One slight correction: I realised later on that in the current draft spec, unquoted tokens must not start with a digit. Thus the example would be:

    (message
     (previous (hash sha256 |XphMUkWQtomKjXQvFGfsGYpt69sgEY7Y4Vou9cEuJho=|))
     (author (public-key (ed25519 |FCX/tsDLpubCPKKfIrw4gc+SQkHcaD17s7GI6i/ziWY=|)))
     (sequence "216")
     (timestamp "2018-04-19T17:53:26Z")
     (content (type vote)
              (link (hash sha256 |DlBH/hCmXfVzks2uY+WIll4aTzxrfBA8m/3GIdX3Vew=|))
              (value "1")))