bug(parser): failure to convert nested elements (#740)

Fixes #739

pkg/parser/document_processing_apply_substitutions.go

@@ -499,17 +499,33 @@ func normalParagraph(_ ...Option) paragraphSubstitution {
 	}
 }
 
-func serializeParagraph(lines []interface{}) (io.Reader, error) {
-	buf := strings.Builder{}
-	for i, line := range lines {
-		if r, ok := line.(types.RawLine); ok {
-			buf.WriteString(r.Content)
-			if i < len(lines)-1 {
-				buf.WriteString("\n")
+func serializeRawLines(w *strings.Builder, line interface{}) error {
+	if line == nil {
+		return nil
+	}
+	switch line := line.(type) {
+	case types.RawLine:
+		if w.Len() > 0 {
+			w.WriteString("\n")
+		}
+		w.WriteString(line.Content)
+	case []interface{}:
+		for _, line := range line {
+			if err := serializeRawLines(w, line); err != nil {
+				return err
 			}
-		} else {
-			return nil, fmt.Errorf("unexpected type of element while serializing a paragraph: '%T'", line)
 		}
+	default:
+		return fmt.Errorf("unexpected element type serializing raw lines: '%T'", line)
+	}
+	return nil
+}
+
+func serializeParagraph(lines []interface{}) (io.Reader, error) {
+	buf := &strings.Builder{}
+	err := serializeRawLines(buf, lines)
+	if err != nil {
+		return nil, err
 	}
 	return strings.NewReader(buf.String()), nil
 }

pkg/parser/paragraph_test.go

@@ -856,5 +856,91 @@ a foo image:foo.png[]`
 				Expect(ParseDocument(source)).To(MatchDocument(expected))
 			})
 		})
+
+		Context("list paragraphs", func() {
+
+			It("inline image within a quote", func() {
+				source := `item::
+This is the first line of the first paragraph.
+This is the second line of the first paragraph.
++
+This is the first line of the continuation paragraph.
+This is the second line of the continuation paragraph.
++
+This is the next continuation paragraph.
++
+TIP: We can embed admonitions too!
+`
+				expected := types.Document{
+					Elements: []interface{}{
+						types.LabeledList{
+							Items: []types.LabeledListItem{
+								{
+									Level: 1,
+									Term: []interface{}{
+										types.StringElement{
+											Content: "item",
+										},
+									},
+									Elements: []interface{}{
+										types.Paragraph{
+											Lines: []interface{}{
+												[]interface{}{
+													types.StringElement{
+														Content: "This is the first line of the first paragraph.",
+													},
+												},
+												[]interface{}{
+													types.StringElement{
+														Content: "This is the second line of the first paragraph.",
+													},
+												},
+											},
+										},
+										types.Paragraph{
+											Lines: []interface{}{
+												[]interface{}{
+													types.StringElement{
+														Content: "This is the first line of the continuation paragraph.",
+													},
+												},
+												[]interface{}{
+													types.StringElement{
+														Content: "This is the second line of the continuation paragraph.",
+													},
+												},
+											},
+										},
+										types.Paragraph{
+											Lines: []interface{}{
+												[]interface{}{
+													types.StringElement{
+														Content: "This is the next continuation paragraph.",
+													},
+												},
+											},
+										},
+										types.Paragraph{
+											Attributes: types.Attributes{
+												types.AttrAdmonitionKind: types.Tip,
+											},
+											Lines: []interface{}{
+												[]interface{}{
+													types.StringElement{
+														Content: "We can embed admonitions too!",
+													},
+												},
+											},
+										},
+									},
+								},
+							},
+						},
+					},
+				}
+				Expect(ParseDocument(source)).To(MatchDocument(expected))
+			})
+		})
+
 	})
 })