Use a Renderer interface instead of rendering fragments

codeblock.go

@@ -0,0 +1,32 @@
+package gold
+
+import (
+	"io"
+
+	"github.com/alecthomas/chroma/quick"
+	bf "gopkg.in/russross/blackfriday.v2"
+)
+
+type CodeBlockElement struct {
+	Code     string
+	Language string
+}
+
+func (e *CodeBlockElement) Render(w io.Writer, node *bf.Node, tr *TermRenderer) error {
+	var theme string
+	rules := tr.style[CodeBlock]
+	if rules != nil {
+		theme = rules.Theme
+	}
+
+	if len(theme) > 0 {
+		return quick.Highlight(w, e.Code, e.Language, "terminal16m", theme)
+	}
+
+	// fallback rendering
+	el := &BaseElement{
+		Token: string(node.Literal),
+		Style: CodeBlock,
+	}
+	return el.Render(w, node, tr)
+}