default namespace = "http://www.iana.org/assignments"

registryMeta =
  attribute id { xsd:ID }
  & element title { text }?
  & element created { genericDate }?
  & element updated { xsd:date }?
  & element registration_rule { text_with_references }?
  & element description { text_with_references }?
  & element note { text_with_references }?
  & references
people =
  element people {
    element person {
      attribute id { xsd:ID },
      element name { text },
      element org { text }?,
      element uri { xsd:anyURI },
      element updated { genericDate }?
    }*
  }
xref =
  element xref {
    attribute lastupdated { genericDate }?,
    ((attribute type { "uri" },
      attribute data { xsd:anyURI })
     | (attribute type { "rfc" },
        attribute data {
          xsd:string { pattern = "(rfc|bcp|std)\d+" }
        })
     | (attribute type { "draft" },
        attribute data {
          xsd:string { pattern = "(draft|RFC)(-[a-zA-Z0-9]+)+" }
        })
     | (attribute type { "registry" },
        attribute data { xsd:NCName })
     | (attribute type { "person" },
        attribute data { xsd:NCName })
     | attribute type { "text" }
     | (attribute type { "note" },
        attribute data { xsd:positiveInteger })),
    text
  }
references = xref*
text_with_references = (text, xref?)*
genericRange =
  xsd:string { pattern = "(\d+|0x[\da-fA-F]+)(-(\d+|0x[\da-fA-F]+))?" }
genericDate = xsd:date | xsd:gYearMonth
footnotes =
  element footnote {
    attribute anchor { xsd:positiveInteger },
    ((text, xref?)*)
  }*