feat: support MyST

Closes #667.

Signed-off-by: Joseph Kato <joseph@jdkato.io>

Author: jdkato

internal/core/format.go

@@ -74,6 +74,7 @@ var FormatByExtension = map[string][]string{
 	`\.(?:lua)$`:                             {".lua", "code"},
 	`\.(?:md|mdown|markdown|markdn|[Rr]md)$`: {".md", "markup"},
 	`\.(?:mdx)$`:                             {".mdx", "markup"},
+	`\.(?:myst)$`:                            {".myst", "markup"},
 	`\.(?:org)$`:                             {".org", "markup"},
 	`\.(?:php)$`:                             {".php", "code"},
 	`\.(?:pl|pm|pod)$`:                       {".r", "code"},

internal/lint/ast.go

@@ -23,6 +23,11 @@ var inlineTags = []string{
 	"b", "big", "i", "small", "abbr", "acronym", "cite", "dfn", "em", "kbd",
 	"strong", "a", "br", "img", "span", "sub", "sup", "code", "tt", "del"}
 
+// voidTags never carry content, so they are never "open" as containers.
+var voidTags = []string{
+	"area", "base", "br", "col", "embed", "hr", "img", "input", "link",
+	"meta", "source", "track", "wbr"}
+
 // inlineToScope names the inline elements that can be scoped on their own.
 //
 // These are siblings of `text`, not children of it: a scope of `text` is
@@ -92,6 +97,13 @@ func (l *Linter) lintHTMLTokens(f *core.File, raw []byte, offset int) error { //
 		class = getAttribute(tok, "class")
 		skipClass = checkClasses(class, skipClasses)
 
+		if tokt == html.StartTagToken && !core.StringInSlice(txt, inlineTags) &&
+			!core.StringInSlice(txt, voidTags) {
+			walker.enclose(txt, class)
+		} else if tokt == html.EndTagToken && !core.StringInSlice(txt, inlineTags) {
+			walker.unclose(txt)
+		}
+
 		blockSkip := skipClass && !core.StringInSlice(txt, inlineTags)
 		if tokt == html.ErrorToken { //nolint:gocritic
 			break

internal/lint/html.go

@@ -32,6 +32,7 @@ var blockDelimiters = map[string]string{
 	".adoc": "\n----\n$1\n----\n",
 	".md":   "\n```\n$1\n```\n",
 	".mdx":  "\n```\n$1\n```\n",
+	".myst": "\n```\n$1\n```\n",
 	".rst":  "\n::\n\n%s\n",
 	".org":  orgExample,
 }
@@ -84,6 +85,7 @@ var inlineDelimiters = map[string]string{
 	".adoc": "`$1`",
 	".md":   "`$1`",
 	".mdx":  "`$1`",
+	".myst": "`$1`",
 	".rst":  "``$1``",
 	".org":  "=$1=",
 }

internal/lint/lint.go

@@ -246,6 +246,8 @@ func (l *Linter) lintFile(src string) lintResult {
 			err = l.lintMarkdown(file)
 		case ".mdx":
 			err = l.lintMDX(file)
+		case ".myst":
+			err = l.lintMyST(file)
 		case ".rst":
 			err = l.lintRST(file)
 		case ".xml", ".xsd":

internal/lint/md.go

@@ -37,6 +37,12 @@ var reLinkDef = regexp.MustCompile(`\[(?:[^]\n]+)\]:`)
 var reNumericList = regexp.MustCompile(`(?m)^\d+\.`)
 
 func (l *Linter) lintMarkdown(f *core.File) error {
+	return l.lintMarkdownWith(f, goldMd)
+}
+
+// lintMarkdownWith lints f as Markdown read by the given converter -- the
+// plain configuration, or a dialect's such as MyST's.
+func (l *Linter) lintMarkdownWith(f *core.File, md goldmark.Markdown) error {
 	var buf bytes.Buffer
 
 	err := l.lintMetadata(f)
@@ -49,7 +55,7 @@ func (l *Linter) lintMarkdown(f *core.File) error {
 		return err
 	}
 
-	if err = goldMd.Convert([]byte(s), &buf); err != nil {
+	if err = md.Convert([]byte(s), &buf); err != nil {
 		return core.NewE100(f.Path, err)
 	}