namespace xrds = "xri://$xrds"
namespace xrd = "xri://$xrd*($v*2.0)"
namespace local = ""
datatypes xs = "http://www.w3.org/2001/XMLSchema-datatypes"

any.element =
  element * {
    ( attribute* { text }*
     | text
     | any.element )*
  }
  
any.external.element =
  element * - ( xrd:XRD | xrds:XRDS )  {
    ( attribute * { text } *
     | text
     | any.element )*
  }
  
other.attribute = attribute * - ( local:* ) { text }

start = XRDS

XRDS = element xrds:XRDS {
    other.attribute *,
    ( attribute ref { xs:anyURI } | attribute redirect { xs:anyURI } )?,
    ( any.external.element  | XRDS | external "xrd.rnc" )*
}