namespace a = "http://relaxng.org/ns/compatibility/annotations/1.0"

calendar = element calendar { attlist.calendar, field* }
attlist.calendar &=
  attribute dtstart { text }
attlist.calendar &=
  attribute dtend { text }?
attlist.calendar &=
  attribute mode { "day"
      | "week"
      | "month" }?
attlist.calendar &= [a:defaultValue = "1" ] attribute editable { "0" | "1" }?
attlist.calendar &= attribute color { text }?
attlist.calendar &= attribute background_color { text }?
attlist.calendar &=
  attribute width { text }?
attlist.calendar &=
  attribute height { text }?
field = element field { attlist.field, empty }
attlist.field &= attribute name { text }
data = element data { attlist.data, xpath* }
attlist.data &= empty

xpath = element xpath {
    attlist.xpath, (field | calendar)*
  }
attlist.xpath &= attribute expr { text }
attlist.xpath &=
  [ a:defaultValue = "inside" ]
  attribute position { "inside"
      | "replace"
      | "replace_attributes"
      | "after"
      | "before" }?

start = data | calendar