Add minimal affiliated keyword support. Just captions for now

org/keyword.go

@@ -10,10 +10,16 @@ type Keyword struct {
 	Value string
 }
 
+type NodeWithMeta struct {
+	Node Node
+	Meta map[string]string
+}
+
 type Comment struct{ Content string }
 
 var keywordRegexp = regexp.MustCompile(`^(\s*)#\+([^:]+):\s(.*)`)
 var commentRegexp = regexp.MustCompile(`^(\s*)#(.*)`)
+var affiliatedKeywordRegexp = regexp.MustCompile(`^(CAPTION)$`)
 
 func lexKeywordOrComment(line string) (token, bool) {
 	if m := keywordRegexp.FindStringSubmatch(line); m != nil {
@@ -25,12 +31,55 @@ func lexKeywordOrComment(line string) (token, bool) {
 }
 
 func (d *Document) parseKeyword(i int, stop stopFn) (int, Node) {
-	t := d.tokens[i]
-	k, v := t.matches[2], t.matches[3]
-	d.BufferSettings[k] = strings.Join([]string{d.BufferSettings[k], v}, "\n")
-	return 1, Keyword{k, v}
+	k := parseKeyword(d.tokens[i])
+	if affiliatedKeywordRegexp.MatchString(k.Key) {
+		consumed, node := d.parseAffiliated(i, stop)
+		if consumed != 0 {
+			return consumed, node
+		}
+	} else {
+		d.BufferSettings[k.Key] = strings.Join([]string{d.BufferSettings[k.Key], k.Value}, "\n")
+	}
+	return 1, k
 }
 
 func (d *Document) parseComment(i int, stop stopFn) (int, Node) {
 	return 1, Comment{d.tokens[i].content}
 }
+
+func (d *Document) parseAffiliated(i int, stop stopFn) (int, Node) {
+	start, meta := i, map[string]string{}
+	for ; !stop(d, i) && d.tokens[i].kind == "keyword"; i++ {
+		k := parseKeyword(d.tokens[i])
+		if !affiliatedKeywordRegexp.MatchString(k.Key) {
+			return 0, nil
+		}
+		if value, ok := meta[k.Key]; ok {
+			meta[k.Key] = value + " " + k.Value
+		} else {
+			meta[k.Key] = k.Value
+		}
+	}
+	if stop(d, i) {
+		return 0, nil
+	}
+	consumed, node := 0, (Node)(nil)
+	if t := d.tokens[i]; t.kind == "text" {
+		if nodes := d.parseInline(t.content); len(nodes) == 1 && isImageOrVideoLink(nodes[0]) {
+			consumed, node = 1, Line{nodes[:1]}
+		}
+	} else {
+		consumed, node = d.parseOne(i, stop)
+	}
+	if consumed == 0 || node == nil {
+		return 0, nil
+	}
+	i += consumed
+	return i - start, NodeWithMeta{node, meta}
+}
+
+func parseKeyword(t token) Keyword {
+	k, v := t.matches[2], t.matches[3]
+	k = strings.ToUpper(k)
+	return Keyword{k, v}
+}