1package extension
2
3import (
4 "regexp"
5
6 "github.com/yuin/goldmark"
7 gast "github.com/yuin/goldmark/ast"
8 "github.com/yuin/goldmark/extension/ast"
9 "github.com/yuin/goldmark/parser"
10 "github.com/yuin/goldmark/renderer"
11 "github.com/yuin/goldmark/renderer/html"
12 "github.com/yuin/goldmark/text"
13 "github.com/yuin/goldmark/util"
14)
15
16var taskListRegexp = regexp.MustCompile(`^\[([\sxX])\]\s*`)
17
18type taskCheckBoxParser struct {
19}
20
21var defaultTaskCheckBoxParser = &taskCheckBoxParser{}
22
23// NewTaskCheckBoxParser returns a new InlineParser that can parse
24// checkboxes in list items.
25// This parser must take precedence over the parser.LinkParser.
26func NewTaskCheckBoxParser() parser.InlineParser {
27 return defaultTaskCheckBoxParser
28}
29
30func (s *taskCheckBoxParser) Trigger() []byte {
31 return []byte{'['}
32}
33
34func (s *taskCheckBoxParser) Parse(parent gast.Node, block text.Reader, pc parser.Context) gast.Node {
35 // Given AST structure must be like
36 // - List
37 // - ListItem : parent.Parent
38 // - TextBlock : parent
39 // (current line)
40 if parent.Parent() == nil || parent.Parent().FirstChild() != parent {
41 return nil
42 }
43
44 if parent.HasChildren() {
45 return nil
46 }
47 if _, ok := parent.Parent().(*gast.ListItem); !ok {
48 return nil
49 }
50 line, _ := block.PeekLine()
51 m := taskListRegexp.FindSubmatchIndex(line)
52 if m == nil {
53 return nil
54 }
55 value := line[m[2]:m[3]][0]
56 block.Advance(m[1])
57 checked := value == 'x' || value == 'X'
58 return ast.NewTaskCheckBox(checked)
59}
60
61func (s *taskCheckBoxParser) CloseBlock(parent gast.Node, pc parser.Context) {
62 // nothing to do
63}
64
65// TaskCheckBoxHTMLRenderer is a renderer.NodeRenderer implementation that
66// renders checkboxes in list items.
67type TaskCheckBoxHTMLRenderer struct {
68 html.Config
69}
70
71// NewTaskCheckBoxHTMLRenderer returns a new TaskCheckBoxHTMLRenderer.
72func NewTaskCheckBoxHTMLRenderer(opts ...html.Option) renderer.NodeRenderer {
73 r := &TaskCheckBoxHTMLRenderer{
74 Config: html.NewConfig(),
75 }
76 for _, opt := range opts {
77 opt.SetHTMLOption(&r.Config)
78 }
79 return r
80}
81
82// RegisterFuncs implements renderer.NodeRenderer.RegisterFuncs.
83func (r *TaskCheckBoxHTMLRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
84 reg.Register(ast.KindTaskCheckBox, r.renderTaskCheckBox)
85}
86
87func (r *TaskCheckBoxHTMLRenderer) renderTaskCheckBox(
88 w util.BufWriter, source []byte, node gast.Node, entering bool) (gast.WalkStatus, error) {
89 if !entering {
90 return gast.WalkContinue, nil
91 }
92 n := node.(*ast.TaskCheckBox)
93
94 if n.IsChecked {
95 _, _ = w.WriteString(`<input checked="" disabled="" type="checkbox"`)
96 } else {
97 _, _ = w.WriteString(`<input disabled="" type="checkbox"`)
98 }
99 if r.XHTML {
100 _, _ = w.WriteString(" /> ")
101 } else {
102 _, _ = w.WriteString("> ")
103 }
104 return gast.WalkContinue, nil
105}
106
107type taskList struct {
108}
109
110// TaskList is an extension that allow you to use GFM task lists.
111var TaskList = &taskList{}
112
113func (e *taskList) Extend(m goldmark.Markdown) {
114 m.Parser().AddOptions(parser.WithInlineParsers(
115 util.Prioritized(NewTaskCheckBoxParser(), 0),
116 ))
117 m.Renderer().AddOptions(renderer.WithNodeRenderers(
118 util.Prioritized(NewTaskCheckBoxHTMLRenderer(), 500),
119 ))
120}