cjk.go

Documentation: github.com/yuin/goldmark/extension

     1  package extension
     2  
     3  import (
     4  	"github.com/yuin/goldmark"
     5  	"github.com/yuin/goldmark/parser"
     6  	"github.com/yuin/goldmark/renderer/html"
     7  )
     8  
     9  // A CJKOption sets options for CJK support mostly for HTML based renderers.
    10  type CJKOption func(*cjk)
    11  
    12  // A EastAsianLineBreaks is a style of east asian line breaks.
    13  type EastAsianLineBreaks int
    14  
    15  const (
    16  	//EastAsianLineBreaksNone renders line breaks as it is.
    17  	EastAsianLineBreaksNone EastAsianLineBreaks = iota
    18  	// EastAsianLineBreaksSimple is a style where soft line breaks are ignored
    19  	// if both sides of the break are east asian wide characters.
    20  	EastAsianLineBreaksSimple
    21  	// EastAsianLineBreaksCSS3Draft is a style where soft line breaks are ignored
    22  	// even if only one side of the break is an east asian wide character.
    23  	EastAsianLineBreaksCSS3Draft
    24  )
    25  
    26  // WithEastAsianLineBreaks is a functional option that indicates whether softline breaks
    27  // between east asian wide characters should be ignored.
    28  // style defauts to [EastAsianLineBreaksSimple] .
    29  func WithEastAsianLineBreaks(style ...EastAsianLineBreaks) CJKOption {
    30  	return func(c *cjk) {
    31  		if len(style) == 0 {
    32  			c.EastAsianLineBreaks = EastAsianLineBreaksSimple
    33  			return
    34  		}
    35  		c.EastAsianLineBreaks = style[0]
    36  	}
    37  }
    38  
    39  // WithEscapedSpace is a functional option that indicates that a '\' escaped half-space(0x20) should not be rendered.
    40  func WithEscapedSpace() CJKOption {
    41  	return func(c *cjk) {
    42  		c.EscapedSpace = true
    43  	}
    44  }
    45  
    46  type cjk struct {
    47  	EastAsianLineBreaks EastAsianLineBreaks
    48  	EscapedSpace        bool
    49  }
    50  
    51  // CJK is a goldmark extension that provides functionalities for CJK languages.
    52  var CJK = NewCJK(WithEastAsianLineBreaks(), WithEscapedSpace())
    53  
    54  // NewCJK returns a new extension with given options.
    55  func NewCJK(opts ...CJKOption) goldmark.Extender {
    56  	e := &cjk{
    57  		EastAsianLineBreaks: EastAsianLineBreaksNone,
    58  	}
    59  	for _, opt := range opts {
    60  		opt(e)
    61  	}
    62  	return e
    63  }
    64  
    65  func (e *cjk) Extend(m goldmark.Markdown) {
    66  	m.Renderer().AddOptions(html.WithEastAsianLineBreaks(
    67  		html.EastAsianLineBreaks(e.EastAsianLineBreaks)))
    68  	if e.EscapedSpace {
    69  		m.Renderer().AddOptions(html.WithWriter(html.NewWriter(html.WithEscapedSpace())))
    70  		m.Parser().AddOptions(parser.WithEscapedSpace())
    71  	}
    72  }
    73
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