *cjk) Extend(m goldmark.Markdown) {
 	if e.EastAsianLineBreaks != nil {
 		if e.EastAsianLineBreaks.Enabled {
-			opts := []html.EastAsianLineBreaksOption{}
+			style := html.EastAsianLineBreaksStyleSimple
-			if e.EastAsianLineBreaks.WorksEvenWithOneSide {
+			switch e.EastAsianLineBreaks.EastAsianLineBreaksStyle {
-				opts = append(opts, html.WithWorksEvenWithOneSide())
+			case EastAsianLineBreaksCSS3Draft:
+				style = html.EastAsianLineBreaksCSS3Draft
 			}
-			m.Renderer().AddOptions(html.WithEastAsianLineBreaks(opts...))
+			m.Renderer().AddOptions(html.WithEastAsianLineBreaks(style))
 		}
-
 	}
 	if e.EscapedSpace {
 		m.Renderer().AddOptions(html.WithWriter(html.NewWriter(html.WithEscapedSpace())))

extension/cjk_test.go

@@ -209,13 +209,13 @@ func TestEastAsianLineBreaks(t *testing.T) {
 		t,
 	)
 
-	// WithWorksEvenWithOneSide option
+	// test with EastAsianLineBreaksCSS3Draft
 	markdown = goldmark.New(goldmark.WithRendererOptions(
 		html.WithXHTML(),
 		html.WithUnsafe(),
 	),
 		goldmark.WithExtensions(
-			NewCJK(WithEastAsianLineBreaks(WithWorksEvenWithOneSide())),
+			NewCJK(WithEastAsianLineBreaks(EastAsianLineBreaksCSS3Draft)),
 		),
 	)
 	no = 9

renderer/html/html.go

@@ -103,52 +103,75 @@ func WithHardWraps() interface {
 // EastAsianLineBreaks is an option name used in WithEastAsianLineBreaks.
 const optEastAsianLineBreaks renderer.OptionName = "EastAsianLineBreaks"
 
+type EastAsianLineBreaksStyle int
+
+const (
+	EastAsianLineBreaksStyleSimple EastAsianLineBreaksStyle = iota
+	EastAsianLineBreaksCSS3Draft
+)
+
+type eastAsianLineBreaksFunction interface {
+	SoftLineBreak(thisLastRune rune, siblingFirstRune rune) bool
+}
+
+type eastAsianLineBreaksSimple struct{}
+
+func (e *eastAsianLineBreaksSimple) SoftLineBreak(thisLastRune rune, siblingFirstRune rune) bool {
+	return !(util.IsEastAsianWideRune(thisLastRune) && util.IsEastAsianWideRune(siblingFirstRune))
+}
+
+type eastAsianLineBreaksCSS3Draft struct{}
+
+func (e *eastAsianLineBreaksCSS3Draft) SoftLineBreak(thisLastRune rune, siblingFirstRune rune) bool {
+	return !(util.IsEastAsianWideRune(thisLastRune) || util.IsEastAsianWideRune(siblingFirstRune))
+}
+
 type eastAsianLineBreaks struct {
 	Enabled                     bool
-	WorksEvenWithOneSide bool
+	EastAsianLineBreaksFunction eastAsianLineBreaksFunction
 }
 
 type withEastAsianLineBreaks struct {
-	worksEvenWithOneSide bool
+	eastAsianLineBreaksStyle EastAsianLineBreaksStyle
 }
 
-// A EastAsianLineBreaksOption sets options for east asian line breaks.
-type EastAsianLineBreaksOption func(*withEastAsianLineBreaks)
-
 func (o *withEastAsianLineBreaks) SetConfig(c *renderer.Config) {
+	switch o.eastAsianLineBreaksStyle {
+	case EastAsianLineBreaksStyleSimple:
 		c.Options[optEastAsianLineBreaks] = eastAsianLineBreaks{
 			Enabled:                     true,
-		WorksEvenWithOneSide: o.worksEvenWithOneSide,
+			EastAsianLineBreaksFunction: &eastAsianLineBreaksSimple{},
+		}
+	case EastAsianLineBreaksCSS3Draft:
+		c.Options[optEastAsianLineBreaks] = eastAsianLineBreaks{
+			Enabled:                     true,
+			EastAsianLineBreaksFunction: &eastAsianLineBreaksCSS3Draft{},
+		}
 	}
 }
 
 func (o *withEastAsianLineBreaks) SetHTMLOption(c *Config) {
+	switch o.eastAsianLineBreaksStyle {
+	case EastAsianLineBreaksStyleSimple:
 		c.EastAsianLineBreaks = eastAsianLineBreaks{
 			Enabled:                     true,
-		WorksEvenWithOneSide: o.worksEvenWithOneSide,
+			EastAsianLineBreaksFunction: &eastAsianLineBreaksSimple{},
+		}
+	case EastAsianLineBreaksCSS3Draft:
+		c.EastAsianLineBreaks = eastAsianLineBreaks{
+			Enabled:                     true,
+			EastAsianLineBreaksFunction: &eastAsianLineBreaksCSS3Draft{},
+		}
 	}
 }
 
 // WithEastAsianLineBreaks is a functional option that indicates whether softline breaks
 // between east asian wide characters should be ignored.
-func WithEastAsianLineBreaks(opts ...EastAsianLineBreaksOption) interface {
+func WithEastAsianLineBreaks(style EastAsianLineBreaksStyle) interface {
 	renderer.Option
 	Option
 } {
-	w := &withEastAsianLineBreaks{}
+	return &withEastAsianLineBreaks{style}
-	for _, opt := range opts {
-		opt(w)
-	}
-
-	return w
-}
-
-// WithWorksEvenWithOneSide is a functional option that indicates that a softline break
-// is ignored even if only one side of the break is east asian wide character.
-func WithWorksEvenWithOneSide() EastAsianLineBreaksOption {
-	return func(o *withEastAsianLineBreaks) {
-		o.worksEvenWithOneSide = true
-	}
 }
 
 // XHTML is an option name used in WithXHTML.
@@ -697,17 +720,9 @@ func (r *Renderer) renderText(w util.BufWriter, source []byte, node ast.Node, en
 					if siblingText := sibling.(*ast.Text).Text(source); len(siblingText) != 0 {
 						thisLastRune := util.ToRune(value, len(value)-1)
 						siblingFirstRune, _ := utf8.DecodeRune(siblingText)
-						if r.EastAsianLineBreaks.WorksEvenWithOneSide {
+						if r.EastAsianLineBreaks.EastAsianLineBreaksFunction.SoftLineBreak(thisLastRune, siblingFirstRune) {
-							if !(util.IsEastAsianWideRune(thisLastRune) ||
-								util.IsEastAsianWideRune(siblingFirstRune)) {
 							_ = w.WriteByte('\n')
 						}
-						} else {
-							if !(util.IsEastAsianWideRune(thisLastRune) &&
-								util.IsEastAsianWideRune(siblingFirstRune)) {
-								_ = w.WriteByte('\n')
-							}
-						}
 					}
 				}
 			} else {