-- record data:
caption title:
optional string link:

-- data list bar:

-- bar: Data

-- bar: Hello
link: yes

-- foo: $obj.title
$loop$: $bar as $obj
link: $obj.link

-- ftd.row foo:
caption title:
optional string link:

--- ftd.text: $title

--- ftd.text: Not Null
if: $link is not null

--- ftd.text: Null
if: $link is null