Use markdown frontmatter to provide Table of contents, language and frontmatter rendering (#11047)

* Add control for the rendering of the frontmatter
* Add control to include a TOC
* Add control to set language - allows control of ToC header and CJK glyph choice.

Signed-off-by: Andrew Thornton art27@cantab.net

modules/markup/markdown/ast.go

@@ -0,0 +1,107 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package markdown
+
+import "github.com/yuin/goldmark/ast"
+
+// Details is a block that contains Summary and details
+type Details struct {
+	ast.BaseBlock
+}
+
+// Dump implements Node.Dump .
+func (n *Details) Dump(source []byte, level int) {
+	ast.DumpHelper(n, source, level, nil, nil)
+}
+
+// KindDetails is the NodeKind for Details
+var KindDetails = ast.NewNodeKind("Details")
+
+// Kind implements Node.Kind.
+func (n *Details) Kind() ast.NodeKind {
+	return KindDetails
+}
+
+// NewDetails returns a new Paragraph node.
+func NewDetails() *Details {
+	return &Details{
+		BaseBlock: ast.BaseBlock{},
+	}
+}
+
+// IsDetails returns true if the given node implements the Details interface,
+// otherwise false.
+func IsDetails(node ast.Node) bool {
+	_, ok := node.(*Details)
+	return ok
+}
+
+// Summary is a block that contains the summary of details block
+type Summary struct {
+	ast.BaseBlock
+}
+
+// Dump implements Node.Dump .
+func (n *Summary) Dump(source []byte, level int) {
+	ast.DumpHelper(n, source, level, nil, nil)
+}
+
+// KindSummary is the NodeKind for Summary
+var KindSummary = ast.NewNodeKind("Summary")
+
+// Kind implements Node.Kind.
+func (n *Summary) Kind() ast.NodeKind {
+	return KindSummary
+}
+
+// NewSummary returns a new Summary node.
+func NewSummary() *Summary {
+	return &Summary{
+		BaseBlock: ast.BaseBlock{},
+	}
+}
+
+// IsSummary returns true if the given node implements the Summary interface,
+// otherwise false.
+func IsSummary(node ast.Node) bool {
+	_, ok := node.(*Summary)
+	return ok
+}
+
+// Icon is an inline for a fomantic icon
+type Icon struct {
+	ast.BaseInline
+	Name []byte
+}
+
+// Dump implements Node.Dump .
+func (n *Icon) Dump(source []byte, level int) {
+	m := map[string]string{}
+	m["Name"] = string(n.Name)
+	ast.DumpHelper(n, source, level, m, nil)
+}
+
+// KindIcon is the NodeKind for Icon
+var KindIcon = ast.NewNodeKind("Icon")
+
+// Kind implements Node.Kind.
+func (n *Icon) Kind() ast.NodeKind {
+	return KindIcon
+}
+
+// NewIcon returns a new Paragraph node.
+func NewIcon(name string) *Icon {
+	return &Icon{
+		BaseInline: ast.BaseInline{},
+		Name:       []byte(name),
+	}
+}
+
+// IsIcon returns true if the given node implements the Icon interface,
+// otherwise false.
+func IsIcon(node ast.Node) bool {
+	_, ok := node.(*Icon)
+	return ok
+}