vendors/tempy.js/parseCommaParts
    function parseCommaParts(str) {
      if (!str)
        return [""];
      var parts = [];
      var m = balanced("{", "}", str);
      if (!m)
        return str.split(",");
      var pre = m.pre;
      var body = m.body;
      var post = m.post;
      var p = pre.split(",");
      p[p.length - 1] += "{" + body + "}";
      var postParts = parseCommaParts(post);
      if (post.length) {
        p[p.length - 1] += postParts.shift();
        p.push.apply(p, postParts);
      }
      parts.push.apply(parts, p);
      return parts;
    }