1 files changed, 39 insertions, 0 deletions
diff --git a/markdown/ast_header.go b/markdown/ast_header.go
new file mode 100644
index 0000000..d51b046
--- /dev/null
+++ b/markdown/ast_header.go
@@ -0,0 +1,39 @@
+package markdown
+
+import (
+	"errors"
+	"fmt"
+	"html/template"
+)
+
+var ErrInvalidHeader = errors.New("invalid header")
+
+type astHeader struct {
+	level   uint
+	content *astParagraph
+}
+
+func (a *astHeader) Eval() (template.HTML, *ParseError) {
+	if a.level > 6 {
+		return "", &ParseError{lxs: lexers{}, internal: ErrInvalidCodeFormat}
+	}
+	var content template.HTML
+	content, err := a.content.Eval()
+	if err != nil {
+		return "", err
+	}
+	return template.HTML(fmt.Sprintf("<h%d>%s</h%d>", a.level, trimSpace(content), a.level)), nil
+}
+
+func header(lxs *lexers) (*astHeader, *ParseError) {
+	b := &astHeader{level: uint(len(lxs.Current().Value))}
+	if !lxs.Next() {
+		return nil, &ParseError{lxs: *lxs, internal: ErrInvalidHeader}
+	}
+	var err *ParseError
+	b.content, err = paragraph(lxs, true)
+	if err != nil {
+		return nil, err
+	}
+	return b, nil
+}